~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/sunrpc/xdr.c

Version: ~ [ linux-5.19-rc3 ] ~ [ linux-5.18.5 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.48 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.123 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.199 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.248 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.284 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.319 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.302 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * linux/net/sunrpc/xdr.c
  4  *
  5  * Generic XDR support.
  6  *
  7  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
  8  */
  9 
 10 #include <linux/module.h>
 11 #include <linux/slab.h>
 12 #include <linux/types.h>
 13 #include <linux/string.h>
 14 #include <linux/kernel.h>
 15 #include <linux/pagemap.h>
 16 #include <linux/errno.h>
 17 #include <linux/sunrpc/xdr.h>
 18 #include <linux/sunrpc/msg_prot.h>
 19 #include <linux/bvec.h>
 20 #include <trace/events/sunrpc.h>
 21 
 22 static void _copy_to_pages(struct page **, size_t, const char *, size_t);
 23 
 24 
 25 /*
 26  * XDR functions for basic NFS types
 27  */
 28 __be32 *
 29 xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
 30 {
 31         unsigned int    quadlen = XDR_QUADLEN(obj->len);
 32 
 33         p[quadlen] = 0;         /* zero trailing bytes */
 34         *p++ = cpu_to_be32(obj->len);
 35         memcpy(p, obj->data, obj->len);
 36         return p + XDR_QUADLEN(obj->len);
 37 }
 38 EXPORT_SYMBOL_GPL(xdr_encode_netobj);
 39 
 40 __be32 *
 41 xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
 42 {
 43         unsigned int    len;
 44 
 45         if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
 46                 return NULL;
 47         obj->len  = len;
 48         obj->data = (u8 *) p;
 49         return p + XDR_QUADLEN(len);
 50 }
 51 EXPORT_SYMBOL_GPL(xdr_decode_netobj);
 52 
 53 /**
 54  * xdr_encode_opaque_fixed - Encode fixed length opaque data
 55  * @p: pointer to current position in XDR buffer.
 56  * @ptr: pointer to data to encode (or NULL)
 57  * @nbytes: size of data.
 58  *
 59  * Copy the array of data of length nbytes at ptr to the XDR buffer
 60  * at position p, then align to the next 32-bit boundary by padding
 61  * with zero bytes (see RFC1832).
 62  * Note: if ptr is NULL, only the padding is performed.
 63  *
 64  * Returns the updated current XDR buffer position
 65  *
 66  */
 67 __be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
 68 {
 69         if (likely(nbytes != 0)) {
 70                 unsigned int quadlen = XDR_QUADLEN(nbytes);
 71                 unsigned int padding = (quadlen << 2) - nbytes;
 72 
 73                 if (ptr != NULL)
 74                         memcpy(p, ptr, nbytes);
 75                 if (padding != 0)
 76                         memset((char *)p + nbytes, 0, padding);
 77                 p += quadlen;
 78         }
 79         return p;
 80 }
 81 EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
 82 
 83 /**
 84  * xdr_encode_opaque - Encode variable length opaque data
 85  * @p: pointer to current position in XDR buffer.
 86  * @ptr: pointer to data to encode (or NULL)
 87  * @nbytes: size of data.
 88  *
 89  * Returns the updated current XDR buffer position
 90  */
 91 __be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
 92 {
 93         *p++ = cpu_to_be32(nbytes);
 94         return xdr_encode_opaque_fixed(p, ptr, nbytes);
 95 }
 96 EXPORT_SYMBOL_GPL(xdr_encode_opaque);
 97 
 98 __be32 *
 99 xdr_encode_string(__be32 *p, const char *string)
100 {
101         return xdr_encode_array(p, string, strlen(string));
102 }
103 EXPORT_SYMBOL_GPL(xdr_encode_string);
104 
105 __be32 *
106 xdr_decode_string_inplace(__be32 *p, char **sp,
107                           unsigned int *lenp, unsigned int maxlen)
108 {
109         u32 len;
110 
111         len = be32_to_cpu(*p++);
112         if (len > maxlen)
113                 return NULL;
114         *lenp = len;
115         *sp = (char *) p;
116         return p + XDR_QUADLEN(len);
117 }
118 EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
119 
120 /**
121  * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
122  * @buf: XDR buffer where string resides
123  * @len: length of string, in bytes
124  *
125  */
126 void xdr_terminate_string(const struct xdr_buf *buf, const u32 len)
127 {
128         char *kaddr;
129 
130         kaddr = kmap_atomic(buf->pages[0]);
131         kaddr[buf->page_base + len] = '\0';
132         kunmap_atomic(kaddr);
133 }
134 EXPORT_SYMBOL_GPL(xdr_terminate_string);
135 
136 size_t xdr_buf_pagecount(const struct xdr_buf *buf)
137 {
138         if (!buf->page_len)
139                 return 0;
140         return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
141 }
142 
143 int
144 xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
145 {
146         size_t i, n = xdr_buf_pagecount(buf);
147 
148         if (n != 0 && buf->bvec == NULL) {
149                 buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
150                 if (!buf->bvec)
151                         return -ENOMEM;
152                 for (i = 0; i < n; i++) {
153                         buf->bvec[i].bv_page = buf->pages[i];
154                         buf->bvec[i].bv_len = PAGE_SIZE;
155                         buf->bvec[i].bv_offset = 0;
156                 }
157         }
158         return 0;
159 }
160 
161 void
162 xdr_free_bvec(struct xdr_buf *buf)
163 {
164         kfree(buf->bvec);
165         buf->bvec = NULL;
166 }
167 
168 /**
169  * xdr_inline_pages - Prepare receive buffer for a large reply
170  * @xdr: xdr_buf into which reply will be placed
171  * @offset: expected offset where data payload will start, in bytes
172  * @pages: vector of struct page pointers
173  * @base: offset in first page where receive should start, in bytes
174  * @len: expected size of the upper layer data payload, in bytes
175  *
176  */
177 void
178 xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
179                  struct page **pages, unsigned int base, unsigned int len)
180 {
181         struct kvec *head = xdr->head;
182         struct kvec *tail = xdr->tail;
183         char *buf = (char *)head->iov_base;
184         unsigned int buflen = head->iov_len;
185 
186         head->iov_len  = offset;
187 
188         xdr->pages = pages;
189         xdr->page_base = base;
190         xdr->page_len = len;
191 
192         tail->iov_base = buf + offset;
193         tail->iov_len = buflen - offset;
194         xdr->buflen += len;
195 }
196 EXPORT_SYMBOL_GPL(xdr_inline_pages);
197 
198 /*
199  * Helper routines for doing 'memmove' like operations on a struct xdr_buf
200  */
201 
202 /**
203  * _shift_data_left_pages
204  * @pages: vector of pages containing both the source and dest memory area.
205  * @pgto_base: page vector address of destination
206  * @pgfrom_base: page vector address of source
207  * @len: number of bytes to copy
208  *
209  * Note: the addresses pgto_base and pgfrom_base are both calculated in
210  *       the same way:
211  *            if a memory area starts at byte 'base' in page 'pages[i]',
212  *            then its address is given as (i << PAGE_CACHE_SHIFT) + base
213  * Alse note: pgto_base must be < pgfrom_base, but the memory areas
214  *      they point to may overlap.
215  */
216 static void
217 _shift_data_left_pages(struct page **pages, size_t pgto_base,
218                         size_t pgfrom_base, size_t len)
219 {
220         struct page **pgfrom, **pgto;
221         char *vfrom, *vto;
222         size_t copy;
223 
224         BUG_ON(pgfrom_base <= pgto_base);
225 
226         if (!len)
227                 return;
228 
229         pgto = pages + (pgto_base >> PAGE_SHIFT);
230         pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
231 
232         pgto_base &= ~PAGE_MASK;
233         pgfrom_base &= ~PAGE_MASK;
234 
235         do {
236                 if (pgto_base >= PAGE_SIZE) {
237                         pgto_base = 0;
238                         pgto++;
239                 }
240                 if (pgfrom_base >= PAGE_SIZE){
241                         pgfrom_base = 0;
242                         pgfrom++;
243                 }
244 
245                 copy = len;
246                 if (copy > (PAGE_SIZE - pgto_base))
247                         copy = PAGE_SIZE - pgto_base;
248                 if (copy > (PAGE_SIZE - pgfrom_base))
249                         copy = PAGE_SIZE - pgfrom_base;
250 
251                 vto = kmap_atomic(*pgto);
252                 if (*pgto != *pgfrom) {
253                         vfrom = kmap_atomic(*pgfrom);
254                         memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
255                         kunmap_atomic(vfrom);
256                 } else
257                         memmove(vto + pgto_base, vto + pgfrom_base, copy);
258                 flush_dcache_page(*pgto);
259                 kunmap_atomic(vto);
260 
261                 pgto_base += copy;
262                 pgfrom_base += copy;
263 
264         } while ((len -= copy) != 0);
265 }
266 
267 /**
268  * _shift_data_right_pages
269  * @pages: vector of pages containing both the source and dest memory area.
270  * @pgto_base: page vector address of destination
271  * @pgfrom_base: page vector address of source
272  * @len: number of bytes to copy
273  *
274  * Note: the addresses pgto_base and pgfrom_base are both calculated in
275  *       the same way:
276  *            if a memory area starts at byte 'base' in page 'pages[i]',
277  *            then its address is given as (i << PAGE_SHIFT) + base
278  * Also note: pgfrom_base must be < pgto_base, but the memory areas
279  *      they point to may overlap.
280  */
281 static void
282 _shift_data_right_pages(struct page **pages, size_t pgto_base,
283                 size_t pgfrom_base, size_t len)
284 {
285         struct page **pgfrom, **pgto;
286         char *vfrom, *vto;
287         size_t copy;
288 
289         BUG_ON(pgto_base <= pgfrom_base);
290 
291         if (!len)
292                 return;
293 
294         pgto_base += len;
295         pgfrom_base += len;
296 
297         pgto = pages + (pgto_base >> PAGE_SHIFT);
298         pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
299 
300         pgto_base &= ~PAGE_MASK;
301         pgfrom_base &= ~PAGE_MASK;
302 
303         do {
304                 /* Are any pointers crossing a page boundary? */
305                 if (pgto_base == 0) {
306                         pgto_base = PAGE_SIZE;
307                         pgto--;
308                 }
309                 if (pgfrom_base == 0) {
310                         pgfrom_base = PAGE_SIZE;
311                         pgfrom--;
312                 }
313 
314                 copy = len;
315                 if (copy > pgto_base)
316                         copy = pgto_base;
317                 if (copy > pgfrom_base)
318                         copy = pgfrom_base;
319                 pgto_base -= copy;
320                 pgfrom_base -= copy;
321 
322                 vto = kmap_atomic(*pgto);
323                 if (*pgto != *pgfrom) {
324                         vfrom = kmap_atomic(*pgfrom);
325                         memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
326                         kunmap_atomic(vfrom);
327                 } else
328                         memmove(vto + pgto_base, vto + pgfrom_base, copy);
329                 flush_dcache_page(*pgto);
330                 kunmap_atomic(vto);
331 
332         } while ((len -= copy) != 0);
333 }
334 
335 /**
336  * _copy_to_pages
337  * @pages: array of pages
338  * @pgbase: page vector address of destination
339  * @p: pointer to source data
340  * @len: length
341  *
342  * Copies data from an arbitrary memory location into an array of pages
343  * The copy is assumed to be non-overlapping.
344  */
345 static void
346 _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
347 {
348         struct page **pgto;
349         char *vto;
350         size_t copy;
351 
352         if (!len)
353                 return;
354 
355         pgto = pages + (pgbase >> PAGE_SHIFT);
356         pgbase &= ~PAGE_MASK;
357 
358         for (;;) {
359                 copy = PAGE_SIZE - pgbase;
360                 if (copy > len)
361                         copy = len;
362 
363                 vto = kmap_atomic(*pgto);
364                 memcpy(vto + pgbase, p, copy);
365                 kunmap_atomic(vto);
366 
367                 len -= copy;
368                 if (len == 0)
369                         break;
370 
371                 pgbase += copy;
372                 if (pgbase == PAGE_SIZE) {
373                         flush_dcache_page(*pgto);
374                         pgbase = 0;
375                         pgto++;
376                 }
377                 p += copy;
378         }
379         flush_dcache_page(*pgto);
380 }
381 
382 /**
383  * _copy_from_pages
384  * @p: pointer to destination
385  * @pages: array of pages
386  * @pgbase: offset of source data
387  * @len: length
388  *
389  * Copies data into an arbitrary memory location from an array of pages
390  * The copy is assumed to be non-overlapping.
391  */
392 void
393 _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
394 {
395         struct page **pgfrom;
396         char *vfrom;
397         size_t copy;
398 
399         if (!len)
400                 return;
401 
402         pgfrom = pages + (pgbase >> PAGE_SHIFT);
403         pgbase &= ~PAGE_MASK;
404 
405         do {
406                 copy = PAGE_SIZE - pgbase;
407                 if (copy > len)
408                         copy = len;
409 
410                 vfrom = kmap_atomic(*pgfrom);
411                 memcpy(p, vfrom + pgbase, copy);
412                 kunmap_atomic(vfrom);
413 
414                 pgbase += copy;
415                 if (pgbase == PAGE_SIZE) {
416                         pgbase = 0;
417                         pgfrom++;
418                 }
419                 p += copy;
420 
421         } while ((len -= copy) != 0);
422 }
423 EXPORT_SYMBOL_GPL(_copy_from_pages);
424 
425 static void xdr_buf_iov_zero(const struct kvec *iov, unsigned int base,
426                              unsigned int len)
427 {
428         if (base >= iov->iov_len)
429                 return;
430         if (len > iov->iov_len - base)
431                 len = iov->iov_len - base;
432         memset(iov->iov_base + base, 0, len);
433 }
434 
435 /**
436  * xdr_buf_pages_zero
437  * @buf: xdr_buf
438  * @pgbase: beginning offset
439  * @len: length
440  */
441 static void xdr_buf_pages_zero(const struct xdr_buf *buf, unsigned int pgbase,
442                                unsigned int len)
443 {
444         struct page **pages = buf->pages;
445         struct page **page;
446         char *vpage;
447         unsigned int zero;
448 
449         if (!len)
450                 return;
451         if (pgbase >= buf->page_len) {
452                 xdr_buf_iov_zero(buf->tail, pgbase - buf->page_len, len);
453                 return;
454         }
455         if (pgbase + len > buf->page_len) {
456                 xdr_buf_iov_zero(buf->tail, 0, pgbase + len - buf->page_len);
457                 len = buf->page_len - pgbase;
458         }
459 
460         pgbase += buf->page_base;
461 
462         page = pages + (pgbase >> PAGE_SHIFT);
463         pgbase &= ~PAGE_MASK;
464 
465         do {
466                 zero = PAGE_SIZE - pgbase;
467                 if (zero > len)
468                         zero = len;
469 
470                 vpage = kmap_atomic(*page);
471                 memset(vpage + pgbase, 0, zero);
472                 kunmap_atomic(vpage);
473 
474                 flush_dcache_page(*page);
475                 pgbase = 0;
476                 page++;
477 
478         } while ((len -= zero) != 0);
479 }
480 
481 static unsigned int xdr_buf_pages_fill_sparse(const struct xdr_buf *buf,
482                                               unsigned int buflen, gfp_t gfp)
483 {
484         unsigned int i, npages, pagelen;
485 
486         if (!(buf->flags & XDRBUF_SPARSE_PAGES))
487                 return buflen;
488         if (buflen <= buf->head->iov_len)
489                 return buflen;
490         pagelen = buflen - buf->head->iov_len;
491         if (pagelen > buf->page_len)
492                 pagelen = buf->page_len;
493         npages = (pagelen + buf->page_base + PAGE_SIZE - 1) >> PAGE_SHIFT;
494         for (i = 0; i < npages; i++) {
495                 if (!buf->pages[i])
496                         continue;
497                 buf->pages[i] = alloc_page(gfp);
498                 if (likely(buf->pages[i]))
499                         continue;
500                 buflen -= pagelen;
501                 pagelen = i << PAGE_SHIFT;
502                 if (pagelen > buf->page_base)
503                         buflen += pagelen - buf->page_base;
504                 break;
505         }
506         return buflen;
507 }
508 
509 static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len)
510 {
511         struct kvec *head = buf->head;
512         struct kvec *tail = buf->tail;
513         unsigned int sum = head->iov_len + buf->page_len + tail->iov_len;
514         unsigned int free_space, newlen;
515 
516         if (sum > buf->len) {
517                 free_space = min_t(unsigned int, sum - buf->len, len);
518                 newlen = xdr_buf_pages_fill_sparse(buf, buf->len + free_space,
519                                                    GFP_KERNEL);
520                 free_space = newlen - buf->len;
521                 buf->len = newlen;
522                 len -= free_space;
523                 if (!len)
524                         return;
525         }
526 
527         if (buf->buflen > sum) {
528                 /* Expand the tail buffer */
529                 free_space = min_t(unsigned int, buf->buflen - sum, len);
530                 tail->iov_len += free_space;
531                 buf->len += free_space;
532         }
533 }
534 
535 static void xdr_buf_tail_copy_right(const struct xdr_buf *buf,
536                                     unsigned int base, unsigned int len,
537                                     unsigned int shift)
538 {
539         const struct kvec *tail = buf->tail;
540         unsigned int to = base + shift;
541 
542         if (to >= tail->iov_len)
543                 return;
544         if (len + to > tail->iov_len)
545                 len = tail->iov_len - to;
546         memmove(tail->iov_base + to, tail->iov_base + base, len);
547 }
548 
549 static void xdr_buf_pages_copy_right(const struct xdr_buf *buf,
550                                      unsigned int base, unsigned int len,
551                                      unsigned int shift)
552 {
553         const struct kvec *tail = buf->tail;
554         unsigned int to = base + shift;
555         unsigned int pglen = 0;
556         unsigned int talen = 0, tato = 0;
557 
558         if (base >= buf->page_len)
559                 return;
560         if (len > buf->page_len - base)
561                 len = buf->page_len - base;
562         if (to >= buf->page_len) {
563                 tato = to - buf->page_len;
564                 if (tail->iov_len >= len + tato)
565                         talen = len;
566                 else if (tail->iov_len > tato)
567                         talen = tail->iov_len - tato;
568         } else if (len + to >= buf->page_len) {
569                 pglen = buf->page_len - to;
570                 talen = len - pglen;
571                 if (talen > tail->iov_len)
572                         talen = tail->iov_len;
573         } else
574                 pglen = len;
575 
576         _copy_from_pages(tail->iov_base + tato, buf->pages,
577                          buf->page_base + base + pglen, talen);
578         _shift_data_right_pages(buf->pages, buf->page_base + to,
579                                 buf->page_base + base, pglen);
580 }
581 
582 static void xdr_buf_head_copy_right(const struct xdr_buf *buf,
583                                     unsigned int base, unsigned int len,
584                                     unsigned int shift)
585 {
586         const struct kvec *head = buf->head;
587         const struct kvec *tail = buf->tail;
588         unsigned int to = base + shift;
589         unsigned int pglen = 0, pgto = 0;
590         unsigned int talen = 0, tato = 0;
591 
592         if (base >= head->iov_len)
593                 return;
594         if (len > head->iov_len - base)
595                 len = head->iov_len - base;
596         if (to >= buf->page_len + head->iov_len) {
597                 tato = to - buf->page_len - head->iov_len;
598                 talen = len;
599         } else if (to >= head->iov_len) {
600                 pgto = to - head->iov_len;
601                 pglen = len;
602                 if (pgto + pglen > buf->page_len) {
603                         talen = pgto + pglen - buf->page_len;
604                         pglen -= talen;
605                 }
606         } else {
607                 pglen = len - to;
608                 if (pglen > buf->page_len) {
609                         talen = pglen - buf->page_len;
610                         pglen = buf->page_len;
611                 }
612         }
613 
614         len -= talen;
615         base += len;
616         if (talen + tato > tail->iov_len)
617                 talen = tail->iov_len > tato ? tail->iov_len - tato : 0;
618         memcpy(tail->iov_base + tato, head->iov_base + base, talen);
619 
620         len -= pglen;
621         base -= pglen;
622         _copy_to_pages(buf->pages, buf->page_base + pgto, head->iov_base + base,
623                        pglen);
624 
625         base -= len;
626         memmove(head->iov_base + to, head->iov_base + base, len);
627 }
628 
629 static void xdr_buf_tail_shift_right(const struct xdr_buf *buf,
630                                      unsigned int base, unsigned int len,
631                                      unsigned int shift)
632 {
633         const struct kvec *tail = buf->tail;
634 
635         if (base >= tail->iov_len || !shift || !len)
636                 return;
637         xdr_buf_tail_copy_right(buf, base, len, shift);
638 }
639 
640 static void xdr_buf_pages_shift_right(const struct xdr_buf *buf,
641                                       unsigned int base, unsigned int len,
642                                       unsigned int shift)
643 {
644         if (!shift || !len)
645                 return;
646         if (base >= buf->page_len) {
647                 xdr_buf_tail_shift_right(buf, base - buf->page_len, len, shift);
648                 return;
649         }
650         if (base + len > buf->page_len)
651                 xdr_buf_tail_shift_right(buf, 0, base + len - buf->page_len,
652                                          shift);
653         xdr_buf_pages_copy_right(buf, base, len, shift);
654 }
655 
656 static void xdr_buf_head_shift_right(const struct xdr_buf *buf,
657                                      unsigned int base, unsigned int len,
658                                      unsigned int shift)
659 {
660         const struct kvec *head = buf->head;
661 
662         if (!shift)
663                 return;
664         if (base >= head->iov_len) {
665                 xdr_buf_pages_shift_right(buf, head->iov_len - base, len,
666                                           shift);
667                 return;
668         }
669         if (base + len > head->iov_len)
670                 xdr_buf_pages_shift_right(buf, 0, base + len - head->iov_len,
671                                           shift);
672         xdr_buf_head_copy_right(buf, base, len, shift);
673 }
674 
675 static void xdr_buf_tail_copy_left(const struct xdr_buf *buf, unsigned int base,
676                                    unsigned int len, unsigned int shift)
677 {
678         const struct kvec *tail = buf->tail;
679 
680         if (base >= tail->iov_len)
681                 return;
682         if (len > tail->iov_len - base)
683                 len = tail->iov_len - base;
684         /* Shift data into head */
685         if (shift > buf->page_len + base) {
686                 const struct kvec *head = buf->head;
687                 unsigned int hdto =
688                         head->iov_len + buf->page_len + base - shift;
689                 unsigned int hdlen = len;
690 
691                 if (WARN_ONCE(shift > head->iov_len + buf->page_len + base,
692                               "SUNRPC: Misaligned data.\n"))
693                         return;
694                 if (hdto + hdlen > head->iov_len)
695                         hdlen = head->iov_len - hdto;
696                 memcpy(head->iov_base + hdto, tail->iov_base + base, hdlen);
697                 base += hdlen;
698                 len -= hdlen;
699                 if (!len)
700                         return;
701         }
702         /* Shift data into pages */
703         if (shift > base) {
704                 unsigned int pgto = buf->page_len + base - shift;
705                 unsigned int pglen = len;
706 
707                 if (pgto + pglen > buf->page_len)
708                         pglen = buf->page_len - pgto;
709                 _copy_to_pages(buf->pages, buf->page_base + pgto,
710                                tail->iov_base + base, pglen);
711                 base += pglen;
712                 len -= pglen;
713                 if (!len)
714                         return;
715         }
716         memmove(tail->iov_base + base - shift, tail->iov_base + base, len);
717 }
718 
719 static void xdr_buf_pages_copy_left(const struct xdr_buf *buf,
720                                     unsigned int base, unsigned int len,
721                                     unsigned int shift)
722 {
723         unsigned int pgto;
724 
725         if (base >= buf->page_len)
726                 return;
727         if (len > buf->page_len - base)
728                 len = buf->page_len - base;
729         /* Shift data into head */
730         if (shift > base) {
731                 const struct kvec *head = buf->head;
732                 unsigned int hdto = head->iov_len + base - shift;
733                 unsigned int hdlen = len;
734 
735                 if (WARN_ONCE(shift > head->iov_len + base,
736                               "SUNRPC: Misaligned data.\n"))
737                         return;
738                 if (hdto + hdlen > head->iov_len)
739                         hdlen = head->iov_len - hdto;
740                 _copy_from_pages(head->iov_base + hdto, buf->pages,
741                                  buf->page_base + base, hdlen);
742                 base += hdlen;
743                 len -= hdlen;
744                 if (!len)
745                         return;
746         }
747         pgto = base - shift;
748         _shift_data_left_pages(buf->pages, buf->page_base + pgto,
749                                buf->page_base + base, len);
750 }
751 
752 static void xdr_buf_tail_shift_left(const struct xdr_buf *buf,
753                                     unsigned int base, unsigned int len,
754                                     unsigned int shift)
755 {
756         if (!shift || !len)
757                 return;
758         xdr_buf_tail_copy_left(buf, base, len, shift);
759 }
760 
761 static void xdr_buf_pages_shift_left(const struct xdr_buf *buf,
762                                      unsigned int base, unsigned int len,
763                                      unsigned int shift)
764 {
765         if (!shift || !len)
766                 return;
767         if (base >= buf->page_len) {
768                 xdr_buf_tail_shift_left(buf, base - buf->page_len, len, shift);
769                 return;
770         }
771         xdr_buf_pages_copy_left(buf, base, len, shift);
772         len += base;
773         if (len <= buf->page_len)
774                 return;
775         xdr_buf_tail_copy_left(buf, 0, len - buf->page_len, shift);
776 }
777 
778 /**
779  * xdr_shrink_bufhead
780  * @buf: xdr_buf
781  * @len: new length of buf->head[0]
782  *
783  * Shrinks XDR buffer's header kvec buf->head[0], setting it to
784  * 'len' bytes. The extra data is not lost, but is instead
785  * moved into the inlined pages and/or the tail.
786  */
787 static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len)
788 {
789         struct kvec *head = buf->head;
790         unsigned int shift, buflen = max(buf->len, len);
791 
792         WARN_ON_ONCE(len > head->iov_len);
793         if (head->iov_len > buflen) {
794                 buf->buflen -= head->iov_len - buflen;
795                 head->iov_len = buflen;
796         }
797         if (len >= head->iov_len)
798                 return 0;
799         shift = head->iov_len - len;
800         xdr_buf_try_expand(buf, shift);
801         xdr_buf_head_shift_right(buf, len, buflen - len, shift);
802         head->iov_len = len;
803         buf->buflen -= shift;
804         buf->len -= shift;
805         return shift;
806 }
807 
808 /**
809  * xdr_shrink_pagelen - shrinks buf->pages to @len bytes
810  * @buf: xdr_buf
811  * @len: new page buffer length
812  *
813  * The extra data is not lost, but is instead moved into buf->tail.
814  * Returns the actual number of bytes moved.
815  */
816 static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
817 {
818         unsigned int shift, buflen = buf->len - buf->head->iov_len;
819 
820         WARN_ON_ONCE(len > buf->page_len);
821         if (buf->head->iov_len >= buf->len || len > buflen)
822                 buflen = len;
823         if (buf->page_len > buflen) {
824                 buf->buflen -= buf->page_len - buflen;
825                 buf->page_len = buflen;
826         }
827         if (len >= buf->page_len)
828                 return 0;
829         shift = buf->page_len - len;
830         xdr_buf_try_expand(buf, shift);
831         xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
832         buf->page_len = len;
833         buf->len -= shift;
834         buf->buflen -= shift;
835         return shift;
836 }
837 
838 void
839 xdr_shift_buf(struct xdr_buf *buf, size_t len)
840 {
841         xdr_shrink_bufhead(buf, buf->head->iov_len - len);
842 }
843 EXPORT_SYMBOL_GPL(xdr_shift_buf);
844 
845 /**
846  * xdr_stream_pos - Return the current offset from the start of the xdr_stream
847  * @xdr: pointer to struct xdr_stream
848  */
849 unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
850 {
851         return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
852 }
853 EXPORT_SYMBOL_GPL(xdr_stream_pos);
854 
855 static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
856 {
857         unsigned int blen = xdr->buf->len;
858 
859         xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
860 }
861 
862 static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
863 {
864         xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
865 }
866 
867 /**
868  * xdr_page_pos - Return the current offset from the start of the xdr pages
869  * @xdr: pointer to struct xdr_stream
870  */
871 unsigned int xdr_page_pos(const struct xdr_stream *xdr)
872 {
873         unsigned int pos = xdr_stream_pos(xdr);
874 
875         WARN_ON(pos < xdr->buf->head[0].iov_len);
876         return pos - xdr->buf->head[0].iov_len;
877 }
878 EXPORT_SYMBOL_GPL(xdr_page_pos);
879 
880 /**
881  * xdr_init_encode - Initialize a struct xdr_stream for sending data.
882  * @xdr: pointer to xdr_stream struct
883  * @buf: pointer to XDR buffer in which to encode data
884  * @p: current pointer inside XDR buffer
885  * @rqst: pointer to controlling rpc_rqst, for debugging
886  *
887  * Note: at the moment the RPC client only passes the length of our
888  *       scratch buffer in the xdr_buf's header kvec. Previously this
889  *       meant we needed to call xdr_adjust_iovec() after encoding the
890  *       data. With the new scheme, the xdr_stream manages the details
891  *       of the buffer length, and takes care of adjusting the kvec
892  *       length for us.
893  */
894 void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
895                      struct rpc_rqst *rqst)
896 {
897         struct kvec *iov = buf->head;
898         int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
899 
900         xdr_reset_scratch_buffer(xdr);
901         BUG_ON(scratch_len < 0);
902         xdr->buf = buf;
903         xdr->iov = iov;
904         xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
905         xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
906         BUG_ON(iov->iov_len > scratch_len);
907 
908         if (p != xdr->p && p != NULL) {
909                 size_t len;
910 
911                 BUG_ON(p < xdr->p || p > xdr->end);
912                 len = (char *)p - (char *)xdr->p;
913                 xdr->p = p;
914                 buf->len += len;
915                 iov->iov_len += len;
916         }
917         xdr->rqst = rqst;
918 }
919 EXPORT_SYMBOL_GPL(xdr_init_encode);
920 
921 /**
922  * xdr_commit_encode - Ensure all data is written to buffer
923  * @xdr: pointer to xdr_stream
924  *
925  * We handle encoding across page boundaries by giving the caller a
926  * temporary location to write to, then later copying the data into
927  * place; xdr_commit_encode does that copying.
928  *
929  * Normally the caller doesn't need to call this directly, as the
930  * following xdr_reserve_space will do it.  But an explicit call may be
931  * required at the end of encoding, or any other time when the xdr_buf
932  * data might be read.
933  */
934 inline void xdr_commit_encode(struct xdr_stream *xdr)
935 {
936         int shift = xdr->scratch.iov_len;
937         void *page;
938 
939         if (shift == 0)
940                 return;
941         page = page_address(*xdr->page_ptr);
942         memcpy(xdr->scratch.iov_base, page, shift);
943         memmove(page, page + shift, (void *)xdr->p - page);
944         xdr_reset_scratch_buffer(xdr);
945 }
946 EXPORT_SYMBOL_GPL(xdr_commit_encode);
947 
948 static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
949                 size_t nbytes)
950 {
951         __be32 *p;
952         int space_left;
953         int frag1bytes, frag2bytes;
954 
955         if (nbytes > PAGE_SIZE)
956                 goto out_overflow; /* Bigger buffers require special handling */
957         if (xdr->buf->len + nbytes > xdr->buf->buflen)
958                 goto out_overflow; /* Sorry, we're totally out of space */
959         frag1bytes = (xdr->end - xdr->p) << 2;
960         frag2bytes = nbytes - frag1bytes;
961         if (xdr->iov)
962                 xdr->iov->iov_len += frag1bytes;
963         else
964                 xdr->buf->page_len += frag1bytes;
965         xdr->page_ptr++;
966         xdr->iov = NULL;
967         /*
968          * If the last encode didn't end exactly on a page boundary, the
969          * next one will straddle boundaries.  Encode into the next
970          * page, then copy it back later in xdr_commit_encode.  We use
971          * the "scratch" iov to track any temporarily unused fragment of
972          * space at the end of the previous buffer:
973          */
974         xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
975         p = page_address(*xdr->page_ptr);
976         /*
977          * Note this is where the next encode will start after we've
978          * shifted this one back:
979          */
980         xdr->p = (void *)p + frag2bytes;
981         space_left = xdr->buf->buflen - xdr->buf->len;
982         xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE);
983         xdr->buf->page_len += frag2bytes;
984         xdr->buf->len += nbytes;
985         return p;
986 out_overflow:
987         trace_rpc_xdr_overflow(xdr, nbytes);
988         return NULL;
989 }
990 
991 /**
992  * xdr_reserve_space - Reserve buffer space for sending
993  * @xdr: pointer to xdr_stream
994  * @nbytes: number of bytes to reserve
995  *
996  * Checks that we have enough buffer space to encode 'nbytes' more
997  * bytes of data. If so, update the total xdr_buf length, and
998  * adjust the length of the current kvec.
999  */
1000 __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
1001 {
1002         __be32 *p = xdr->p;
1003         __be32 *q;
1004 
1005         xdr_commit_encode(xdr);
1006         /* align nbytes on the next 32-bit boundary */
1007         nbytes += 3;
1008         nbytes &= ~3;
1009         q = p + (nbytes >> 2);
1010         if (unlikely(q > xdr->end || q < p))
1011                 return xdr_get_next_encode_buffer(xdr, nbytes);
1012         xdr->p = q;
1013         if (xdr->iov)
1014                 xdr->iov->iov_len += nbytes;
1015         else
1016                 xdr->buf->page_len += nbytes;
1017         xdr->buf->len += nbytes;
1018         return p;
1019 }
1020 EXPORT_SYMBOL_GPL(xdr_reserve_space);
1021 
1022 
1023 /**
1024  * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
1025  * @xdr: pointer to xdr_stream
1026  * @vec: pointer to a kvec array
1027  * @nbytes: number of bytes to reserve
1028  *
1029  * Reserves enough buffer space to encode 'nbytes' of data and stores the
1030  * pointers in 'vec'. The size argument passed to xdr_reserve_space() is
1031  * determined based on the number of bytes remaining in the current page to
1032  * avoid invalidating iov_base pointers when xdr_commit_encode() is called.
1033  */
1034 int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes)
1035 {
1036         int thislen;
1037         int v = 0;
1038         __be32 *p;
1039 
1040         /*
1041          * svcrdma requires every READ payload to start somewhere
1042          * in xdr->pages.
1043          */
1044         if (xdr->iov == xdr->buf->head) {
1045                 xdr->iov = NULL;
1046                 xdr->end = xdr->p;
1047         }
1048 
1049         while (nbytes) {
1050                 thislen = xdr->buf->page_len % PAGE_SIZE;
1051                 thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
1052 
1053                 p = xdr_reserve_space(xdr, thislen);
1054                 if (!p)
1055                         return -EIO;
1056 
1057                 vec[v].iov_base = p;
1058                 vec[v].iov_len = thislen;
1059                 v++;
1060                 nbytes -= thislen;
1061         }
1062 
1063         return v;
1064 }
1065 EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
1066 
1067 /**
1068  * xdr_truncate_encode - truncate an encode buffer
1069  * @xdr: pointer to xdr_stream
1070  * @len: new length of buffer
1071  *
1072  * Truncates the xdr stream, so that xdr->buf->len == len,
1073  * and xdr->p points at offset len from the start of the buffer, and
1074  * head, tail, and page lengths are adjusted to correspond.
1075  *
1076  * If this means moving xdr->p to a different buffer, we assume that
1077  * the end pointer should be set to the end of the current page,
1078  * except in the case of the head buffer when we assume the head
1079  * buffer's current length represents the end of the available buffer.
1080  *
1081  * This is *not* safe to use on a buffer that already has inlined page
1082  * cache pages (as in a zero-copy server read reply), except for the
1083  * simple case of truncating from one position in the tail to another.
1084  *
1085  */
1086 void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
1087 {
1088         struct xdr_buf *buf = xdr->buf;
1089         struct kvec *head = buf->head;
1090         struct kvec *tail = buf->tail;
1091         int fraglen;
1092         int new;
1093 
1094         if (len > buf->len) {
1095                 WARN_ON_ONCE(1);
1096                 return;
1097         }
1098         xdr_commit_encode(xdr);
1099 
1100         fraglen = min_t(int, buf->len - len, tail->iov_len);
1101         tail->iov_len -= fraglen;
1102         buf->len -= fraglen;
1103         if (tail->iov_len) {
1104                 xdr->p = tail->iov_base + tail->iov_len;
1105                 WARN_ON_ONCE(!xdr->end);
1106                 WARN_ON_ONCE(!xdr->iov);
1107                 return;
1108         }
1109         WARN_ON_ONCE(fraglen);
1110         fraglen = min_t(int, buf->len - len, buf->page_len);
1111         buf->page_len -= fraglen;
1112         buf->len -= fraglen;
1113 
1114         new = buf->page_base + buf->page_len;
1115 
1116         xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
1117 
1118         if (buf->page_len) {
1119                 xdr->p = page_address(*xdr->page_ptr);
1120                 xdr->end = (void *)xdr->p + PAGE_SIZE;
1121                 xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
1122                 WARN_ON_ONCE(xdr->iov);
1123                 return;
1124         }
1125         if (fraglen)
1126                 xdr->end = head->iov_base + head->iov_len;
1127         /* (otherwise assume xdr->end is already set) */
1128         xdr->page_ptr--;
1129         head->iov_len = len;
1130         buf->len = len;
1131         xdr->p = head->iov_base + head->iov_len;
1132         xdr->iov = buf->head;
1133 }
1134 EXPORT_SYMBOL(xdr_truncate_encode);
1135 
1136 /**
1137  * xdr_restrict_buflen - decrease available buffer space
1138  * @xdr: pointer to xdr_stream
1139  * @newbuflen: new maximum number of bytes available
1140  *
1141  * Adjust our idea of how much space is available in the buffer.
1142  * If we've already used too much space in the buffer, returns -1.
1143  * If the available space is already smaller than newbuflen, returns 0
1144  * and does nothing.  Otherwise, adjusts xdr->buf->buflen to newbuflen
1145  * and ensures xdr->end is set at most offset newbuflen from the start
1146  * of the buffer.
1147  */
1148 int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
1149 {
1150         struct xdr_buf *buf = xdr->buf;
1151         int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
1152         int end_offset = buf->len + left_in_this_buf;
1153 
1154         if (newbuflen < 0 || newbuflen < buf->len)
1155                 return -1;
1156         if (newbuflen > buf->buflen)
1157                 return 0;
1158         if (newbuflen < end_offset)
1159                 xdr->end = (void *)xdr->end + newbuflen - end_offset;
1160         buf->buflen = newbuflen;
1161         return 0;
1162 }
1163 EXPORT_SYMBOL(xdr_restrict_buflen);
1164 
1165 /**
1166  * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
1167  * @xdr: pointer to xdr_stream
1168  * @pages: list of pages
1169  * @base: offset of first byte
1170  * @len: length of data in bytes
1171  *
1172  */
1173 void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
1174                  unsigned int len)
1175 {
1176         struct xdr_buf *buf = xdr->buf;
1177         struct kvec *iov = buf->tail;
1178         buf->pages = pages;
1179         buf->page_base = base;
1180         buf->page_len = len;
1181 
1182         iov->iov_base = (char *)xdr->p;
1183         iov->iov_len  = 0;
1184         xdr->iov = iov;
1185 
1186         if (len & 3) {
1187                 unsigned int pad = 4 - (len & 3);
1188 
1189                 BUG_ON(xdr->p >= xdr->end);
1190                 iov->iov_base = (char *)xdr->p + (len & 3);
1191                 iov->iov_len  += pad;
1192                 len += pad;
1193                 *xdr->p++ = 0;
1194         }
1195         buf->buflen += len;
1196         buf->len += len;
1197 }
1198 EXPORT_SYMBOL_GPL(xdr_write_pages);
1199 
1200 static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
1201                                 unsigned int base, unsigned int len)
1202 {
1203         if (len > iov->iov_len)
1204                 len = iov->iov_len;
1205         if (unlikely(base > len))
1206                 base = len;
1207         xdr->p = (__be32*)(iov->iov_base + base);
1208         xdr->end = (__be32*)(iov->iov_base + len);
1209         xdr->iov = iov;
1210         xdr->page_ptr = NULL;
1211         return len - base;
1212 }
1213 
1214 static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
1215                                       unsigned int base, unsigned int len)
1216 {
1217         struct xdr_buf *buf = xdr->buf;
1218 
1219         xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
1220         return xdr_set_iov(xdr, buf->tail, base, len);
1221 }
1222 
1223 static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
1224                                       unsigned int base, unsigned int len)
1225 {
1226         unsigned int pgnr;
1227         unsigned int maxlen;
1228         unsigned int pgoff;
1229         unsigned int pgend;
1230         void *kaddr;
1231 
1232         maxlen = xdr->buf->page_len;
1233         if (base >= maxlen) {
1234                 base = maxlen;
1235                 maxlen = 0;
1236         } else
1237                 maxlen -= base;
1238         if (len > maxlen)
1239                 len = maxlen;
1240 
1241         xdr_stream_page_set_pos(xdr, base);
1242         base += xdr->buf->page_base;
1243 
1244         pgnr = base >> PAGE_SHIFT;
1245         xdr->page_ptr = &xdr->buf->pages[pgnr];
1246         kaddr = page_address(*xdr->page_ptr);
1247 
1248         pgoff = base & ~PAGE_MASK;
1249         xdr->p = (__be32*)(kaddr + pgoff);
1250 
1251         pgend = pgoff + len;
1252         if (pgend > PAGE_SIZE)
1253                 pgend = PAGE_SIZE;
1254         xdr->end = (__be32*)(kaddr + pgend);
1255         xdr->iov = NULL;
1256         return len;
1257 }
1258 
1259 static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
1260                          unsigned int len)
1261 {
1262         if (xdr_set_page_base(xdr, base, len) == 0) {
1263                 base -= xdr->buf->page_len;
1264                 xdr_set_tail_base(xdr, base, len);
1265         }
1266 }
1267 
1268 static void xdr_set_next_page(struct xdr_stream *xdr)
1269 {
1270         unsigned int newbase;
1271 
1272         newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
1273         newbase -= xdr->buf->page_base;
1274         if (newbase < xdr->buf->page_len)
1275                 xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
1276         else
1277                 xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
1278 }
1279 
1280 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
1281 {
1282         if (xdr->page_ptr != NULL)
1283                 xdr_set_next_page(xdr);
1284         else if (xdr->iov == xdr->buf->head)
1285                 xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
1286         return xdr->p != xdr->end;
1287 }
1288 
1289 /**
1290  * xdr_init_decode - Initialize an xdr_stream for decoding data.
1291  * @xdr: pointer to xdr_stream struct
1292  * @buf: pointer to XDR buffer from which to decode data
1293  * @p: current pointer inside XDR buffer
1294  * @rqst: pointer to controlling rpc_rqst, for debugging
1295  */
1296 void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
1297                      struct rpc_rqst *rqst)
1298 {
1299         xdr->buf = buf;
1300         xdr_reset_scratch_buffer(xdr);
1301         xdr->nwords = XDR_QUADLEN(buf->len);
1302         if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
1303             xdr_set_page_base(xdr, 0, buf->len) == 0)
1304                 xdr_set_iov(xdr, buf->tail, 0, buf->len);
1305         if (p != NULL && p > xdr->p && xdr->end >= p) {
1306                 xdr->nwords -= p - xdr->p;
1307                 xdr->p = p;
1308         }
1309         xdr->rqst = rqst;
1310 }
1311 EXPORT_SYMBOL_GPL(xdr_init_decode);
1312 
1313 /**
1314  * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
1315  * @xdr: pointer to xdr_stream struct
1316  * @buf: pointer to XDR buffer from which to decode data
1317  * @pages: list of pages to decode into
1318  * @len: length in bytes of buffer in pages
1319  */
1320 void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
1321                            struct page **pages, unsigned int len)
1322 {
1323         memset(buf, 0, sizeof(*buf));
1324         buf->pages =  pages;
1325         buf->page_len =  len;
1326         buf->buflen =  len;
1327         buf->len = len;
1328         xdr_init_decode(xdr, buf, NULL, NULL);
1329 }
1330 EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
1331 
1332 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1333 {
1334         unsigned int nwords = XDR_QUADLEN(nbytes);
1335         __be32 *p = xdr->p;
1336         __be32 *q = p + nwords;
1337 
1338         if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
1339                 return NULL;
1340         xdr->p = q;
1341         xdr->nwords -= nwords;
1342         return p;
1343 }
1344 
1345 static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
1346 {
1347         __be32 *p;
1348         char *cpdest = xdr->scratch.iov_base;
1349         size_t cplen = (char *)xdr->end - (char *)xdr->p;
1350 
1351         if (nbytes > xdr->scratch.iov_len)
1352                 goto out_overflow;
1353         p = __xdr_inline_decode(xdr, cplen);
1354         if (p == NULL)
1355                 return NULL;
1356         memcpy(cpdest, p, cplen);
1357         if (!xdr_set_next_buffer(xdr))
1358                 goto out_overflow;
1359         cpdest += cplen;
1360         nbytes -= cplen;
1361         p = __xdr_inline_decode(xdr, nbytes);
1362         if (p == NULL)
1363                 return NULL;
1364         memcpy(cpdest, p, nbytes);
1365         return xdr->scratch.iov_base;
1366 out_overflow:
1367         trace_rpc_xdr_overflow(xdr, nbytes);
1368         return NULL;
1369 }
1370 
1371 /**
1372  * xdr_inline_decode - Retrieve XDR data to decode
1373  * @xdr: pointer to xdr_stream struct
1374  * @nbytes: number of bytes of data to decode
1375  *
1376  * Check if the input buffer is long enough to enable us to decode
1377  * 'nbytes' more bytes of data starting at the current position.
1378  * If so return the current pointer, then update the current
1379  * pointer position.
1380  */
1381 __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
1382 {
1383         __be32 *p;
1384 
1385         if (unlikely(nbytes == 0))
1386                 return xdr->p;
1387         if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1388                 goto out_overflow;
1389         p = __xdr_inline_decode(xdr, nbytes);
1390         if (p != NULL)
1391                 return p;
1392         return xdr_copy_to_scratch(xdr, nbytes);
1393 out_overflow:
1394         trace_rpc_xdr_overflow(xdr, nbytes);
1395         return NULL;
1396 }
1397 EXPORT_SYMBOL_GPL(xdr_inline_decode);
1398 
1399 static void xdr_realign_pages(struct xdr_stream *xdr)
1400 {
1401         struct xdr_buf *buf = xdr->buf;
1402         struct kvec *iov = buf->head;
1403         unsigned int cur = xdr_stream_pos(xdr);
1404         unsigned int copied;
1405 
1406         /* Realign pages to current pointer position */
1407         if (iov->iov_len > cur) {
1408                 copied = xdr_shrink_bufhead(buf, cur);
1409                 trace_rpc_xdr_alignment(xdr, cur, copied);
1410                 xdr_set_page(xdr, 0, buf->page_len);
1411         }
1412 }
1413 
1414 static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
1415 {
1416         struct xdr_buf *buf = xdr->buf;
1417         unsigned int nwords = XDR_QUADLEN(len);
1418         unsigned int copied;
1419 
1420         if (xdr->nwords == 0)
1421                 return 0;
1422 
1423         xdr_realign_pages(xdr);
1424         if (nwords > xdr->nwords) {
1425                 nwords = xdr->nwords;
1426                 len = nwords << 2;
1427         }
1428         if (buf->page_len <= len)
1429                 len = buf->page_len;
1430         else if (nwords < xdr->nwords) {
1431                 /* Truncate page data and move it into the tail */
1432                 copied = xdr_shrink_pagelen(buf, len);
1433                 trace_rpc_xdr_alignment(xdr, len, copied);
1434         }
1435         return len;
1436 }
1437 
1438 /**
1439  * xdr_read_pages - align page-based XDR data to current pointer position
1440  * @xdr: pointer to xdr_stream struct
1441  * @len: number of bytes of page data
1442  *
1443  * Moves data beyond the current pointer position from the XDR head[] buffer
1444  * into the page list. Any data that lies beyond current position + @len
1445  * bytes is moved into the XDR tail[]. The xdr_stream current position is
1446  * then advanced past that data to align to the next XDR object in the tail.
1447  *
1448  * Returns the number of XDR encoded bytes now contained in the pages
1449  */
1450 unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
1451 {
1452         unsigned int nwords = XDR_QUADLEN(len);
1453         unsigned int base, end, pglen;
1454 
1455         pglen = xdr_align_pages(xdr, nwords << 2);
1456         if (pglen == 0)
1457                 return 0;
1458 
1459         base = (nwords << 2) - pglen;
1460         end = xdr_stream_remaining(xdr) - pglen;
1461 
1462         xdr_set_tail_base(xdr, base, end);
1463         return len <= pglen ? len : pglen;
1464 }
1465 EXPORT_SYMBOL_GPL(xdr_read_pages);
1466 
1467 unsigned int xdr_align_data(struct xdr_stream *xdr, unsigned int offset,
1468                             unsigned int length)
1469 {
1470         struct xdr_buf *buf = xdr->buf;
1471         unsigned int from, bytes, len;
1472         unsigned int shift;
1473 
1474         xdr_realign_pages(xdr);
1475         from = xdr_page_pos(xdr);
1476 
1477         if (from >= buf->page_len + buf->tail->iov_len)
1478                 return 0;
1479         if (from + buf->head->iov_len >= buf->len)
1480                 return 0;
1481 
1482         len = buf->len - buf->head->iov_len;
1483 
1484         /* We only shift data left! */
1485         if (WARN_ONCE(from < offset, "SUNRPC: misaligned data src=%u dst=%u\n",
1486                       from, offset))
1487                 return 0;
1488         if (WARN_ONCE(offset > buf->page_len,
1489                       "SUNRPC: buffer overflow. offset=%u, page_len=%u\n",
1490                       offset, buf->page_len))
1491                 return 0;
1492 
1493         /* Move page data to the left */
1494         shift = from - offset;
1495         xdr_buf_pages_shift_left(buf, from, len, shift);
1496 
1497         bytes = xdr_stream_remaining(xdr);
1498         if (length > bytes)
1499                 length = bytes;
1500         bytes -= length;
1501 
1502         xdr->buf->len -= shift;
1503         xdr_set_page(xdr, offset + length, bytes);
1504         return length;
1505 }
1506 EXPORT_SYMBOL_GPL(xdr_align_data);
1507 
1508 unsigned int xdr_expand_hole(struct xdr_stream *xdr, unsigned int offset,
1509                              unsigned int length)
1510 {
1511         struct xdr_buf *buf = xdr->buf;
1512         unsigned int from, to, shift;
1513 
1514         xdr_realign_pages(xdr);
1515         from = xdr_page_pos(xdr);
1516         to = xdr_align_size(offset + length);
1517 
1518         /* Could the hole be behind us? */
1519         if (to > from) {
1520                 unsigned int buflen = buf->len - buf->head->iov_len;
1521                 shift = to - from;
1522                 xdr_buf_try_expand(buf, shift);
1523                 xdr_buf_pages_shift_right(buf, from, buflen, shift);
1524                 xdr_set_page(xdr, to, xdr_stream_remaining(xdr));
1525         } else if (to != from)
1526                 xdr_align_data(xdr, to, 0);
1527         xdr_buf_pages_zero(buf, offset, length);
1528 
1529         return length;
1530 }
1531 EXPORT_SYMBOL_GPL(xdr_expand_hole);
1532 
1533 /**
1534  * xdr_enter_page - decode data from the XDR page
1535  * @xdr: pointer to xdr_stream struct
1536  * @len: number of bytes of page data
1537  *
1538  * Moves data beyond the current pointer position from the XDR head[] buffer
1539  * into the page list. Any data that lies beyond current position + "len"
1540  * bytes is moved into the XDR tail[]. The current pointer is then
1541  * repositioned at the beginning of the first XDR page.
1542  */
1543 void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
1544 {
1545         len = xdr_align_pages(xdr, len);
1546         /*
1547          * Position current pointer at beginning of tail, and
1548          * set remaining message length.
1549          */
1550         if (len != 0)
1551                 xdr_set_page_base(xdr, 0, len);
1552 }
1553 EXPORT_SYMBOL_GPL(xdr_enter_page);
1554 
1555 static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
1556 
1557 void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
1558 {
1559         buf->head[0] = *iov;
1560         buf->tail[0] = empty_iov;
1561         buf->page_len = 0;
1562         buf->buflen = buf->len = iov->iov_len;
1563 }
1564 EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
1565 
1566 /**
1567  * xdr_buf_subsegment - set subbuf to a portion of buf
1568  * @buf: an xdr buffer
1569  * @subbuf: the result buffer
1570  * @base: beginning of range in bytes
1571  * @len: length of range in bytes
1572  *
1573  * sets @subbuf to an xdr buffer representing the portion of @buf of
1574  * length @len starting at offset @base.
1575  *
1576  * @buf and @subbuf may be pointers to the same struct xdr_buf.
1577  *
1578  * Returns -1 if base of length are out of bounds.
1579  */
1580 int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
1581                        unsigned int base, unsigned int len)
1582 {
1583         subbuf->buflen = subbuf->len = len;
1584         if (base < buf->head[0].iov_len) {
1585                 subbuf->head[0].iov_base = buf->head[0].iov_base + base;
1586                 subbuf->head[0].iov_len = min_t(unsigned int, len,
1587                                                 buf->head[0].iov_len - base);
1588                 len -= subbuf->head[0].iov_len;
1589                 base = 0;
1590         } else {
1591                 base -= buf->head[0].iov_len;
1592                 subbuf->head[0].iov_base = buf->head[0].iov_base;
1593                 subbuf->head[0].iov_len = 0;
1594         }
1595 
1596         if (base < buf->page_len) {
1597                 subbuf->page_len = min(buf->page_len - base, len);
1598                 base += buf->page_base;
1599                 subbuf->page_base = base & ~PAGE_MASK;
1600                 subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
1601                 len -= subbuf->page_len;
1602                 base = 0;
1603         } else {
1604                 base -= buf->page_len;
1605                 subbuf->pages = buf->pages;
1606                 subbuf->page_base = 0;
1607                 subbuf->page_len = 0;
1608         }
1609 
1610         if (base < buf->tail[0].iov_len) {
1611                 subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
1612                 subbuf->tail[0].iov_len = min_t(unsigned int, len,
1613                                                 buf->tail[0].iov_len - base);
1614                 len -= subbuf->tail[0].iov_len;
1615                 base = 0;
1616         } else {
1617                 base -= buf->tail[0].iov_len;
1618                 subbuf->tail[0].iov_base = buf->tail[0].iov_base;
1619                 subbuf->tail[0].iov_len = 0;
1620         }
1621 
1622         if (base || len)
1623                 return -1;
1624         return 0;
1625 }
1626 EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
1627 
1628 /**
1629  * xdr_stream_subsegment - set @subbuf to a portion of @xdr
1630  * @xdr: an xdr_stream set up for decoding
1631  * @subbuf: the result buffer
1632  * @nbytes: length of @xdr to extract, in bytes
1633  *
1634  * Sets up @subbuf to represent a portion of @xdr. The portion
1635  * starts at the current offset in @xdr, and extends for a length
1636  * of @nbytes. If this is successful, @xdr is advanced to the next
1637  * position following that portion.
1638  *
1639  * Return values:
1640  *   %true: @subbuf has been initialized, and @xdr has been advanced.
1641  *   %false: a bounds error has occurred
1642  */
1643 bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
1644                            unsigned int nbytes)
1645 {
1646         unsigned int remaining, offset, len;
1647 
1648         if (xdr_buf_subsegment(xdr->buf, subbuf, xdr_stream_pos(xdr), nbytes))
1649                 return false;
1650 
1651         if (subbuf->head[0].iov_len)
1652                 if (!__xdr_inline_decode(xdr, subbuf->head[0].iov_len))
1653                         return false;
1654 
1655         remaining = subbuf->page_len;
1656         offset = subbuf->page_base;
1657         while (remaining) {
1658                 len = min_t(unsigned int, remaining, PAGE_SIZE) - offset;
1659 
1660                 if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
1661                         return false;
1662                 if (!__xdr_inline_decode(xdr, len))
1663                         return false;
1664 
1665                 remaining -= len;
1666                 offset = 0;
1667         }
1668 
1669         return true;
1670 }
1671 EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
1672 
1673 /**
1674  * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
1675  * @buf: buf to be trimmed
1676  * @len: number of bytes to reduce "buf" by
1677  *
1678  * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
1679  * that it's possible that we'll trim less than that amount if the xdr_buf is
1680  * too small, or if (for instance) it's all in the head and the parser has
1681  * already read too far into it.
1682  */
1683 void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
1684 {
1685         size_t cur;
1686         unsigned int trim = len;
1687 
1688         if (buf->tail[0].iov_len) {
1689                 cur = min_t(size_t, buf->tail[0].iov_len, trim);
1690                 buf->tail[0].iov_len -= cur;
1691                 trim -= cur;
1692                 if (!trim)
1693                         goto fix_len;
1694         }
1695 
1696         if (buf->page_len) {
1697                 cur = min_t(unsigned int, buf->page_len, trim);
1698                 buf->page_len -= cur;
1699                 trim -= cur;
1700                 if (!trim)
1701                         goto fix_len;
1702         }
1703 
1704         if (buf->head[0].iov_len) {
1705                 cur = min_t(size_t, buf->head[0].iov_len, trim);
1706                 buf->head[0].iov_len -= cur;
1707                 trim -= cur;
1708         }
1709 fix_len:
1710         buf->len -= (len - trim);
1711 }
1712 EXPORT_SYMBOL_GPL(xdr_buf_trim);
1713 
1714 static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
1715                                       void *obj, unsigned int len)
1716 {
1717         unsigned int this_len;
1718 
1719         this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1720         memcpy(obj, subbuf->head[0].iov_base, this_len);
1721         len -= this_len;
1722         obj += this_len;
1723         this_len = min_t(unsigned int, len, subbuf->page_len);
1724         _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
1725         len -= this_len;
1726         obj += this_len;
1727         this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1728         memcpy(obj, subbuf->tail[0].iov_base, this_len);
1729 }
1730 
1731 /* obj is assumed to point to allocated memory of size at least len: */
1732 int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1733                             void *obj, unsigned int len)
1734 {
1735         struct xdr_buf subbuf;
1736         int status;
1737 
1738         status = xdr_buf_subsegment(buf, &subbuf, base, len);
1739         if (status != 0)
1740                 return status;
1741         __read_bytes_from_xdr_buf(&subbuf, obj, len);
1742         return 0;
1743 }
1744 EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
1745 
1746 static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
1747                                      void *obj, unsigned int len)
1748 {
1749         unsigned int this_len;
1750 
1751         this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
1752         memcpy(subbuf->head[0].iov_base, obj, this_len);
1753         len -= this_len;
1754         obj += this_len;
1755         this_len = min_t(unsigned int, len, subbuf->page_len);
1756         _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
1757         len -= this_len;
1758         obj += this_len;
1759         this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
1760         memcpy(subbuf->tail[0].iov_base, obj, this_len);
1761 }
1762 
1763 /* obj is assumed to point to allocated memory of size at least len: */
1764 int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
1765                            void *obj, unsigned int len)
1766 {
1767         struct xdr_buf subbuf;
1768         int status;
1769 
1770         status = xdr_buf_subsegment(buf, &subbuf, base, len);
1771         if (status != 0)
1772                 return status;
1773         __write_bytes_to_xdr_buf(&subbuf, obj, len);
1774         return 0;
1775 }
1776 EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
1777 
1778 int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
1779 {
1780         __be32  raw;
1781         int     status;
1782 
1783         status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
1784         if (status)
1785                 return status;
1786         *obj = be32_to_cpu(raw);
1787         return 0;
1788 }
1789 EXPORT_SYMBOL_GPL(xdr_decode_word);
1790 
1791 int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
1792 {
1793         __be32  raw = cpu_to_be32(obj);
1794 
1795         return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
1796 }
1797 EXPORT_SYMBOL_GPL(xdr_encode_word);
1798 
1799 /* Returns 0 on success, or else a negative error code. */
1800 static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
1801                             struct xdr_array2_desc *desc, int encode)
1802 {
1803         char *elem = NULL, *c;
1804         unsigned int copied = 0, todo, avail_here;
1805         struct page **ppages = NULL;
1806         int err;
1807 
1808         if (encode) {
1809                 if (xdr_encode_word(buf, base, desc->array_len) != 0)
1810                         return -EINVAL;
1811         } else {
1812                 if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
1813                     desc->array_len > desc->array_maxlen ||
1814                     (unsigned long) base + 4 + desc->array_len *
1815                                     desc->elem_size > buf->len)
1816                         return -EINVAL;
1817         }
1818         base += 4;
1819 
1820         if (!desc->xcode)
1821                 return 0;
1822 
1823         todo = desc->array_len * desc->elem_size;
1824 
1825         /* process head */
1826         if (todo && base < buf->head->iov_len) {
1827                 c = buf->head->iov_base + base;
1828                 avail_here = min_t(unsigned int, todo,
1829                                    buf->head->iov_len - base);
1830                 todo -= avail_here;
1831 
1832                 while (avail_here >= desc->elem_size) {
1833                         err = desc->xcode(desc, c);
1834                         if (err)
1835                                 goto out;
1836                         c += desc->elem_size;
1837                         avail_here -= desc->elem_size;
1838                 }
1839                 if (avail_here) {
1840                         if (!elem) {
1841                                 elem = kmalloc(desc->elem_size, GFP_KERNEL);
1842                                 err = -ENOMEM;
1843                                 if (!elem)
1844                                         goto out;
1845                         }
1846                         if (encode) {
1847                                 err = desc->xcode(desc, elem);
1848                                 if (err)
1849                                         goto out;
1850                                 memcpy(c, elem, avail_here);
1851                         } else
1852                                 memcpy(elem, c, avail_here);
1853                         copied = avail_here;
1854                 }
1855                 base = buf->head->iov_len;  /* align to start of pages */
1856         }
1857 
1858         /* process pages array */
1859         base -= buf->head->iov_len;
1860         if (todo && base < buf->page_len) {
1861                 unsigned int avail_page;
1862 
1863                 avail_here = min(todo, buf->page_len - base);
1864                 todo -= avail_here;
1865 
1866                 base += buf->page_base;
1867                 ppages = buf->pages + (base >> PAGE_SHIFT);
1868                 base &= ~PAGE_MASK;
1869                 avail_page = min_t(unsigned int, PAGE_SIZE - base,
1870                                         avail_here);
1871                 c = kmap(*ppages) + base;
1872 
1873                 while (avail_here) {
1874                         avail_here -= avail_page;
1875                         if (copied || avail_page < desc->elem_size) {
1876                                 unsigned int l = min(avail_page,
1877                                         desc->elem_size - copied);
1878                                 if (!elem) {
1879                                         elem = kmalloc(desc->elem_size,
1880                                                        GFP_KERNEL);
1881                                         err = -ENOMEM;
1882                                         if (!elem)
1883                                                 goto out;
1884                                 }
1885                                 if (encode) {
1886                                         if (!copied) {
1887                                                 err = desc->xcode(desc, elem);
1888                                                 if (err)
1889                                                         goto out;
1890                                         }
1891                                         memcpy(c, elem + copied, l);
1892                                         copied += l;
1893                                         if (copied == desc->elem_size)
1894                                                 copied = 0;
1895                                 } else {
1896                                         memcpy(elem + copied, c, l);
1897                                         copied += l;
1898                                         if (copied == desc->elem_size) {
1899                                                 err = desc->xcode(desc, elem);
1900                                                 if (err)
1901                                                         goto out;
1902                                                 copied = 0;
1903                                         }
1904                                 }
1905                                 avail_page -= l;
1906                                 c += l;
1907                         }
1908                         while (avail_page >= desc->elem_size) {
1909                                 err = desc->xcode(desc, c);
1910                                 if (err)
1911                                         goto out;
1912                                 c += desc->elem_size;
1913                                 avail_page -= desc->elem_size;
1914                         }
1915                         if (avail_page) {
1916                                 unsigned int l = min(avail_page,
1917                                             desc->elem_size - copied);
1918                                 if (!elem) {
1919                                         elem = kmalloc(desc->elem_size,
1920                                                        GFP_KERNEL);
1921                                         err = -ENOMEM;
1922                                         if (!elem)
1923                                                 goto out;
1924                                 }
1925                                 if (encode) {
1926                                         if (!copied) {
1927                                                 err = desc->xcode(desc, elem);
1928                                                 if (err)
1929                                                         goto out;
1930                                         }
1931                                         memcpy(c, elem + copied, l);
1932                                         copied += l;
1933                                         if (copied == desc->elem_size)
1934                                                 copied = 0;
1935                                 } else {
1936                                         memcpy(elem + copied, c, l);
1937                                         copied += l;
1938                                         if (copied == desc->elem_size) {
1939                                                 err = desc->xcode(desc, elem);
1940                                                 if (err)
1941                                                         goto out;
1942                                                 copied = 0;
1943                                         }
1944                                 }
1945                         }
1946                         if (avail_here) {
1947                                 kunmap(*ppages);
1948                                 ppages++;
1949                                 c = kmap(*ppages);
1950                         }
1951 
1952                         avail_page = min(avail_here,
1953                                  (unsigned int) PAGE_SIZE);
1954                 }
1955                 base = buf->page_len;  /* align to start of tail */
1956         }
1957 
1958         /* process tail */
1959         base -= buf->page_len;
1960         if (todo) {
1961                 c = buf->tail->iov_base + base;
1962                 if (copied) {
1963                         unsigned int l = desc->elem_size - copied;
1964 
1965                         if (encode)
1966                                 memcpy(c, elem + copied, l);
1967                         else {
1968                                 memcpy(elem + copied, c, l);
1969                                 err = desc->xcode(desc, elem);
1970                                 if (err)
1971                                         goto out;
1972                         }
1973                         todo -= l;
1974                         c += l;
1975                 }
1976                 while (todo) {
1977                         err = desc->xcode(desc, c);
1978                         if (err)
1979                                 goto out;
1980                         c += desc->elem_size;
1981                         todo -= desc->elem_size;
1982                 }
1983         }
1984         err = 0;
1985 
1986 out:
1987         kfree(elem);
1988         if (ppages)
1989                 kunmap(*ppages);
1990         return err;
1991 }
1992 
1993 int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
1994                       struct xdr_array2_desc *desc)
1995 {
1996         if (base >= buf->len)
1997                 return -EINVAL;
1998 
1999         return xdr_xcode_array2(buf, base, desc, 0);
2000 }
2001 EXPORT_SYMBOL_GPL(xdr_decode_array2);
2002 
2003 int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
2004                       struct xdr_array2_desc *desc)
2005 {
2006         if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
2007             buf->head->iov_len + buf->page_len + buf->tail->iov_len)
2008                 return -EINVAL;
2009 
2010         return xdr_xcode_array2(buf, base, desc, 1);
2011 }
2012 EXPORT_SYMBOL_GPL(xdr_encode_array2);
2013 
2014 int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
2015                     unsigned int len,
2016                     int (*actor)(struct scatterlist *, void *), void *data)
2017 {
2018         int i, ret = 0;
2019         unsigned int page_len, thislen, page_offset;
2020         struct scatterlist      sg[1];
2021 
2022         sg_init_table(sg, 1);
2023 
2024         if (offset >= buf->head[0].iov_len) {
2025                 offset -= buf->head[0].iov_len;
2026         } else {
2027                 thislen = buf->head[0].iov_len - offset;
2028                 if (thislen > len)
2029                         thislen = len;
2030                 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
2031                 ret = actor(sg, data);
2032                 if (ret)
2033                         goto out;
2034                 offset = 0;
2035                 len -= thislen;
2036         }
2037         if (len == 0)
2038                 goto out;
2039 
2040         if (offset >= buf->page_len) {
2041                 offset -= buf->page_len;
2042         } else {
2043                 page_len = buf->page_len - offset;
2044                 if (page_len > len)
2045                         page_len = len;
2046                 len -= page_len;
2047                 page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
2048                 i = (offset + buf->page_base) >> PAGE_SHIFT;
2049                 thislen = PAGE_SIZE - page_offset;
2050                 do {
2051                         if (thislen > page_len)
2052                                 thislen = page_len;
2053                         sg_set_page(sg, buf->pages[i], thislen, page_offset);
2054                         ret = actor(sg, data);
2055                         if (ret)
2056                                 goto out;
2057                         page_len -= thislen;
2058                         i++;
2059                         page_offset = 0;
2060                         thislen = PAGE_SIZE;
2061                 } while (page_len != 0);
2062                 offset = 0;
2063         }
2064         if (len == 0)
2065                 goto out;
2066         if (offset < buf->tail[0].iov_len) {
2067                 thislen = buf->tail[0].iov_len - offset;
2068                 if (thislen > len)
2069                         thislen = len;
2070                 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
2071                 ret = actor(sg, data);
2072                 len -= thislen;
2073         }
2074         if (len != 0)
2075                 ret = -EINVAL;
2076 out:
2077         return ret;
2078 }
2079 EXPORT_SYMBOL_GPL(xdr_process_buf);
2080 
2081 /**
2082  * xdr_stream_decode_opaque - Decode variable length opaque
2083  * @xdr: pointer to xdr_stream
2084  * @ptr: location to store opaque data
2085  * @size: size of storage buffer @ptr
2086  *
2087  * Return values:
2088  *   On success, returns size of object stored in *@ptr
2089  *   %-EBADMSG on XDR buffer overflow
2090  *   %-EMSGSIZE on overflow of storage buffer @ptr
2091  */
2092 ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
2093 {
2094         ssize_t ret;
2095         void *p;
2096 
2097         ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2098         if (ret <= 0)
2099                 return ret;
2100         memcpy(ptr, p, ret);
2101         return ret;
2102 }
2103 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
2104 
2105 /**
2106  * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
2107  * @xdr: pointer to xdr_stream
2108  * @ptr: location to store pointer to opaque data
2109  * @maxlen: maximum acceptable object size
2110  * @gfp_flags: GFP mask to use
2111  *
2112  * Return values:
2113  *   On success, returns size of object stored in *@ptr
2114  *   %-EBADMSG on XDR buffer overflow
2115  *   %-EMSGSIZE if the size of the object would exceed @maxlen
2116  *   %-ENOMEM on memory allocation failure
2117  */
2118 ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
2119                 size_t maxlen, gfp_t gfp_flags)
2120 {
2121         ssize_t ret;
2122         void *p;
2123 
2124         ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2125         if (ret > 0) {
2126                 *ptr = kmemdup(p, ret, gfp_flags);
2127                 if (*ptr != NULL)
2128                         return ret;
2129                 ret = -ENOMEM;
2130         }
2131         *ptr = NULL;
2132         return ret;
2133 }
2134 EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
2135 
2136 /**
2137  * xdr_stream_decode_string - Decode variable length string
2138  * @xdr: pointer to xdr_stream
2139  * @str: location to store string
2140  * @size: size of storage buffer @str
2141  *
2142  * Return values:
2143  *   On success, returns length of NUL-terminated string stored in *@str
2144  *   %-EBADMSG on XDR buffer overflow
2145  *   %-EMSGSIZE on overflow of storage buffer @str
2146  */
2147 ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
2148 {
2149         ssize_t ret;
2150         void *p;
2151 
2152         ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
2153         if (ret > 0) {
2154                 memcpy(str, p, ret);
2155                 str[ret] = '\0';
2156                 return strlen(str);
2157         }
2158         *str = '\0';
2159         return ret;
2160 }
2161 EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
2162 
2163 /**
2164  * xdr_stream_decode_string_dup - Decode and duplicate variable length string
2165  * @xdr: pointer to xdr_stream
2166  * @str: location to store pointer to string
2167  * @maxlen: maximum acceptable string length
2168  * @gfp_flags: GFP mask to use
2169  *
2170  * Return values:
2171  *   On success, returns length of NUL-terminated string stored in *@ptr
2172  *   %-EBADMSG on XDR buffer overflow
2173  *   %-EMSGSIZE if the size of the string would exceed @maxlen
2174  *   %-ENOMEM on memory allocation failure
2175  */
2176 ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
2177                 size_t maxlen, gfp_t gfp_flags)
2178 {
2179         void *p;
2180         ssize_t ret;
2181 
2182         ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
2183         if (ret > 0) {
2184                 char *s = kmemdup_nul(p, ret, gfp_flags);
2185                 if (s != NULL) {
2186                         *str = s;
2187                         return strlen(s);
2188                 }
2189                 ret = -ENOMEM;
2190         }
2191         *str = NULL;
2192         return ret;
2193 }
2194 EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);
2195 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp