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TOMOYO Linux Cross Reference
Linux/net/sunrpc/xprtrdma/rpc_rdma.c

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  1 /*
  2  * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
  3  *
  4  * This software is available to you under a choice of one of two
  5  * licenses.  You may choose to be licensed under the terms of the GNU
  6  * General Public License (GPL) Version 2, available from the file
  7  * COPYING in the main directory of this source tree, or the BSD-type
  8  * license below:
  9  *
 10  * Redistribution and use in source and binary forms, with or without
 11  * modification, are permitted provided that the following conditions
 12  * are met:
 13  *
 14  *      Redistributions of source code must retain the above copyright
 15  *      notice, this list of conditions and the following disclaimer.
 16  *
 17  *      Redistributions in binary form must reproduce the above
 18  *      copyright notice, this list of conditions and the following
 19  *      disclaimer in the documentation and/or other materials provided
 20  *      with the distribution.
 21  *
 22  *      Neither the name of the Network Appliance, Inc. nor the names of
 23  *      its contributors may be used to endorse or promote products
 24  *      derived from this software without specific prior written
 25  *      permission.
 26  *
 27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 28  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 29  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 30  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 31  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 32  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 33  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 37  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 38  */
 39 
 40 /*
 41  * rpc_rdma.c
 42  *
 43  * This file contains the guts of the RPC RDMA protocol, and
 44  * does marshaling/unmarshaling, etc. It is also where interfacing
 45  * to the Linux RPC framework lives.
 46  */
 47 
 48 #include "xprt_rdma.h"
 49 
 50 #include <linux/highmem.h>
 51 
 52 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 53 # define RPCDBG_FACILITY        RPCDBG_TRANS
 54 #endif
 55 
 56 enum rpcrdma_chunktype {
 57         rpcrdma_noch = 0,
 58         rpcrdma_readch,
 59         rpcrdma_areadch,
 60         rpcrdma_writech,
 61         rpcrdma_replych
 62 };
 63 
 64 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 65 static const char transfertypes[][12] = {
 66         "pure inline",  /* no chunks */
 67         " read chunk",  /* some argument via rdma read */
 68         "*read chunk",  /* entire request via rdma read */
 69         "write chunk",  /* some result via rdma write */
 70         "reply chunk"   /* entire reply via rdma write */
 71 };
 72 #endif
 73 
 74 /*
 75  * Chunk assembly from upper layer xdr_buf.
 76  *
 77  * Prepare the passed-in xdr_buf into representation as RPC/RDMA chunk
 78  * elements. Segments are then coalesced when registered, if possible
 79  * within the selected memreg mode.
 80  *
 81  * Returns positive number of segments converted, or a negative errno.
 82  */
 83 
 84 static int
 85 rpcrdma_convert_iovs(struct xdr_buf *xdrbuf, unsigned int pos,
 86         enum rpcrdma_chunktype type, struct rpcrdma_mr_seg *seg, int nsegs)
 87 {
 88         int len, n = 0, p;
 89         int page_base;
 90         struct page **ppages;
 91 
 92         if (pos == 0 && xdrbuf->head[0].iov_len) {
 93                 seg[n].mr_page = NULL;
 94                 seg[n].mr_offset = xdrbuf->head[0].iov_base;
 95                 seg[n].mr_len = xdrbuf->head[0].iov_len;
 96                 ++n;
 97         }
 98 
 99         len = xdrbuf->page_len;
100         ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT);
101         page_base = xdrbuf->page_base & ~PAGE_MASK;
102         p = 0;
103         while (len && n < nsegs) {
104                 if (!ppages[p]) {
105                         /* alloc the pagelist for receiving buffer */
106                         ppages[p] = alloc_page(GFP_ATOMIC);
107                         if (!ppages[p])
108                                 return -ENOMEM;
109                 }
110                 seg[n].mr_page = ppages[p];
111                 seg[n].mr_offset = (void *)(unsigned long) page_base;
112                 seg[n].mr_len = min_t(u32, PAGE_SIZE - page_base, len);
113                 if (seg[n].mr_len > PAGE_SIZE)
114                         return -EIO;
115                 len -= seg[n].mr_len;
116                 ++n;
117                 ++p;
118                 page_base = 0;  /* page offset only applies to first page */
119         }
120 
121         /* Message overflows the seg array */
122         if (len && n == nsegs)
123                 return -EIO;
124 
125         if (xdrbuf->tail[0].iov_len) {
126                 /* the rpcrdma protocol allows us to omit any trailing
127                  * xdr pad bytes, saving the server an RDMA operation. */
128                 if (xdrbuf->tail[0].iov_len < 4 && xprt_rdma_pad_optimize)
129                         return n;
130                 if (n == nsegs)
131                         /* Tail remains, but we're out of segments */
132                         return -EIO;
133                 seg[n].mr_page = NULL;
134                 seg[n].mr_offset = xdrbuf->tail[0].iov_base;
135                 seg[n].mr_len = xdrbuf->tail[0].iov_len;
136                 ++n;
137         }
138 
139         return n;
140 }
141 
142 /*
143  * Create read/write chunk lists, and reply chunks, for RDMA
144  *
145  *   Assume check against THRESHOLD has been done, and chunks are required.
146  *   Assume only encoding one list entry for read|write chunks. The NFSv3
147  *     protocol is simple enough to allow this as it only has a single "bulk
148  *     result" in each procedure - complicated NFSv4 COMPOUNDs are not. (The
149  *     RDMA/Sessions NFSv4 proposal addresses this for future v4 revs.)
150  *
151  * When used for a single reply chunk (which is a special write
152  * chunk used for the entire reply, rather than just the data), it
153  * is used primarily for READDIR and READLINK which would otherwise
154  * be severely size-limited by a small rdma inline read max. The server
155  * response will come back as an RDMA Write, followed by a message
156  * of type RDMA_NOMSG carrying the xid and length. As a result, reply
157  * chunks do not provide data alignment, however they do not require
158  * "fixup" (moving the response to the upper layer buffer) either.
159  *
160  * Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
161  *
162  *  Read chunklist (a linked list):
163  *   N elements, position P (same P for all chunks of same arg!):
164  *    1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
165  *
166  *  Write chunklist (a list of (one) counted array):
167  *   N elements:
168  *    1 - N - HLOO - HLOO - ... - HLOO - 0
169  *
170  *  Reply chunk (a counted array):
171  *   N elements:
172  *    1 - N - HLOO - HLOO - ... - HLOO
173  *
174  * Returns positive RPC/RDMA header size, or negative errno.
175  */
176 
177 static ssize_t
178 rpcrdma_create_chunks(struct rpc_rqst *rqst, struct xdr_buf *target,
179                 struct rpcrdma_msg *headerp, enum rpcrdma_chunktype type)
180 {
181         struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
182         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
183         int n, nsegs, nchunks = 0;
184         unsigned int pos;
185         struct rpcrdma_mr_seg *seg = req->rl_segments;
186         struct rpcrdma_read_chunk *cur_rchunk = NULL;
187         struct rpcrdma_write_array *warray = NULL;
188         struct rpcrdma_write_chunk *cur_wchunk = NULL;
189         __be32 *iptr = headerp->rm_body.rm_chunks;
190         int (*map)(struct rpcrdma_xprt *, struct rpcrdma_mr_seg *, int, bool);
191 
192         if (type == rpcrdma_readch || type == rpcrdma_areadch) {
193                 /* a read chunk - server will RDMA Read our memory */
194                 cur_rchunk = (struct rpcrdma_read_chunk *) iptr;
195         } else {
196                 /* a write or reply chunk - server will RDMA Write our memory */
197                 *iptr++ = xdr_zero;     /* encode a NULL read chunk list */
198                 if (type == rpcrdma_replych)
199                         *iptr++ = xdr_zero;     /* a NULL write chunk list */
200                 warray = (struct rpcrdma_write_array *) iptr;
201                 cur_wchunk = (struct rpcrdma_write_chunk *) (warray + 1);
202         }
203 
204         if (type == rpcrdma_replych || type == rpcrdma_areadch)
205                 pos = 0;
206         else
207                 pos = target->head[0].iov_len;
208 
209         nsegs = rpcrdma_convert_iovs(target, pos, type, seg, RPCRDMA_MAX_SEGS);
210         if (nsegs < 0)
211                 return nsegs;
212 
213         map = r_xprt->rx_ia.ri_ops->ro_map;
214         do {
215                 n = map(r_xprt, seg, nsegs, cur_wchunk != NULL);
216                 if (n <= 0)
217                         goto out;
218                 if (cur_rchunk) {       /* read */
219                         cur_rchunk->rc_discrim = xdr_one;
220                         /* all read chunks have the same "position" */
221                         cur_rchunk->rc_position = cpu_to_be32(pos);
222                         cur_rchunk->rc_target.rs_handle =
223                                                 cpu_to_be32(seg->mr_rkey);
224                         cur_rchunk->rc_target.rs_length =
225                                                 cpu_to_be32(seg->mr_len);
226                         xdr_encode_hyper(
227                                         (__be32 *)&cur_rchunk->rc_target.rs_offset,
228                                         seg->mr_base);
229                         dprintk("RPC:       %s: read chunk "
230                                 "elem %d@0x%llx:0x%x pos %u (%s)\n", __func__,
231                                 seg->mr_len, (unsigned long long)seg->mr_base,
232                                 seg->mr_rkey, pos, n < nsegs ? "more" : "last");
233                         cur_rchunk++;
234                         r_xprt->rx_stats.read_chunk_count++;
235                 } else {                /* write/reply */
236                         cur_wchunk->wc_target.rs_handle =
237                                                 cpu_to_be32(seg->mr_rkey);
238                         cur_wchunk->wc_target.rs_length =
239                                                 cpu_to_be32(seg->mr_len);
240                         xdr_encode_hyper(
241                                         (__be32 *)&cur_wchunk->wc_target.rs_offset,
242                                         seg->mr_base);
243                         dprintk("RPC:       %s: %s chunk "
244                                 "elem %d@0x%llx:0x%x (%s)\n", __func__,
245                                 (type == rpcrdma_replych) ? "reply" : "write",
246                                 seg->mr_len, (unsigned long long)seg->mr_base,
247                                 seg->mr_rkey, n < nsegs ? "more" : "last");
248                         cur_wchunk++;
249                         if (type == rpcrdma_replych)
250                                 r_xprt->rx_stats.reply_chunk_count++;
251                         else
252                                 r_xprt->rx_stats.write_chunk_count++;
253                         r_xprt->rx_stats.total_rdma_request += seg->mr_len;
254                 }
255                 nchunks++;
256                 seg   += n;
257                 nsegs -= n;
258         } while (nsegs);
259 
260         /* success. all failures return above */
261         req->rl_nchunks = nchunks;
262 
263         /*
264          * finish off header. If write, marshal discrim and nchunks.
265          */
266         if (cur_rchunk) {
267                 iptr = (__be32 *) cur_rchunk;
268                 *iptr++ = xdr_zero;     /* finish the read chunk list */
269                 *iptr++ = xdr_zero;     /* encode a NULL write chunk list */
270                 *iptr++ = xdr_zero;     /* encode a NULL reply chunk */
271         } else {
272                 warray->wc_discrim = xdr_one;
273                 warray->wc_nchunks = cpu_to_be32(nchunks);
274                 iptr = (__be32 *) cur_wchunk;
275                 if (type == rpcrdma_writech) {
276                         *iptr++ = xdr_zero; /* finish the write chunk list */
277                         *iptr++ = xdr_zero; /* encode a NULL reply chunk */
278                 }
279         }
280 
281         /*
282          * Return header size.
283          */
284         return (unsigned char *)iptr - (unsigned char *)headerp;
285 
286 out:
287         if (r_xprt->rx_ia.ri_memreg_strategy == RPCRDMA_FRMR)
288                 return n;
289 
290         for (pos = 0; nchunks--;)
291                 pos += r_xprt->rx_ia.ri_ops->ro_unmap(r_xprt,
292                                                       &req->rl_segments[pos]);
293         return n;
294 }
295 
296 /*
297  * Copy write data inline.
298  * This function is used for "small" requests. Data which is passed
299  * to RPC via iovecs (or page list) is copied directly into the
300  * pre-registered memory buffer for this request. For small amounts
301  * of data, this is efficient. The cutoff value is tunable.
302  */
303 static int
304 rpcrdma_inline_pullup(struct rpc_rqst *rqst, int pad)
305 {
306         int i, npages, curlen;
307         int copy_len;
308         unsigned char *srcp, *destp;
309         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(rqst->rq_xprt);
310         int page_base;
311         struct page **ppages;
312 
313         destp = rqst->rq_svec[0].iov_base;
314         curlen = rqst->rq_svec[0].iov_len;
315         destp += curlen;
316         /*
317          * Do optional padding where it makes sense. Alignment of write
318          * payload can help the server, if our setting is accurate.
319          */
320         pad -= (curlen + 36/*sizeof(struct rpcrdma_msg_padded)*/);
321         if (pad < 0 || rqst->rq_slen - curlen < RPCRDMA_INLINE_PAD_THRESH)
322                 pad = 0;        /* don't pad this request */
323 
324         dprintk("RPC:       %s: pad %d destp 0x%p len %d hdrlen %d\n",
325                 __func__, pad, destp, rqst->rq_slen, curlen);
326 
327         copy_len = rqst->rq_snd_buf.page_len;
328 
329         if (rqst->rq_snd_buf.tail[0].iov_len) {
330                 curlen = rqst->rq_snd_buf.tail[0].iov_len;
331                 if (destp + copy_len != rqst->rq_snd_buf.tail[0].iov_base) {
332                         memmove(destp + copy_len,
333                                 rqst->rq_snd_buf.tail[0].iov_base, curlen);
334                         r_xprt->rx_stats.pullup_copy_count += curlen;
335                 }
336                 dprintk("RPC:       %s: tail destp 0x%p len %d\n",
337                         __func__, destp + copy_len, curlen);
338                 rqst->rq_svec[0].iov_len += curlen;
339         }
340         r_xprt->rx_stats.pullup_copy_count += copy_len;
341 
342         page_base = rqst->rq_snd_buf.page_base;
343         ppages = rqst->rq_snd_buf.pages + (page_base >> PAGE_SHIFT);
344         page_base &= ~PAGE_MASK;
345         npages = PAGE_ALIGN(page_base+copy_len) >> PAGE_SHIFT;
346         for (i = 0; copy_len && i < npages; i++) {
347                 curlen = PAGE_SIZE - page_base;
348                 if (curlen > copy_len)
349                         curlen = copy_len;
350                 dprintk("RPC:       %s: page %d destp 0x%p len %d curlen %d\n",
351                         __func__, i, destp, copy_len, curlen);
352                 srcp = kmap_atomic(ppages[i]);
353                 memcpy(destp, srcp+page_base, curlen);
354                 kunmap_atomic(srcp);
355                 rqst->rq_svec[0].iov_len += curlen;
356                 destp += curlen;
357                 copy_len -= curlen;
358                 page_base = 0;
359         }
360         /* header now contains entire send message */
361         return pad;
362 }
363 
364 /*
365  * Marshal a request: the primary job of this routine is to choose
366  * the transfer modes. See comments below.
367  *
368  * Uses multiple RDMA IOVs for a request:
369  *  [0] -- RPC RDMA header, which uses memory from the *start* of the
370  *         preregistered buffer that already holds the RPC data in
371  *         its middle.
372  *  [1] -- the RPC header/data, marshaled by RPC and the NFS protocol.
373  *  [2] -- optional padding.
374  *  [3] -- if padded, header only in [1] and data here.
375  *
376  * Returns zero on success, otherwise a negative errno.
377  */
378 
379 int
380 rpcrdma_marshal_req(struct rpc_rqst *rqst)
381 {
382         struct rpc_xprt *xprt = rqst->rq_xprt;
383         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
384         struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
385         char *base;
386         size_t rpclen, padlen;
387         ssize_t hdrlen;
388         enum rpcrdma_chunktype rtype, wtype;
389         struct rpcrdma_msg *headerp;
390 
391         /*
392          * rpclen gets amount of data in first buffer, which is the
393          * pre-registered buffer.
394          */
395         base = rqst->rq_svec[0].iov_base;
396         rpclen = rqst->rq_svec[0].iov_len;
397 
398         headerp = rdmab_to_msg(req->rl_rdmabuf);
399         /* don't byte-swap XID, it's already done in request */
400         headerp->rm_xid = rqst->rq_xid;
401         headerp->rm_vers = rpcrdma_version;
402         headerp->rm_credit = cpu_to_be32(r_xprt->rx_buf.rb_max_requests);
403         headerp->rm_type = rdma_msg;
404 
405         /*
406          * Chunks needed for results?
407          *
408          * o If the expected result is under the inline threshold, all ops
409          *   return as inline (but see later).
410          * o Large non-read ops return as a single reply chunk.
411          * o Large read ops return data as write chunk(s), header as inline.
412          *
413          * Note: the NFS code sending down multiple result segments implies
414          * the op is one of read, readdir[plus], readlink or NFSv4 getacl.
415          */
416 
417         /*
418          * This code can handle read chunks, write chunks OR reply
419          * chunks -- only one type. If the request is too big to fit
420          * inline, then we will choose read chunks. If the request is
421          * a READ, then use write chunks to separate the file data
422          * into pages; otherwise use reply chunks.
423          */
424         if (rqst->rq_rcv_buf.buflen <= RPCRDMA_INLINE_READ_THRESHOLD(rqst))
425                 wtype = rpcrdma_noch;
426         else if (rqst->rq_rcv_buf.page_len == 0)
427                 wtype = rpcrdma_replych;
428         else if (rqst->rq_rcv_buf.flags & XDRBUF_READ)
429                 wtype = rpcrdma_writech;
430         else
431                 wtype = rpcrdma_replych;
432 
433         /*
434          * Chunks needed for arguments?
435          *
436          * o If the total request is under the inline threshold, all ops
437          *   are sent as inline.
438          * o Large non-write ops are sent with the entire message as a
439          *   single read chunk (protocol 0-position special case).
440          * o Large write ops transmit data as read chunk(s), header as
441          *   inline.
442          *
443          * Note: the NFS code sending down multiple argument segments
444          * implies the op is a write.
445          * TBD check NFSv4 setacl
446          */
447         if (rqst->rq_snd_buf.len <= RPCRDMA_INLINE_WRITE_THRESHOLD(rqst))
448                 rtype = rpcrdma_noch;
449         else if (rqst->rq_snd_buf.page_len == 0)
450                 rtype = rpcrdma_areadch;
451         else
452                 rtype = rpcrdma_readch;
453 
454         /* The following simplification is not true forever */
455         if (rtype != rpcrdma_noch && wtype == rpcrdma_replych)
456                 wtype = rpcrdma_noch;
457         if (rtype != rpcrdma_noch && wtype != rpcrdma_noch) {
458                 dprintk("RPC:       %s: cannot marshal multiple chunk lists\n",
459                         __func__);
460                 return -EIO;
461         }
462 
463         hdrlen = RPCRDMA_HDRLEN_MIN;
464         padlen = 0;
465 
466         /*
467          * Pull up any extra send data into the preregistered buffer.
468          * When padding is in use and applies to the transfer, insert
469          * it and change the message type.
470          */
471         if (rtype == rpcrdma_noch) {
472 
473                 padlen = rpcrdma_inline_pullup(rqst,
474                                                 RPCRDMA_INLINE_PAD_VALUE(rqst));
475 
476                 if (padlen) {
477                         headerp->rm_type = rdma_msgp;
478                         headerp->rm_body.rm_padded.rm_align =
479                                 cpu_to_be32(RPCRDMA_INLINE_PAD_VALUE(rqst));
480                         headerp->rm_body.rm_padded.rm_thresh =
481                                 cpu_to_be32(RPCRDMA_INLINE_PAD_THRESH);
482                         headerp->rm_body.rm_padded.rm_pempty[0] = xdr_zero;
483                         headerp->rm_body.rm_padded.rm_pempty[1] = xdr_zero;
484                         headerp->rm_body.rm_padded.rm_pempty[2] = xdr_zero;
485                         hdrlen += 2 * sizeof(u32); /* extra words in padhdr */
486                         if (wtype != rpcrdma_noch) {
487                                 dprintk("RPC:       %s: invalid chunk list\n",
488                                         __func__);
489                                 return -EIO;
490                         }
491                 } else {
492                         headerp->rm_body.rm_nochunks.rm_empty[0] = xdr_zero;
493                         headerp->rm_body.rm_nochunks.rm_empty[1] = xdr_zero;
494                         headerp->rm_body.rm_nochunks.rm_empty[2] = xdr_zero;
495                         /* new length after pullup */
496                         rpclen = rqst->rq_svec[0].iov_len;
497                         /*
498                          * Currently we try to not actually use read inline.
499                          * Reply chunks have the desirable property that
500                          * they land, packed, directly in the target buffers
501                          * without headers, so they require no fixup. The
502                          * additional RDMA Write op sends the same amount
503                          * of data, streams on-the-wire and adds no overhead
504                          * on receive. Therefore, we request a reply chunk
505                          * for non-writes wherever feasible and efficient.
506                          */
507                         if (wtype == rpcrdma_noch)
508                                 wtype = rpcrdma_replych;
509                 }
510         }
511 
512         if (rtype != rpcrdma_noch) {
513                 hdrlen = rpcrdma_create_chunks(rqst, &rqst->rq_snd_buf,
514                                                headerp, rtype);
515                 wtype = rtype;  /* simplify dprintk */
516 
517         } else if (wtype != rpcrdma_noch) {
518                 hdrlen = rpcrdma_create_chunks(rqst, &rqst->rq_rcv_buf,
519                                                headerp, wtype);
520         }
521         if (hdrlen < 0)
522                 return hdrlen;
523 
524         dprintk("RPC:       %s: %s: hdrlen %zd rpclen %zd padlen %zd"
525                 " headerp 0x%p base 0x%p lkey 0x%x\n",
526                 __func__, transfertypes[wtype], hdrlen, rpclen, padlen,
527                 headerp, base, rdmab_lkey(req->rl_rdmabuf));
528 
529         /*
530          * initialize send_iov's - normally only two: rdma chunk header and
531          * single preregistered RPC header buffer, but if padding is present,
532          * then use a preregistered (and zeroed) pad buffer between the RPC
533          * header and any write data. In all non-rdma cases, any following
534          * data has been copied into the RPC header buffer.
535          */
536         req->rl_send_iov[0].addr = rdmab_addr(req->rl_rdmabuf);
537         req->rl_send_iov[0].length = hdrlen;
538         req->rl_send_iov[0].lkey = rdmab_lkey(req->rl_rdmabuf);
539 
540         req->rl_send_iov[1].addr = rdmab_addr(req->rl_sendbuf);
541         req->rl_send_iov[1].length = rpclen;
542         req->rl_send_iov[1].lkey = rdmab_lkey(req->rl_sendbuf);
543 
544         req->rl_niovs = 2;
545 
546         if (padlen) {
547                 struct rpcrdma_ep *ep = &r_xprt->rx_ep;
548 
549                 req->rl_send_iov[2].addr = rdmab_addr(ep->rep_padbuf);
550                 req->rl_send_iov[2].length = padlen;
551                 req->rl_send_iov[2].lkey = rdmab_lkey(ep->rep_padbuf);
552 
553                 req->rl_send_iov[3].addr = req->rl_send_iov[1].addr + rpclen;
554                 req->rl_send_iov[3].length = rqst->rq_slen - rpclen;
555                 req->rl_send_iov[3].lkey = rdmab_lkey(req->rl_sendbuf);
556 
557                 req->rl_niovs = 4;
558         }
559 
560         return 0;
561 }
562 
563 /*
564  * Chase down a received write or reply chunklist to get length
565  * RDMA'd by server. See map at rpcrdma_create_chunks()! :-)
566  */
567 static int
568 rpcrdma_count_chunks(struct rpcrdma_rep *rep, unsigned int max, int wrchunk, __be32 **iptrp)
569 {
570         unsigned int i, total_len;
571         struct rpcrdma_write_chunk *cur_wchunk;
572         char *base = (char *)rdmab_to_msg(rep->rr_rdmabuf);
573 
574         i = be32_to_cpu(**iptrp);
575         if (i > max)
576                 return -1;
577         cur_wchunk = (struct rpcrdma_write_chunk *) (*iptrp + 1);
578         total_len = 0;
579         while (i--) {
580                 struct rpcrdma_segment *seg = &cur_wchunk->wc_target;
581                 ifdebug(FACILITY) {
582                         u64 off;
583                         xdr_decode_hyper((__be32 *)&seg->rs_offset, &off);
584                         dprintk("RPC:       %s: chunk %d@0x%llx:0x%x\n",
585                                 __func__,
586                                 be32_to_cpu(seg->rs_length),
587                                 (unsigned long long)off,
588                                 be32_to_cpu(seg->rs_handle));
589                 }
590                 total_len += be32_to_cpu(seg->rs_length);
591                 ++cur_wchunk;
592         }
593         /* check and adjust for properly terminated write chunk */
594         if (wrchunk) {
595                 __be32 *w = (__be32 *) cur_wchunk;
596                 if (*w++ != xdr_zero)
597                         return -1;
598                 cur_wchunk = (struct rpcrdma_write_chunk *) w;
599         }
600         if ((char *)cur_wchunk > base + rep->rr_len)
601                 return -1;
602 
603         *iptrp = (__be32 *) cur_wchunk;
604         return total_len;
605 }
606 
607 /*
608  * Scatter inline received data back into provided iov's.
609  */
610 static void
611 rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
612 {
613         int i, npages, curlen, olen;
614         char *destp;
615         struct page **ppages;
616         int page_base;
617 
618         curlen = rqst->rq_rcv_buf.head[0].iov_len;
619         if (curlen > copy_len) {        /* write chunk header fixup */
620                 curlen = copy_len;
621                 rqst->rq_rcv_buf.head[0].iov_len = curlen;
622         }
623 
624         dprintk("RPC:       %s: srcp 0x%p len %d hdrlen %d\n",
625                 __func__, srcp, copy_len, curlen);
626 
627         /* Shift pointer for first receive segment only */
628         rqst->rq_rcv_buf.head[0].iov_base = srcp;
629         srcp += curlen;
630         copy_len -= curlen;
631 
632         olen = copy_len;
633         i = 0;
634         rpcx_to_rdmax(rqst->rq_xprt)->rx_stats.fixup_copy_count += olen;
635         page_base = rqst->rq_rcv_buf.page_base;
636         ppages = rqst->rq_rcv_buf.pages + (page_base >> PAGE_SHIFT);
637         page_base &= ~PAGE_MASK;
638 
639         if (copy_len && rqst->rq_rcv_buf.page_len) {
640                 npages = PAGE_ALIGN(page_base +
641                         rqst->rq_rcv_buf.page_len) >> PAGE_SHIFT;
642                 for (; i < npages; i++) {
643                         curlen = PAGE_SIZE - page_base;
644                         if (curlen > copy_len)
645                                 curlen = copy_len;
646                         dprintk("RPC:       %s: page %d"
647                                 " srcp 0x%p len %d curlen %d\n",
648                                 __func__, i, srcp, copy_len, curlen);
649                         destp = kmap_atomic(ppages[i]);
650                         memcpy(destp + page_base, srcp, curlen);
651                         flush_dcache_page(ppages[i]);
652                         kunmap_atomic(destp);
653                         srcp += curlen;
654                         copy_len -= curlen;
655                         if (copy_len == 0)
656                                 break;
657                         page_base = 0;
658                 }
659         }
660 
661         if (copy_len && rqst->rq_rcv_buf.tail[0].iov_len) {
662                 curlen = copy_len;
663                 if (curlen > rqst->rq_rcv_buf.tail[0].iov_len)
664                         curlen = rqst->rq_rcv_buf.tail[0].iov_len;
665                 if (rqst->rq_rcv_buf.tail[0].iov_base != srcp)
666                         memmove(rqst->rq_rcv_buf.tail[0].iov_base, srcp, curlen);
667                 dprintk("RPC:       %s: tail srcp 0x%p len %d curlen %d\n",
668                         __func__, srcp, copy_len, curlen);
669                 rqst->rq_rcv_buf.tail[0].iov_len = curlen;
670                 copy_len -= curlen; ++i;
671         } else
672                 rqst->rq_rcv_buf.tail[0].iov_len = 0;
673 
674         if (pad) {
675                 /* implicit padding on terminal chunk */
676                 unsigned char *p = rqst->rq_rcv_buf.tail[0].iov_base;
677                 while (pad--)
678                         p[rqst->rq_rcv_buf.tail[0].iov_len++] = 0;
679         }
680 
681         if (copy_len)
682                 dprintk("RPC:       %s: %d bytes in"
683                         " %d extra segments (%d lost)\n",
684                         __func__, olen, i, copy_len);
685 
686         /* TBD avoid a warning from call_decode() */
687         rqst->rq_private_buf = rqst->rq_rcv_buf;
688 }
689 
690 void
691 rpcrdma_connect_worker(struct work_struct *work)
692 {
693         struct rpcrdma_ep *ep =
694                 container_of(work, struct rpcrdma_ep, rep_connect_worker.work);
695         struct rpcrdma_xprt *r_xprt =
696                 container_of(ep, struct rpcrdma_xprt, rx_ep);
697         struct rpc_xprt *xprt = &r_xprt->rx_xprt;
698 
699         spin_lock_bh(&xprt->transport_lock);
700         if (++xprt->connect_cookie == 0)        /* maintain a reserved value */
701                 ++xprt->connect_cookie;
702         if (ep->rep_connected > 0) {
703                 if (!xprt_test_and_set_connected(xprt))
704                         xprt_wake_pending_tasks(xprt, 0);
705         } else {
706                 if (xprt_test_and_clear_connected(xprt))
707                         xprt_wake_pending_tasks(xprt, -ENOTCONN);
708         }
709         spin_unlock_bh(&xprt->transport_lock);
710 }
711 
712 /*
713  * This function is called when an async event is posted to
714  * the connection which changes the connection state. All it
715  * does at this point is mark the connection up/down, the rpc
716  * timers do the rest.
717  */
718 void
719 rpcrdma_conn_func(struct rpcrdma_ep *ep)
720 {
721         schedule_delayed_work(&ep->rep_connect_worker, 0);
722 }
723 
724 /*
725  * Called as a tasklet to do req/reply match and complete a request
726  * Errors must result in the RPC task either being awakened, or
727  * allowed to timeout, to discover the errors at that time.
728  */
729 void
730 rpcrdma_reply_handler(struct rpcrdma_rep *rep)
731 {
732         struct rpcrdma_msg *headerp;
733         struct rpcrdma_req *req;
734         struct rpc_rqst *rqst;
735         struct rpc_xprt *xprt = rep->rr_xprt;
736         struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
737         __be32 *iptr;
738         int rdmalen, status;
739         unsigned long cwnd;
740         u32 credits;
741 
742         /* Check status. If bad, signal disconnect and return rep to pool */
743         if (rep->rr_len == ~0U) {
744                 rpcrdma_recv_buffer_put(rep);
745                 if (r_xprt->rx_ep.rep_connected == 1) {
746                         r_xprt->rx_ep.rep_connected = -EIO;
747                         rpcrdma_conn_func(&r_xprt->rx_ep);
748                 }
749                 return;
750         }
751         if (rep->rr_len < RPCRDMA_HDRLEN_MIN) {
752                 dprintk("RPC:       %s: short/invalid reply\n", __func__);
753                 goto repost;
754         }
755         headerp = rdmab_to_msg(rep->rr_rdmabuf);
756         if (headerp->rm_vers != rpcrdma_version) {
757                 dprintk("RPC:       %s: invalid version %d\n",
758                         __func__, be32_to_cpu(headerp->rm_vers));
759                 goto repost;
760         }
761 
762         /* Get XID and try for a match. */
763         spin_lock(&xprt->transport_lock);
764         rqst = xprt_lookup_rqst(xprt, headerp->rm_xid);
765         if (rqst == NULL) {
766                 spin_unlock(&xprt->transport_lock);
767                 dprintk("RPC:       %s: reply 0x%p failed "
768                         "to match any request xid 0x%08x len %d\n",
769                         __func__, rep, be32_to_cpu(headerp->rm_xid),
770                         rep->rr_len);
771 repost:
772                 r_xprt->rx_stats.bad_reply_count++;
773                 rep->rr_func = rpcrdma_reply_handler;
774                 if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, &r_xprt->rx_ep, rep))
775                         rpcrdma_recv_buffer_put(rep);
776 
777                 return;
778         }
779 
780         /* get request object */
781         req = rpcr_to_rdmar(rqst);
782         if (req->rl_reply) {
783                 spin_unlock(&xprt->transport_lock);
784                 dprintk("RPC:       %s: duplicate reply 0x%p to RPC "
785                         "request 0x%p: xid 0x%08x\n", __func__, rep, req,
786                         be32_to_cpu(headerp->rm_xid));
787                 goto repost;
788         }
789 
790         dprintk("RPC:       %s: reply 0x%p completes request 0x%p\n"
791                 "                   RPC request 0x%p xid 0x%08x\n",
792                         __func__, rep, req, rqst,
793                         be32_to_cpu(headerp->rm_xid));
794 
795         /* from here on, the reply is no longer an orphan */
796         req->rl_reply = rep;
797         xprt->reestablish_timeout = 0;
798 
799         /* check for expected message types */
800         /* The order of some of these tests is important. */
801         switch (headerp->rm_type) {
802         case rdma_msg:
803                 /* never expect read chunks */
804                 /* never expect reply chunks (two ways to check) */
805                 /* never expect write chunks without having offered RDMA */
806                 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
807                     (headerp->rm_body.rm_chunks[1] == xdr_zero &&
808                      headerp->rm_body.rm_chunks[2] != xdr_zero) ||
809                     (headerp->rm_body.rm_chunks[1] != xdr_zero &&
810                      req->rl_nchunks == 0))
811                         goto badheader;
812                 if (headerp->rm_body.rm_chunks[1] != xdr_zero) {
813                         /* count any expected write chunks in read reply */
814                         /* start at write chunk array count */
815                         iptr = &headerp->rm_body.rm_chunks[2];
816                         rdmalen = rpcrdma_count_chunks(rep,
817                                                 req->rl_nchunks, 1, &iptr);
818                         /* check for validity, and no reply chunk after */
819                         if (rdmalen < 0 || *iptr++ != xdr_zero)
820                                 goto badheader;
821                         rep->rr_len -=
822                             ((unsigned char *)iptr - (unsigned char *)headerp);
823                         status = rep->rr_len + rdmalen;
824                         r_xprt->rx_stats.total_rdma_reply += rdmalen;
825                         /* special case - last chunk may omit padding */
826                         if (rdmalen &= 3) {
827                                 rdmalen = 4 - rdmalen;
828                                 status += rdmalen;
829                         }
830                 } else {
831                         /* else ordinary inline */
832                         rdmalen = 0;
833                         iptr = (__be32 *)((unsigned char *)headerp +
834                                                         RPCRDMA_HDRLEN_MIN);
835                         rep->rr_len -= RPCRDMA_HDRLEN_MIN;
836                         status = rep->rr_len;
837                 }
838                 /* Fix up the rpc results for upper layer */
839                 rpcrdma_inline_fixup(rqst, (char *)iptr, rep->rr_len, rdmalen);
840                 break;
841 
842         case rdma_nomsg:
843                 /* never expect read or write chunks, always reply chunks */
844                 if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
845                     headerp->rm_body.rm_chunks[1] != xdr_zero ||
846                     headerp->rm_body.rm_chunks[2] != xdr_one ||
847                     req->rl_nchunks == 0)
848                         goto badheader;
849                 iptr = (__be32 *)((unsigned char *)headerp +
850                                                         RPCRDMA_HDRLEN_MIN);
851                 rdmalen = rpcrdma_count_chunks(rep, req->rl_nchunks, 0, &iptr);
852                 if (rdmalen < 0)
853                         goto badheader;
854                 r_xprt->rx_stats.total_rdma_reply += rdmalen;
855                 /* Reply chunk buffer already is the reply vector - no fixup. */
856                 status = rdmalen;
857                 break;
858 
859 badheader:
860         default:
861                 dprintk("%s: invalid rpcrdma reply header (type %d):"
862                                 " chunks[012] == %d %d %d"
863                                 " expected chunks <= %d\n",
864                                 __func__, be32_to_cpu(headerp->rm_type),
865                                 headerp->rm_body.rm_chunks[0],
866                                 headerp->rm_body.rm_chunks[1],
867                                 headerp->rm_body.rm_chunks[2],
868                                 req->rl_nchunks);
869                 status = -EIO;
870                 r_xprt->rx_stats.bad_reply_count++;
871                 break;
872         }
873 
874         credits = be32_to_cpu(headerp->rm_credit);
875         if (credits == 0)
876                 credits = 1;    /* don't deadlock */
877         else if (credits > r_xprt->rx_buf.rb_max_requests)
878                 credits = r_xprt->rx_buf.rb_max_requests;
879 
880         cwnd = xprt->cwnd;
881         xprt->cwnd = credits << RPC_CWNDSHIFT;
882         if (xprt->cwnd > cwnd)
883                 xprt_release_rqst_cong(rqst->rq_task);
884 
885         dprintk("RPC:       %s: xprt_complete_rqst(0x%p, 0x%p, %d)\n",
886                         __func__, xprt, rqst, status);
887         xprt_complete_rqst(rqst->rq_task, status);
888         spin_unlock(&xprt->transport_lock);
889 }
890 

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