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

TOMOYO Linux Cross Reference
Linux/net/rds/ib_send.c

Version: ~ [ linux-5.13-rc1 ] ~ [ linux-5.12.2 ] ~ [ linux-5.11.19 ] ~ [ linux-5.10.35 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.117 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.190 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.232 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.268 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.268 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Copyright (c) 2006 Oracle.  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
  8  * OpenIB.org BSD license below:
  9  *
 10  *     Redistribution and use in source and binary forms, with or
 11  *     without modification, are permitted provided that the following
 12  *     conditions are met:
 13  *
 14  *      - Redistributions of source code must retain the above
 15  *        copyright notice, this list of conditions and the following
 16  *        disclaimer.
 17  *
 18  *      - Redistributions in binary form must reproduce the above
 19  *        copyright notice, this list of conditions and the following
 20  *        disclaimer in the documentation and/or other materials
 21  *        provided with the distribution.
 22  *
 23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 30  * SOFTWARE.
 31  *
 32  */
 33 #include <linux/kernel.h>
 34 #include <linux/in.h>
 35 #include <linux/device.h>
 36 #include <linux/dmapool.h>
 37 #include <linux/ratelimit.h>
 38 
 39 #include "rds_single_path.h"
 40 #include "rds.h"
 41 #include "ib.h"
 42 
 43 /*
 44  * Convert IB-specific error message to RDS error message and call core
 45  * completion handler.
 46  */
 47 static void rds_ib_send_complete(struct rds_message *rm,
 48                                  int wc_status,
 49                                  void (*complete)(struct rds_message *rm, int status))
 50 {
 51         int notify_status;
 52 
 53         switch (wc_status) {
 54         case IB_WC_WR_FLUSH_ERR:
 55                 return;
 56 
 57         case IB_WC_SUCCESS:
 58                 notify_status = RDS_RDMA_SUCCESS;
 59                 break;
 60 
 61         case IB_WC_REM_ACCESS_ERR:
 62                 notify_status = RDS_RDMA_REMOTE_ERROR;
 63                 break;
 64 
 65         default:
 66                 notify_status = RDS_RDMA_OTHER_ERROR;
 67                 break;
 68         }
 69         complete(rm, notify_status);
 70 }
 71 
 72 static void rds_ib_send_unmap_rdma(struct rds_ib_connection *ic,
 73                                    struct rm_rdma_op *op,
 74                                    int wc_status)
 75 {
 76         if (op->op_mapped) {
 77                 ib_dma_unmap_sg(ic->i_cm_id->device,
 78                                 op->op_sg, op->op_nents,
 79                                 op->op_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
 80                 op->op_mapped = 0;
 81         }
 82 
 83         /* If the user asked for a completion notification on this
 84          * message, we can implement three different semantics:
 85          *  1.  Notify when we received the ACK on the RDS message
 86          *      that was queued with the RDMA. This provides reliable
 87          *      notification of RDMA status at the expense of a one-way
 88          *      packet delay.
 89          *  2.  Notify when the IB stack gives us the completion event for
 90          *      the RDMA operation.
 91          *  3.  Notify when the IB stack gives us the completion event for
 92          *      the accompanying RDS messages.
 93          * Here, we implement approach #3. To implement approach #2,
 94          * we would need to take an event for the rdma WR. To implement #1,
 95          * don't call rds_rdma_send_complete at all, and fall back to the notify
 96          * handling in the ACK processing code.
 97          *
 98          * Note: There's no need to explicitly sync any RDMA buffers using
 99          * ib_dma_sync_sg_for_cpu - the completion for the RDMA
100          * operation itself unmapped the RDMA buffers, which takes care
101          * of synching.
102          */
103         rds_ib_send_complete(container_of(op, struct rds_message, rdma),
104                              wc_status, rds_rdma_send_complete);
105 
106         if (op->op_write)
107                 rds_stats_add(s_send_rdma_bytes, op->op_bytes);
108         else
109                 rds_stats_add(s_recv_rdma_bytes, op->op_bytes);
110 }
111 
112 static void rds_ib_send_unmap_atomic(struct rds_ib_connection *ic,
113                                      struct rm_atomic_op *op,
114                                      int wc_status)
115 {
116         /* unmap atomic recvbuf */
117         if (op->op_mapped) {
118                 ib_dma_unmap_sg(ic->i_cm_id->device, op->op_sg, 1,
119                                 DMA_FROM_DEVICE);
120                 op->op_mapped = 0;
121         }
122 
123         rds_ib_send_complete(container_of(op, struct rds_message, atomic),
124                              wc_status, rds_atomic_send_complete);
125 
126         if (op->op_type == RDS_ATOMIC_TYPE_CSWP)
127                 rds_ib_stats_inc(s_ib_atomic_cswp);
128         else
129                 rds_ib_stats_inc(s_ib_atomic_fadd);
130 }
131 
132 static void rds_ib_send_unmap_data(struct rds_ib_connection *ic,
133                                    struct rm_data_op *op,
134                                    int wc_status)
135 {
136         struct rds_message *rm = container_of(op, struct rds_message, data);
137 
138         if (op->op_nents)
139                 ib_dma_unmap_sg(ic->i_cm_id->device,
140                                 op->op_sg, op->op_nents,
141                                 DMA_TO_DEVICE);
142 
143         if (rm->rdma.op_active && rm->data.op_notify)
144                 rds_ib_send_unmap_rdma(ic, &rm->rdma, wc_status);
145 }
146 
147 /*
148  * Unmap the resources associated with a struct send_work.
149  *
150  * Returns the rm for no good reason other than it is unobtainable
151  * other than by switching on wr.opcode, currently, and the caller,
152  * the event handler, needs it.
153  */
154 static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic,
155                                                 struct rds_ib_send_work *send,
156                                                 int wc_status)
157 {
158         struct rds_message *rm = NULL;
159 
160         /* In the error case, wc.opcode sometimes contains garbage */
161         switch (send->s_wr.opcode) {
162         case IB_WR_SEND:
163                 if (send->s_op) {
164                         rm = container_of(send->s_op, struct rds_message, data);
165                         rds_ib_send_unmap_data(ic, send->s_op, wc_status);
166                 }
167                 break;
168         case IB_WR_RDMA_WRITE:
169         case IB_WR_RDMA_READ:
170                 if (send->s_op) {
171                         rm = container_of(send->s_op, struct rds_message, rdma);
172                         rds_ib_send_unmap_rdma(ic, send->s_op, wc_status);
173                 }
174                 break;
175         case IB_WR_ATOMIC_FETCH_AND_ADD:
176         case IB_WR_ATOMIC_CMP_AND_SWP:
177                 if (send->s_op) {
178                         rm = container_of(send->s_op, struct rds_message, atomic);
179                         rds_ib_send_unmap_atomic(ic, send->s_op, wc_status);
180                 }
181                 break;
182         default:
183                 printk_ratelimited(KERN_NOTICE
184                                "RDS/IB: %s: unexpected opcode 0x%x in WR!\n",
185                                __func__, send->s_wr.opcode);
186                 break;
187         }
188 
189         send->s_wr.opcode = 0xdead;
190 
191         return rm;
192 }
193 
194 void rds_ib_send_init_ring(struct rds_ib_connection *ic)
195 {
196         struct rds_ib_send_work *send;
197         u32 i;
198 
199         for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
200                 struct ib_sge *sge;
201 
202                 send->s_op = NULL;
203 
204                 send->s_wr.wr_id = i;
205                 send->s_wr.sg_list = send->s_sge;
206                 send->s_wr.ex.imm_data = 0;
207 
208                 sge = &send->s_sge[0];
209                 sge->addr = ic->i_send_hdrs_dma + (i * sizeof(struct rds_header));
210                 sge->length = sizeof(struct rds_header);
211                 sge->lkey = ic->i_pd->local_dma_lkey;
212 
213                 send->s_sge[1].lkey = ic->i_pd->local_dma_lkey;
214         }
215 }
216 
217 void rds_ib_send_clear_ring(struct rds_ib_connection *ic)
218 {
219         struct rds_ib_send_work *send;
220         u32 i;
221 
222         for (i = 0, send = ic->i_sends; i < ic->i_send_ring.w_nr; i++, send++) {
223                 if (send->s_op && send->s_wr.opcode != 0xdead)
224                         rds_ib_send_unmap_op(ic, send, IB_WC_WR_FLUSH_ERR);
225         }
226 }
227 
228 /*
229  * The only fast path caller always has a non-zero nr, so we don't
230  * bother testing nr before performing the atomic sub.
231  */
232 static void rds_ib_sub_signaled(struct rds_ib_connection *ic, int nr)
233 {
234         if ((atomic_sub_return(nr, &ic->i_signaled_sends) == 0) &&
235             waitqueue_active(&rds_ib_ring_empty_wait))
236                 wake_up(&rds_ib_ring_empty_wait);
237         BUG_ON(atomic_read(&ic->i_signaled_sends) < 0);
238 }
239 
240 /*
241  * The _oldest/_free ring operations here race cleanly with the alloc/unalloc
242  * operations performed in the send path.  As the sender allocs and potentially
243  * unallocs the next free entry in the ring it doesn't alter which is
244  * the next to be freed, which is what this is concerned with.
245  */
246 void rds_ib_send_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc)
247 {
248         struct rds_message *rm = NULL;
249         struct rds_connection *conn = ic->conn;
250         struct rds_ib_send_work *send;
251         u32 completed;
252         u32 oldest;
253         u32 i = 0;
254         int nr_sig = 0;
255 
256 
257         rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
258                  (unsigned long long)wc->wr_id, wc->status,
259                  ib_wc_status_msg(wc->status), wc->byte_len,
260                  be32_to_cpu(wc->ex.imm_data));
261         rds_ib_stats_inc(s_ib_tx_cq_event);
262 
263         if (wc->wr_id == RDS_IB_ACK_WR_ID) {
264                 if (time_after(jiffies, ic->i_ack_queued + HZ / 2))
265                         rds_ib_stats_inc(s_ib_tx_stalled);
266                 rds_ib_ack_send_complete(ic);
267                 return;
268         }
269 
270         oldest = rds_ib_ring_oldest(&ic->i_send_ring);
271 
272         completed = rds_ib_ring_completed(&ic->i_send_ring, wc->wr_id, oldest);
273 
274         for (i = 0; i < completed; i++) {
275                 send = &ic->i_sends[oldest];
276                 if (send->s_wr.send_flags & IB_SEND_SIGNALED)
277                         nr_sig++;
278 
279                 rm = rds_ib_send_unmap_op(ic, send, wc->status);
280 
281                 if (time_after(jiffies, send->s_queued + HZ / 2))
282                         rds_ib_stats_inc(s_ib_tx_stalled);
283 
284                 if (send->s_op) {
285                         if (send->s_op == rm->m_final_op) {
286                                 /* If anyone waited for this message to get
287                                  * flushed out, wake them up now
288                                  */
289                                 rds_message_unmapped(rm);
290                         }
291                         rds_message_put(rm);
292                         send->s_op = NULL;
293                 }
294 
295                 oldest = (oldest + 1) % ic->i_send_ring.w_nr;
296         }
297 
298         rds_ib_ring_free(&ic->i_send_ring, completed);
299         rds_ib_sub_signaled(ic, nr_sig);
300         nr_sig = 0;
301 
302         if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags) ||
303             test_bit(0, &conn->c_map_queued))
304                 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
305 
306         /* We expect errors as the qp is drained during shutdown */
307         if (wc->status != IB_WC_SUCCESS && rds_conn_up(conn)) {
308                 rds_ib_conn_error(conn, "send completion on <%pI4,%pI4> had status %u (%s), disconnecting and reconnecting\n",
309                                   &conn->c_laddr, &conn->c_faddr, wc->status,
310                                   ib_wc_status_msg(wc->status));
311         }
312 }
313 
314 /*
315  * This is the main function for allocating credits when sending
316  * messages.
317  *
318  * Conceptually, we have two counters:
319  *  -   send credits: this tells us how many WRs we're allowed
320  *      to submit without overruning the receiver's queue. For
321  *      each SEND WR we post, we decrement this by one.
322  *
323  *  -   posted credits: this tells us how many WRs we recently
324  *      posted to the receive queue. This value is transferred
325  *      to the peer as a "credit update" in a RDS header field.
326  *      Every time we transmit credits to the peer, we subtract
327  *      the amount of transferred credits from this counter.
328  *
329  * It is essential that we avoid situations where both sides have
330  * exhausted their send credits, and are unable to send new credits
331  * to the peer. We achieve this by requiring that we send at least
332  * one credit update to the peer before exhausting our credits.
333  * When new credits arrive, we subtract one credit that is withheld
334  * until we've posted new buffers and are ready to transmit these
335  * credits (see rds_ib_send_add_credits below).
336  *
337  * The RDS send code is essentially single-threaded; rds_send_xmit
338  * sets RDS_IN_XMIT to ensure exclusive access to the send ring.
339  * However, the ACK sending code is independent and can race with
340  * message SENDs.
341  *
342  * In the send path, we need to update the counters for send credits
343  * and the counter of posted buffers atomically - when we use the
344  * last available credit, we cannot allow another thread to race us
345  * and grab the posted credits counter.  Hence, we have to use a
346  * spinlock to protect the credit counter, or use atomics.
347  *
348  * Spinlocks shared between the send and the receive path are bad,
349  * because they create unnecessary delays. An early implementation
350  * using a spinlock showed a 5% degradation in throughput at some
351  * loads.
352  *
353  * This implementation avoids spinlocks completely, putting both
354  * counters into a single atomic, and updating that atomic using
355  * atomic_add (in the receive path, when receiving fresh credits),
356  * and using atomic_cmpxchg when updating the two counters.
357  */
358 int rds_ib_send_grab_credits(struct rds_ib_connection *ic,
359                              u32 wanted, u32 *adv_credits, int need_posted, int max_posted)
360 {
361         unsigned int avail, posted, got = 0, advertise;
362         long oldval, newval;
363 
364         *adv_credits = 0;
365         if (!ic->i_flowctl)
366                 return wanted;
367 
368 try_again:
369         advertise = 0;
370         oldval = newval = atomic_read(&ic->i_credits);
371         posted = IB_GET_POST_CREDITS(oldval);
372         avail = IB_GET_SEND_CREDITS(oldval);
373 
374         rdsdebug("wanted=%u credits=%u posted=%u\n",
375                         wanted, avail, posted);
376 
377         /* The last credit must be used to send a credit update. */
378         if (avail && !posted)
379                 avail--;
380 
381         if (avail < wanted) {
382                 struct rds_connection *conn = ic->i_cm_id->context;
383 
384                 /* Oops, there aren't that many credits left! */
385                 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
386                 got = avail;
387         } else {
388                 /* Sometimes you get what you want, lalala. */
389                 got = wanted;
390         }
391         newval -= IB_SET_SEND_CREDITS(got);
392 
393         /*
394          * If need_posted is non-zero, then the caller wants
395          * the posted regardless of whether any send credits are
396          * available.
397          */
398         if (posted && (got || need_posted)) {
399                 advertise = min_t(unsigned int, posted, max_posted);
400                 newval -= IB_SET_POST_CREDITS(advertise);
401         }
402 
403         /* Finally bill everything */
404         if (atomic_cmpxchg(&ic->i_credits, oldval, newval) != oldval)
405                 goto try_again;
406 
407         *adv_credits = advertise;
408         return got;
409 }
410 
411 void rds_ib_send_add_credits(struct rds_connection *conn, unsigned int credits)
412 {
413         struct rds_ib_connection *ic = conn->c_transport_data;
414 
415         if (credits == 0)
416                 return;
417 
418         rdsdebug("credits=%u current=%u%s\n",
419                         credits,
420                         IB_GET_SEND_CREDITS(atomic_read(&ic->i_credits)),
421                         test_bit(RDS_LL_SEND_FULL, &conn->c_flags) ? ", ll_send_full" : "");
422 
423         atomic_add(IB_SET_SEND_CREDITS(credits), &ic->i_credits);
424         if (test_and_clear_bit(RDS_LL_SEND_FULL, &conn->c_flags))
425                 queue_delayed_work(rds_wq, &conn->c_send_w, 0);
426 
427         WARN_ON(IB_GET_SEND_CREDITS(credits) >= 16384);
428 
429         rds_ib_stats_inc(s_ib_rx_credit_updates);
430 }
431 
432 void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted)
433 {
434         struct rds_ib_connection *ic = conn->c_transport_data;
435 
436         if (posted == 0)
437                 return;
438 
439         atomic_add(IB_SET_POST_CREDITS(posted), &ic->i_credits);
440 
441         /* Decide whether to send an update to the peer now.
442          * If we would send a credit update for every single buffer we
443          * post, we would end up with an ACK storm (ACK arrives,
444          * consumes buffer, we refill the ring, send ACK to remote
445          * advertising the newly posted buffer... ad inf)
446          *
447          * Performance pretty much depends on how often we send
448          * credit updates - too frequent updates mean lots of ACKs.
449          * Too infrequent updates, and the peer will run out of
450          * credits and has to throttle.
451          * For the time being, 16 seems to be a good compromise.
452          */
453         if (IB_GET_POST_CREDITS(atomic_read(&ic->i_credits)) >= 16)
454                 set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
455 }
456 
457 static inline int rds_ib_set_wr_signal_state(struct rds_ib_connection *ic,
458                                              struct rds_ib_send_work *send,
459                                              bool notify)
460 {
461         /*
462          * We want to delay signaling completions just enough to get
463          * the batching benefits but not so much that we create dead time
464          * on the wire.
465          */
466         if (ic->i_unsignaled_wrs-- == 0 || notify) {
467                 ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
468                 send->s_wr.send_flags |= IB_SEND_SIGNALED;
469                 return 1;
470         }
471         return 0;
472 }
473 
474 /*
475  * This can be called multiple times for a given message.  The first time
476  * we see a message we map its scatterlist into the IB device so that
477  * we can provide that mapped address to the IB scatter gather entries
478  * in the IB work requests.  We translate the scatterlist into a series
479  * of work requests that fragment the message.  These work requests complete
480  * in order so we pass ownership of the message to the completion handler
481  * once we send the final fragment.
482  *
483  * The RDS core uses the c_send_lock to only enter this function once
484  * per connection.  This makes sure that the tx ring alloc/unalloc pairs
485  * don't get out of sync and confuse the ring.
486  */
487 int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
488                 unsigned int hdr_off, unsigned int sg, unsigned int off)
489 {
490         struct rds_ib_connection *ic = conn->c_transport_data;
491         struct ib_device *dev = ic->i_cm_id->device;
492         struct rds_ib_send_work *send = NULL;
493         struct rds_ib_send_work *first;
494         struct rds_ib_send_work *prev;
495         struct ib_send_wr *failed_wr;
496         struct scatterlist *scat;
497         u32 pos;
498         u32 i;
499         u32 work_alloc;
500         u32 credit_alloc = 0;
501         u32 posted;
502         u32 adv_credits = 0;
503         int send_flags = 0;
504         int bytes_sent = 0;
505         int ret;
506         int flow_controlled = 0;
507         int nr_sig = 0;
508 
509         BUG_ON(off % RDS_FRAG_SIZE);
510         BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header));
511 
512         /* Do not send cong updates to IB loopback */
513         if (conn->c_loopback
514             && rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) {
515                 rds_cong_map_updated(conn->c_fcong, ~(u64) 0);
516                 scat = &rm->data.op_sg[sg];
517                 ret = max_t(int, RDS_CONG_MAP_BYTES, scat->length);
518                 return sizeof(struct rds_header) + ret;
519         }
520 
521         /* FIXME we may overallocate here */
522         if (be32_to_cpu(rm->m_inc.i_hdr.h_len) == 0)
523                 i = 1;
524         else
525                 i = ceil(be32_to_cpu(rm->m_inc.i_hdr.h_len), RDS_FRAG_SIZE);
526 
527         work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
528         if (work_alloc == 0) {
529                 set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
530                 rds_ib_stats_inc(s_ib_tx_ring_full);
531                 ret = -ENOMEM;
532                 goto out;
533         }
534 
535         if (ic->i_flowctl) {
536                 credit_alloc = rds_ib_send_grab_credits(ic, work_alloc, &posted, 0, RDS_MAX_ADV_CREDIT);
537                 adv_credits += posted;
538                 if (credit_alloc < work_alloc) {
539                         rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - credit_alloc);
540                         work_alloc = credit_alloc;
541                         flow_controlled = 1;
542                 }
543                 if (work_alloc == 0) {
544                         set_bit(RDS_LL_SEND_FULL, &conn->c_flags);
545                         rds_ib_stats_inc(s_ib_tx_throttle);
546                         ret = -ENOMEM;
547                         goto out;
548                 }
549         }
550 
551         /* map the message the first time we see it */
552         if (!ic->i_data_op) {
553                 if (rm->data.op_nents) {
554                         rm->data.op_count = ib_dma_map_sg(dev,
555                                                           rm->data.op_sg,
556                                                           rm->data.op_nents,
557                                                           DMA_TO_DEVICE);
558                         rdsdebug("ic %p mapping rm %p: %d\n", ic, rm, rm->data.op_count);
559                         if (rm->data.op_count == 0) {
560                                 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
561                                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
562                                 ret = -ENOMEM; /* XXX ? */
563                                 goto out;
564                         }
565                 } else {
566                         rm->data.op_count = 0;
567                 }
568 
569                 rds_message_addref(rm);
570                 rm->data.op_dmasg = 0;
571                 rm->data.op_dmaoff = 0;
572                 ic->i_data_op = &rm->data;
573 
574                 /* Finalize the header */
575                 if (test_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags))
576                         rm->m_inc.i_hdr.h_flags |= RDS_FLAG_ACK_REQUIRED;
577                 if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
578                         rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;
579 
580                 /* If it has a RDMA op, tell the peer we did it. This is
581                  * used by the peer to release use-once RDMA MRs. */
582                 if (rm->rdma.op_active) {
583                         struct rds_ext_header_rdma ext_hdr;
584 
585                         ext_hdr.h_rdma_rkey = cpu_to_be32(rm->rdma.op_rkey);
586                         rds_message_add_extension(&rm->m_inc.i_hdr,
587                                         RDS_EXTHDR_RDMA, &ext_hdr, sizeof(ext_hdr));
588                 }
589                 if (rm->m_rdma_cookie) {
590                         rds_message_add_rdma_dest_extension(&rm->m_inc.i_hdr,
591                                         rds_rdma_cookie_key(rm->m_rdma_cookie),
592                                         rds_rdma_cookie_offset(rm->m_rdma_cookie));
593                 }
594 
595                 /* Note - rds_ib_piggyb_ack clears the ACK_REQUIRED bit, so
596                  * we should not do this unless we have a chance of at least
597                  * sticking the header into the send ring. Which is why we
598                  * should call rds_ib_ring_alloc first. */
599                 rm->m_inc.i_hdr.h_ack = cpu_to_be64(rds_ib_piggyb_ack(ic));
600                 rds_message_make_checksum(&rm->m_inc.i_hdr);
601 
602                 /*
603                  * Update adv_credits since we reset the ACK_REQUIRED bit.
604                  */
605                 if (ic->i_flowctl) {
606                         rds_ib_send_grab_credits(ic, 0, &posted, 1, RDS_MAX_ADV_CREDIT - adv_credits);
607                         adv_credits += posted;
608                         BUG_ON(adv_credits > 255);
609                 }
610         }
611 
612         /* Sometimes you want to put a fence between an RDMA
613          * READ and the following SEND.
614          * We could either do this all the time
615          * or when requested by the user. Right now, we let
616          * the application choose.
617          */
618         if (rm->rdma.op_active && rm->rdma.op_fence)
619                 send_flags = IB_SEND_FENCE;
620 
621         /* Each frag gets a header. Msgs may be 0 bytes */
622         send = &ic->i_sends[pos];
623         first = send;
624         prev = NULL;
625         scat = &ic->i_data_op->op_sg[rm->data.op_dmasg];
626         i = 0;
627         do {
628                 unsigned int len = 0;
629 
630                 /* Set up the header */
631                 send->s_wr.send_flags = send_flags;
632                 send->s_wr.opcode = IB_WR_SEND;
633                 send->s_wr.num_sge = 1;
634                 send->s_wr.next = NULL;
635                 send->s_queued = jiffies;
636                 send->s_op = NULL;
637 
638                 send->s_sge[0].addr = ic->i_send_hdrs_dma
639                         + (pos * sizeof(struct rds_header));
640                 send->s_sge[0].length = sizeof(struct rds_header);
641 
642                 memcpy(&ic->i_send_hdrs[pos], &rm->m_inc.i_hdr, sizeof(struct rds_header));
643 
644                 /* Set up the data, if present */
645                 if (i < work_alloc
646                     && scat != &rm->data.op_sg[rm->data.op_count]) {
647                         len = min(RDS_FRAG_SIZE,
648                                 ib_sg_dma_len(dev, scat) - rm->data.op_dmaoff);
649                         send->s_wr.num_sge = 2;
650 
651                         send->s_sge[1].addr = ib_sg_dma_address(dev, scat);
652                         send->s_sge[1].addr += rm->data.op_dmaoff;
653                         send->s_sge[1].length = len;
654 
655                         bytes_sent += len;
656                         rm->data.op_dmaoff += len;
657                         if (rm->data.op_dmaoff == ib_sg_dma_len(dev, scat)) {
658                                 scat++;
659                                 rm->data.op_dmasg++;
660                                 rm->data.op_dmaoff = 0;
661                         }
662                 }
663 
664                 rds_ib_set_wr_signal_state(ic, send, false);
665 
666                 /*
667                  * Always signal the last one if we're stopping due to flow control.
668                  */
669                 if (ic->i_flowctl && flow_controlled && i == (work_alloc - 1)) {
670                         rds_ib_set_wr_signal_state(ic, send, true);
671                         send->s_wr.send_flags |= IB_SEND_SOLICITED;
672                 }
673 
674                 if (send->s_wr.send_flags & IB_SEND_SIGNALED)
675                         nr_sig++;
676 
677                 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
678                          &send->s_wr, send->s_wr.num_sge, send->s_wr.next);
679 
680                 if (ic->i_flowctl && adv_credits) {
681                         struct rds_header *hdr = &ic->i_send_hdrs[pos];
682 
683                         /* add credit and redo the header checksum */
684                         hdr->h_credit = adv_credits;
685                         rds_message_make_checksum(hdr);
686                         adv_credits = 0;
687                         rds_ib_stats_inc(s_ib_tx_credit_updates);
688                 }
689 
690                 if (prev)
691                         prev->s_wr.next = &send->s_wr;
692                 prev = send;
693 
694                 pos = (pos + 1) % ic->i_send_ring.w_nr;
695                 send = &ic->i_sends[pos];
696                 i++;
697 
698         } while (i < work_alloc
699                  && scat != &rm->data.op_sg[rm->data.op_count]);
700 
701         /* Account the RDS header in the number of bytes we sent, but just once.
702          * The caller has no concept of fragmentation. */
703         if (hdr_off == 0)
704                 bytes_sent += sizeof(struct rds_header);
705 
706         /* if we finished the message then send completion owns it */
707         if (scat == &rm->data.op_sg[rm->data.op_count]) {
708                 prev->s_op = ic->i_data_op;
709                 prev->s_wr.send_flags |= IB_SEND_SOLICITED;
710                 if (!(prev->s_wr.send_flags & IB_SEND_SIGNALED))
711                         nr_sig += rds_ib_set_wr_signal_state(ic, prev, true);
712                 ic->i_data_op = NULL;
713         }
714 
715         /* Put back wrs & credits we didn't use */
716         if (i < work_alloc) {
717                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
718                 work_alloc = i;
719         }
720         if (ic->i_flowctl && i < credit_alloc)
721                 rds_ib_send_add_credits(conn, credit_alloc - i);
722 
723         if (nr_sig)
724                 atomic_add(nr_sig, &ic->i_signaled_sends);
725 
726         /* XXX need to worry about failed_wr and partial sends. */
727         failed_wr = &first->s_wr;
728         ret = ib_post_send(ic->i_cm_id->qp, &first->s_wr, &failed_wr);
729         rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
730                  first, &first->s_wr, ret, failed_wr);
731         BUG_ON(failed_wr != &first->s_wr);
732         if (ret) {
733                 printk(KERN_WARNING "RDS/IB: ib_post_send to %pI4 "
734                        "returned %d\n", &conn->c_faddr, ret);
735                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
736                 rds_ib_sub_signaled(ic, nr_sig);
737                 if (prev->s_op) {
738                         ic->i_data_op = prev->s_op;
739                         prev->s_op = NULL;
740                 }
741 
742                 rds_ib_conn_error(ic->conn, "ib_post_send failed\n");
743                 goto out;
744         }
745 
746         ret = bytes_sent;
747 out:
748         BUG_ON(adv_credits);
749         return ret;
750 }
751 
752 /*
753  * Issue atomic operation.
754  * A simplified version of the rdma case, we always map 1 SG, and
755  * only 8 bytes, for the return value from the atomic operation.
756  */
757 int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op)
758 {
759         struct rds_ib_connection *ic = conn->c_transport_data;
760         struct rds_ib_send_work *send = NULL;
761         struct ib_send_wr *failed_wr;
762         struct rds_ib_device *rds_ibdev;
763         u32 pos;
764         u32 work_alloc;
765         int ret;
766         int nr_sig = 0;
767 
768         rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client);
769 
770         work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, 1, &pos);
771         if (work_alloc != 1) {
772                 rds_ib_stats_inc(s_ib_tx_ring_full);
773                 ret = -ENOMEM;
774                 goto out;
775         }
776 
777         /* address of send request in ring */
778         send = &ic->i_sends[pos];
779         send->s_queued = jiffies;
780 
781         if (op->op_type == RDS_ATOMIC_TYPE_CSWP) {
782                 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_CMP_AND_SWP;
783                 send->s_atomic_wr.compare_add = op->op_m_cswp.compare;
784                 send->s_atomic_wr.swap = op->op_m_cswp.swap;
785                 send->s_atomic_wr.compare_add_mask = op->op_m_cswp.compare_mask;
786                 send->s_atomic_wr.swap_mask = op->op_m_cswp.swap_mask;
787         } else { /* FADD */
788                 send->s_atomic_wr.wr.opcode = IB_WR_MASKED_ATOMIC_FETCH_AND_ADD;
789                 send->s_atomic_wr.compare_add = op->op_m_fadd.add;
790                 send->s_atomic_wr.swap = 0;
791                 send->s_atomic_wr.compare_add_mask = op->op_m_fadd.nocarry_mask;
792                 send->s_atomic_wr.swap_mask = 0;
793         }
794         send->s_wr.send_flags = 0;
795         nr_sig = rds_ib_set_wr_signal_state(ic, send, op->op_notify);
796         send->s_atomic_wr.wr.num_sge = 1;
797         send->s_atomic_wr.wr.next = NULL;
798         send->s_atomic_wr.remote_addr = op->op_remote_addr;
799         send->s_atomic_wr.rkey = op->op_rkey;
800         send->s_op = op;
801         rds_message_addref(container_of(send->s_op, struct rds_message, atomic));
802 
803         /* map 8 byte retval buffer to the device */
804         ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE);
805         rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret);
806         if (ret != 1) {
807                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
808                 rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
809                 ret = -ENOMEM; /* XXX ? */
810                 goto out;
811         }
812 
813         /* Convert our struct scatterlist to struct ib_sge */
814         send->s_sge[0].addr = ib_sg_dma_address(ic->i_cm_id->device, op->op_sg);
815         send->s_sge[0].length = ib_sg_dma_len(ic->i_cm_id->device, op->op_sg);
816         send->s_sge[0].lkey = ic->i_pd->local_dma_lkey;
817 
818         rdsdebug("rva %Lx rpa %Lx len %u\n", op->op_remote_addr,
819                  send->s_sge[0].addr, send->s_sge[0].length);
820 
821         if (nr_sig)
822                 atomic_add(nr_sig, &ic->i_signaled_sends);
823 
824         failed_wr = &send->s_atomic_wr.wr;
825         ret = ib_post_send(ic->i_cm_id->qp, &send->s_atomic_wr.wr, &failed_wr);
826         rdsdebug("ic %p send %p (wr %p) ret %d wr %p\n", ic,
827                  send, &send->s_atomic_wr, ret, failed_wr);
828         BUG_ON(failed_wr != &send->s_atomic_wr.wr);
829         if (ret) {
830                 printk(KERN_WARNING "RDS/IB: atomic ib_post_send to %pI4 "
831                        "returned %d\n", &conn->c_faddr, ret);
832                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
833                 rds_ib_sub_signaled(ic, nr_sig);
834                 goto out;
835         }
836 
837         if (unlikely(failed_wr != &send->s_atomic_wr.wr)) {
838                 printk(KERN_WARNING "RDS/IB: atomic ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
839                 BUG_ON(failed_wr != &send->s_atomic_wr.wr);
840         }
841 
842 out:
843         return ret;
844 }
845 
846 int rds_ib_xmit_rdma(struct rds_connection *conn, struct rm_rdma_op *op)
847 {
848         struct rds_ib_connection *ic = conn->c_transport_data;
849         struct rds_ib_send_work *send = NULL;
850         struct rds_ib_send_work *first;
851         struct rds_ib_send_work *prev;
852         struct ib_send_wr *failed_wr;
853         struct scatterlist *scat;
854         unsigned long len;
855         u64 remote_addr = op->op_remote_addr;
856         u32 max_sge = ic->rds_ibdev->max_sge;
857         u32 pos;
858         u32 work_alloc;
859         u32 i;
860         u32 j;
861         int sent;
862         int ret;
863         int num_sge;
864         int nr_sig = 0;
865 
866         /* map the op the first time we see it */
867         if (!op->op_mapped) {
868                 op->op_count = ib_dma_map_sg(ic->i_cm_id->device,
869                                              op->op_sg, op->op_nents, (op->op_write) ?
870                                              DMA_TO_DEVICE : DMA_FROM_DEVICE);
871                 rdsdebug("ic %p mapping op %p: %d\n", ic, op, op->op_count);
872                 if (op->op_count == 0) {
873                         rds_ib_stats_inc(s_ib_tx_sg_mapping_failure);
874                         ret = -ENOMEM; /* XXX ? */
875                         goto out;
876                 }
877 
878                 op->op_mapped = 1;
879         }
880 
881         /*
882          * Instead of knowing how to return a partial rdma read/write we insist that there
883          * be enough work requests to send the entire message.
884          */
885         i = ceil(op->op_count, max_sge);
886 
887         work_alloc = rds_ib_ring_alloc(&ic->i_send_ring, i, &pos);
888         if (work_alloc != i) {
889                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
890                 rds_ib_stats_inc(s_ib_tx_ring_full);
891                 ret = -ENOMEM;
892                 goto out;
893         }
894 
895         send = &ic->i_sends[pos];
896         first = send;
897         prev = NULL;
898         scat = &op->op_sg[0];
899         sent = 0;
900         num_sge = op->op_count;
901 
902         for (i = 0; i < work_alloc && scat != &op->op_sg[op->op_count]; i++) {
903                 send->s_wr.send_flags = 0;
904                 send->s_queued = jiffies;
905                 send->s_op = NULL;
906 
907                 nr_sig += rds_ib_set_wr_signal_state(ic, send, op->op_notify);
908 
909                 send->s_wr.opcode = op->op_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ;
910                 send->s_rdma_wr.remote_addr = remote_addr;
911                 send->s_rdma_wr.rkey = op->op_rkey;
912 
913                 if (num_sge > max_sge) {
914                         send->s_rdma_wr.wr.num_sge = max_sge;
915                         num_sge -= max_sge;
916                 } else {
917                         send->s_rdma_wr.wr.num_sge = num_sge;
918                 }
919 
920                 send->s_rdma_wr.wr.next = NULL;
921 
922                 if (prev)
923                         prev->s_rdma_wr.wr.next = &send->s_rdma_wr.wr;
924 
925                 for (j = 0; j < send->s_rdma_wr.wr.num_sge &&
926                      scat != &op->op_sg[op->op_count]; j++) {
927                         len = ib_sg_dma_len(ic->i_cm_id->device, scat);
928                         send->s_sge[j].addr =
929                                  ib_sg_dma_address(ic->i_cm_id->device, scat);
930                         send->s_sge[j].length = len;
931                         send->s_sge[j].lkey = ic->i_pd->local_dma_lkey;
932 
933                         sent += len;
934                         rdsdebug("ic %p sent %d remote_addr %llu\n", ic, sent, remote_addr);
935 
936                         remote_addr += len;
937                         scat++;
938                 }
939 
940                 rdsdebug("send %p wr %p num_sge %u next %p\n", send,
941                         &send->s_rdma_wr.wr,
942                         send->s_rdma_wr.wr.num_sge,
943                         send->s_rdma_wr.wr.next);
944 
945                 prev = send;
946                 if (++send == &ic->i_sends[ic->i_send_ring.w_nr])
947                         send = ic->i_sends;
948         }
949 
950         /* give a reference to the last op */
951         if (scat == &op->op_sg[op->op_count]) {
952                 prev->s_op = op;
953                 rds_message_addref(container_of(op, struct rds_message, rdma));
954         }
955 
956         if (i < work_alloc) {
957                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
958                 work_alloc = i;
959         }
960 
961         if (nr_sig)
962                 atomic_add(nr_sig, &ic->i_signaled_sends);
963 
964         failed_wr = &first->s_rdma_wr.wr;
965         ret = ib_post_send(ic->i_cm_id->qp, &first->s_rdma_wr.wr, &failed_wr);
966         rdsdebug("ic %p first %p (wr %p) ret %d wr %p\n", ic,
967                  first, &first->s_rdma_wr.wr, ret, failed_wr);
968         BUG_ON(failed_wr != &first->s_rdma_wr.wr);
969         if (ret) {
970                 printk(KERN_WARNING "RDS/IB: rdma ib_post_send to %pI4 "
971                        "returned %d\n", &conn->c_faddr, ret);
972                 rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc);
973                 rds_ib_sub_signaled(ic, nr_sig);
974                 goto out;
975         }
976 
977         if (unlikely(failed_wr != &first->s_rdma_wr.wr)) {
978                 printk(KERN_WARNING "RDS/IB: ib_post_send() rc=%d, but failed_wqe updated!\n", ret);
979                 BUG_ON(failed_wr != &first->s_rdma_wr.wr);
980         }
981 
982 
983 out:
984         return ret;
985 }
986 
987 void rds_ib_xmit_path_complete(struct rds_conn_path *cp)
988 {
989         struct rds_connection *conn = cp->cp_conn;
990         struct rds_ib_connection *ic = conn->c_transport_data;
991 
992         /* We may have a pending ACK or window update we were unable
993          * to send previously (due to flow control). Try again. */
994         rds_ib_attempt_ack(ic);
995 }
996 

~ [ 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