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1093 lines
31 KiB
1093 lines
31 KiB
/* |
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* Copyright (c) 2006, 2019 Oracle and/or its affiliates. All rights reserved. |
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* |
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* This software is available to you under a choice of one of two |
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* licenses. You may choose to be licensed under the terms of the GNU |
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* General Public License (GPL) Version 2, available from the file |
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* COPYING in the main directory of this source tree, or the |
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* OpenIB.org BSD license below: |
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* |
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* Redistribution and use in source and binary forms, with or |
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* without modification, are permitted provided that the following |
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* conditions are met: |
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* |
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* - Redistributions of source code must retain the above |
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* copyright notice, this list of conditions and the following |
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* disclaimer. |
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* |
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* - Redistributions in binary form must reproduce the above |
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* copyright notice, this list of conditions and the following |
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* disclaimer in the documentation and/or other materials |
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* provided with the distribution. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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* SOFTWARE. |
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* |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/pci.h> |
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#include <linux/dma-mapping.h> |
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#include <rdma/rdma_cm.h> |
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|
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#include "rds_single_path.h" |
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#include "rds.h" |
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#include "ib.h" |
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|
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static struct kmem_cache *rds_ib_incoming_slab; |
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static struct kmem_cache *rds_ib_frag_slab; |
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static atomic_t rds_ib_allocation = ATOMIC_INIT(0); |
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|
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void rds_ib_recv_init_ring(struct rds_ib_connection *ic) |
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{ |
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struct rds_ib_recv_work *recv; |
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u32 i; |
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|
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for (i = 0, recv = ic->i_recvs; i < ic->i_recv_ring.w_nr; i++, recv++) { |
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struct ib_sge *sge; |
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|
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recv->r_ibinc = NULL; |
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recv->r_frag = NULL; |
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|
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recv->r_wr.next = NULL; |
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recv->r_wr.wr_id = i; |
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recv->r_wr.sg_list = recv->r_sge; |
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recv->r_wr.num_sge = RDS_IB_RECV_SGE; |
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|
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sge = &recv->r_sge[0]; |
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sge->addr = ic->i_recv_hdrs_dma[i]; |
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sge->length = sizeof(struct rds_header); |
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sge->lkey = ic->i_pd->local_dma_lkey; |
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|
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sge = &recv->r_sge[1]; |
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sge->addr = 0; |
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sge->length = RDS_FRAG_SIZE; |
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sge->lkey = ic->i_pd->local_dma_lkey; |
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} |
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} |
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|
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/* |
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* The entire 'from' list, including the from element itself, is put on |
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* to the tail of the 'to' list. |
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*/ |
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static void list_splice_entire_tail(struct list_head *from, |
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struct list_head *to) |
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{ |
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struct list_head *from_last = from->prev; |
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|
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list_splice_tail(from_last, to); |
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list_add_tail(from_last, to); |
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} |
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|
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static void rds_ib_cache_xfer_to_ready(struct rds_ib_refill_cache *cache) |
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{ |
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struct list_head *tmp; |
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|
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tmp = xchg(&cache->xfer, NULL); |
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if (tmp) { |
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if (cache->ready) |
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list_splice_entire_tail(tmp, cache->ready); |
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else |
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cache->ready = tmp; |
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} |
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} |
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|
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static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache, gfp_t gfp) |
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{ |
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struct rds_ib_cache_head *head; |
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int cpu; |
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|
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cache->percpu = alloc_percpu_gfp(struct rds_ib_cache_head, gfp); |
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if (!cache->percpu) |
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return -ENOMEM; |
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|
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for_each_possible_cpu(cpu) { |
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head = per_cpu_ptr(cache->percpu, cpu); |
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head->first = NULL; |
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head->count = 0; |
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} |
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cache->xfer = NULL; |
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cache->ready = NULL; |
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|
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return 0; |
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} |
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|
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int rds_ib_recv_alloc_caches(struct rds_ib_connection *ic, gfp_t gfp) |
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{ |
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int ret; |
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|
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ret = rds_ib_recv_alloc_cache(&ic->i_cache_incs, gfp); |
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if (!ret) { |
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ret = rds_ib_recv_alloc_cache(&ic->i_cache_frags, gfp); |
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if (ret) |
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free_percpu(ic->i_cache_incs.percpu); |
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} |
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return ret; |
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} |
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|
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static void rds_ib_cache_splice_all_lists(struct rds_ib_refill_cache *cache, |
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struct list_head *caller_list) |
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{ |
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struct rds_ib_cache_head *head; |
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int cpu; |
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|
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for_each_possible_cpu(cpu) { |
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head = per_cpu_ptr(cache->percpu, cpu); |
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if (head->first) { |
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list_splice_entire_tail(head->first, caller_list); |
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head->first = NULL; |
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} |
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} |
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|
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if (cache->ready) { |
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list_splice_entire_tail(cache->ready, caller_list); |
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cache->ready = NULL; |
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} |
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} |
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|
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void rds_ib_recv_free_caches(struct rds_ib_connection *ic) |
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{ |
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struct rds_ib_incoming *inc; |
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struct rds_ib_incoming *inc_tmp; |
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struct rds_page_frag *frag; |
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struct rds_page_frag *frag_tmp; |
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LIST_HEAD(list); |
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|
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rds_ib_cache_xfer_to_ready(&ic->i_cache_incs); |
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rds_ib_cache_splice_all_lists(&ic->i_cache_incs, &list); |
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free_percpu(ic->i_cache_incs.percpu); |
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|
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list_for_each_entry_safe(inc, inc_tmp, &list, ii_cache_entry) { |
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list_del(&inc->ii_cache_entry); |
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WARN_ON(!list_empty(&inc->ii_frags)); |
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kmem_cache_free(rds_ib_incoming_slab, inc); |
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atomic_dec(&rds_ib_allocation); |
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} |
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rds_ib_cache_xfer_to_ready(&ic->i_cache_frags); |
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rds_ib_cache_splice_all_lists(&ic->i_cache_frags, &list); |
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free_percpu(ic->i_cache_frags.percpu); |
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|
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list_for_each_entry_safe(frag, frag_tmp, &list, f_cache_entry) { |
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list_del(&frag->f_cache_entry); |
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WARN_ON(!list_empty(&frag->f_item)); |
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kmem_cache_free(rds_ib_frag_slab, frag); |
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} |
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} |
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|
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/* fwd decl */ |
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static void rds_ib_recv_cache_put(struct list_head *new_item, |
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struct rds_ib_refill_cache *cache); |
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static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache); |
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|
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|
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/* Recycle frag and attached recv buffer f_sg */ |
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static void rds_ib_frag_free(struct rds_ib_connection *ic, |
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struct rds_page_frag *frag) |
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{ |
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rdsdebug("frag %p page %p\n", frag, sg_page(&frag->f_sg)); |
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|
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rds_ib_recv_cache_put(&frag->f_cache_entry, &ic->i_cache_frags); |
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atomic_add(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs); |
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rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE); |
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} |
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|
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/* Recycle inc after freeing attached frags */ |
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void rds_ib_inc_free(struct rds_incoming *inc) |
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{ |
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struct rds_ib_incoming *ibinc; |
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struct rds_page_frag *frag; |
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struct rds_page_frag *pos; |
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struct rds_ib_connection *ic = inc->i_conn->c_transport_data; |
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|
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ibinc = container_of(inc, struct rds_ib_incoming, ii_inc); |
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|
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/* Free attached frags */ |
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list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) { |
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list_del_init(&frag->f_item); |
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rds_ib_frag_free(ic, frag); |
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} |
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BUG_ON(!list_empty(&ibinc->ii_frags)); |
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|
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rdsdebug("freeing ibinc %p inc %p\n", ibinc, inc); |
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rds_ib_recv_cache_put(&ibinc->ii_cache_entry, &ic->i_cache_incs); |
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} |
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|
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static void rds_ib_recv_clear_one(struct rds_ib_connection *ic, |
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struct rds_ib_recv_work *recv) |
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{ |
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if (recv->r_ibinc) { |
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rds_inc_put(&recv->r_ibinc->ii_inc); |
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recv->r_ibinc = NULL; |
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} |
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if (recv->r_frag) { |
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ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE); |
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rds_ib_frag_free(ic, recv->r_frag); |
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recv->r_frag = NULL; |
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} |
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} |
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void rds_ib_recv_clear_ring(struct rds_ib_connection *ic) |
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{ |
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u32 i; |
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for (i = 0; i < ic->i_recv_ring.w_nr; i++) |
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rds_ib_recv_clear_one(ic, &ic->i_recvs[i]); |
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} |
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static struct rds_ib_incoming *rds_ib_refill_one_inc(struct rds_ib_connection *ic, |
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gfp_t slab_mask) |
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{ |
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struct rds_ib_incoming *ibinc; |
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struct list_head *cache_item; |
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int avail_allocs; |
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|
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cache_item = rds_ib_recv_cache_get(&ic->i_cache_incs); |
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if (cache_item) { |
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ibinc = container_of(cache_item, struct rds_ib_incoming, ii_cache_entry); |
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} else { |
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avail_allocs = atomic_add_unless(&rds_ib_allocation, |
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1, rds_ib_sysctl_max_recv_allocation); |
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if (!avail_allocs) { |
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rds_ib_stats_inc(s_ib_rx_alloc_limit); |
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return NULL; |
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} |
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ibinc = kmem_cache_alloc(rds_ib_incoming_slab, slab_mask); |
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if (!ibinc) { |
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atomic_dec(&rds_ib_allocation); |
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return NULL; |
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} |
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rds_ib_stats_inc(s_ib_rx_total_incs); |
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} |
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INIT_LIST_HEAD(&ibinc->ii_frags); |
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rds_inc_init(&ibinc->ii_inc, ic->conn, &ic->conn->c_faddr); |
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|
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return ibinc; |
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} |
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|
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static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic, |
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gfp_t slab_mask, gfp_t page_mask) |
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{ |
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struct rds_page_frag *frag; |
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struct list_head *cache_item; |
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int ret; |
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|
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cache_item = rds_ib_recv_cache_get(&ic->i_cache_frags); |
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if (cache_item) { |
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frag = container_of(cache_item, struct rds_page_frag, f_cache_entry); |
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atomic_sub(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs); |
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rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE); |
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} else { |
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frag = kmem_cache_alloc(rds_ib_frag_slab, slab_mask); |
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if (!frag) |
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return NULL; |
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|
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sg_init_table(&frag->f_sg, 1); |
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ret = rds_page_remainder_alloc(&frag->f_sg, |
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RDS_FRAG_SIZE, page_mask); |
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if (ret) { |
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kmem_cache_free(rds_ib_frag_slab, frag); |
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return NULL; |
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} |
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rds_ib_stats_inc(s_ib_rx_total_frags); |
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} |
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|
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INIT_LIST_HEAD(&frag->f_item); |
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|
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return frag; |
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} |
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|
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static int rds_ib_recv_refill_one(struct rds_connection *conn, |
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struct rds_ib_recv_work *recv, gfp_t gfp) |
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{ |
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struct rds_ib_connection *ic = conn->c_transport_data; |
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struct ib_sge *sge; |
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int ret = -ENOMEM; |
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gfp_t slab_mask = gfp; |
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gfp_t page_mask = gfp; |
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|
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if (gfp & __GFP_DIRECT_RECLAIM) { |
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slab_mask = GFP_KERNEL; |
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page_mask = GFP_HIGHUSER; |
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} |
|
|
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if (!ic->i_cache_incs.ready) |
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rds_ib_cache_xfer_to_ready(&ic->i_cache_incs); |
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if (!ic->i_cache_frags.ready) |
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rds_ib_cache_xfer_to_ready(&ic->i_cache_frags); |
|
|
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/* |
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* ibinc was taken from recv if recv contained the start of a message. |
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* recvs that were continuations will still have this allocated. |
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*/ |
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if (!recv->r_ibinc) { |
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recv->r_ibinc = rds_ib_refill_one_inc(ic, slab_mask); |
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if (!recv->r_ibinc) |
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goto out; |
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} |
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|
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WARN_ON(recv->r_frag); /* leak! */ |
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recv->r_frag = rds_ib_refill_one_frag(ic, slab_mask, page_mask); |
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if (!recv->r_frag) |
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goto out; |
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|
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ret = ib_dma_map_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, |
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1, DMA_FROM_DEVICE); |
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WARN_ON(ret != 1); |
|
|
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sge = &recv->r_sge[0]; |
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sge->addr = ic->i_recv_hdrs_dma[recv - ic->i_recvs]; |
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sge->length = sizeof(struct rds_header); |
|
|
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sge = &recv->r_sge[1]; |
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sge->addr = sg_dma_address(&recv->r_frag->f_sg); |
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sge->length = sg_dma_len(&recv->r_frag->f_sg); |
|
|
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ret = 0; |
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out: |
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return ret; |
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} |
|
|
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static int acquire_refill(struct rds_connection *conn) |
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{ |
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return test_and_set_bit(RDS_RECV_REFILL, &conn->c_flags) == 0; |
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} |
|
|
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static void release_refill(struct rds_connection *conn) |
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{ |
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clear_bit(RDS_RECV_REFILL, &conn->c_flags); |
|
|
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/* We don't use wait_on_bit()/wake_up_bit() because our waking is in a |
|
* hot path and finding waiters is very rare. We don't want to walk |
|
* the system-wide hashed waitqueue buckets in the fast path only to |
|
* almost never find waiters. |
|
*/ |
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if (waitqueue_active(&conn->c_waitq)) |
|
wake_up_all(&conn->c_waitq); |
|
} |
|
|
|
/* |
|
* This tries to allocate and post unused work requests after making sure that |
|
* they have all the allocations they need to queue received fragments into |
|
* sockets. |
|
*/ |
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void rds_ib_recv_refill(struct rds_connection *conn, int prefill, gfp_t gfp) |
|
{ |
|
struct rds_ib_connection *ic = conn->c_transport_data; |
|
struct rds_ib_recv_work *recv; |
|
unsigned int posted = 0; |
|
int ret = 0; |
|
bool can_wait = !!(gfp & __GFP_DIRECT_RECLAIM); |
|
bool must_wake = false; |
|
u32 pos; |
|
|
|
/* the goal here is to just make sure that someone, somewhere |
|
* is posting buffers. If we can't get the refill lock, |
|
* let them do their thing |
|
*/ |
|
if (!acquire_refill(conn)) |
|
return; |
|
|
|
while ((prefill || rds_conn_up(conn)) && |
|
rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) { |
|
if (pos >= ic->i_recv_ring.w_nr) { |
|
printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n", |
|
pos); |
|
break; |
|
} |
|
|
|
recv = &ic->i_recvs[pos]; |
|
ret = rds_ib_recv_refill_one(conn, recv, gfp); |
|
if (ret) { |
|
must_wake = true; |
|
break; |
|
} |
|
|
|
rdsdebug("recv %p ibinc %p page %p addr %lu\n", recv, |
|
recv->r_ibinc, sg_page(&recv->r_frag->f_sg), |
|
(long)sg_dma_address(&recv->r_frag->f_sg)); |
|
|
|
/* XXX when can this fail? */ |
|
ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, NULL); |
|
if (ret) { |
|
rds_ib_conn_error(conn, "recv post on " |
|
"%pI6c returned %d, disconnecting and " |
|
"reconnecting\n", &conn->c_faddr, |
|
ret); |
|
break; |
|
} |
|
|
|
posted++; |
|
|
|
if ((posted > 128 && need_resched()) || posted > 8192) { |
|
must_wake = true; |
|
break; |
|
} |
|
} |
|
|
|
/* We're doing flow control - update the window. */ |
|
if (ic->i_flowctl && posted) |
|
rds_ib_advertise_credits(conn, posted); |
|
|
|
if (ret) |
|
rds_ib_ring_unalloc(&ic->i_recv_ring, 1); |
|
|
|
release_refill(conn); |
|
|
|
/* if we're called from the softirq handler, we'll be GFP_NOWAIT. |
|
* in this case the ring being low is going to lead to more interrupts |
|
* and we can safely let the softirq code take care of it unless the |
|
* ring is completely empty. |
|
* |
|
* if we're called from krdsd, we'll be GFP_KERNEL. In this case |
|
* we might have raced with the softirq code while we had the refill |
|
* lock held. Use rds_ib_ring_low() instead of ring_empty to decide |
|
* if we should requeue. |
|
*/ |
|
if (rds_conn_up(conn) && |
|
(must_wake || |
|
(can_wait && rds_ib_ring_low(&ic->i_recv_ring)) || |
|
rds_ib_ring_empty(&ic->i_recv_ring))) { |
|
queue_delayed_work(rds_wq, &conn->c_recv_w, 1); |
|
} |
|
if (can_wait) |
|
cond_resched(); |
|
} |
|
|
|
/* |
|
* We want to recycle several types of recv allocations, like incs and frags. |
|
* To use this, the *_free() function passes in the ptr to a list_head within |
|
* the recyclee, as well as the cache to put it on. |
|
* |
|
* First, we put the memory on a percpu list. When this reaches a certain size, |
|
* We move it to an intermediate non-percpu list in a lockless manner, with some |
|
* xchg/compxchg wizardry. |
|
* |
|
* N.B. Instead of a list_head as the anchor, we use a single pointer, which can |
|
* be NULL and xchg'd. The list is actually empty when the pointer is NULL, and |
|
* list_empty() will return true with one element is actually present. |
|
*/ |
|
static void rds_ib_recv_cache_put(struct list_head *new_item, |
|
struct rds_ib_refill_cache *cache) |
|
{ |
|
unsigned long flags; |
|
struct list_head *old, *chpfirst; |
|
|
|
local_irq_save(flags); |
|
|
|
chpfirst = __this_cpu_read(cache->percpu->first); |
|
if (!chpfirst) |
|
INIT_LIST_HEAD(new_item); |
|
else /* put on front */ |
|
list_add_tail(new_item, chpfirst); |
|
|
|
__this_cpu_write(cache->percpu->first, new_item); |
|
__this_cpu_inc(cache->percpu->count); |
|
|
|
if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT) |
|
goto end; |
|
|
|
/* |
|
* Return our per-cpu first list to the cache's xfer by atomically |
|
* grabbing the current xfer list, appending it to our per-cpu list, |
|
* and then atomically returning that entire list back to the |
|
* cache's xfer list as long as it's still empty. |
|
*/ |
|
do { |
|
old = xchg(&cache->xfer, NULL); |
|
if (old) |
|
list_splice_entire_tail(old, chpfirst); |
|
old = cmpxchg(&cache->xfer, NULL, chpfirst); |
|
} while (old); |
|
|
|
|
|
__this_cpu_write(cache->percpu->first, NULL); |
|
__this_cpu_write(cache->percpu->count, 0); |
|
end: |
|
local_irq_restore(flags); |
|
} |
|
|
|
static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache) |
|
{ |
|
struct list_head *head = cache->ready; |
|
|
|
if (head) { |
|
if (!list_empty(head)) { |
|
cache->ready = head->next; |
|
list_del_init(head); |
|
} else |
|
cache->ready = NULL; |
|
} |
|
|
|
return head; |
|
} |
|
|
|
int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to) |
|
{ |
|
struct rds_ib_incoming *ibinc; |
|
struct rds_page_frag *frag; |
|
unsigned long to_copy; |
|
unsigned long frag_off = 0; |
|
int copied = 0; |
|
int ret; |
|
u32 len; |
|
|
|
ibinc = container_of(inc, struct rds_ib_incoming, ii_inc); |
|
frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item); |
|
len = be32_to_cpu(inc->i_hdr.h_len); |
|
|
|
while (iov_iter_count(to) && copied < len) { |
|
if (frag_off == RDS_FRAG_SIZE) { |
|
frag = list_entry(frag->f_item.next, |
|
struct rds_page_frag, f_item); |
|
frag_off = 0; |
|
} |
|
to_copy = min_t(unsigned long, iov_iter_count(to), |
|
RDS_FRAG_SIZE - frag_off); |
|
to_copy = min_t(unsigned long, to_copy, len - copied); |
|
|
|
/* XXX needs + offset for multiple recvs per page */ |
|
rds_stats_add(s_copy_to_user, to_copy); |
|
ret = copy_page_to_iter(sg_page(&frag->f_sg), |
|
frag->f_sg.offset + frag_off, |
|
to_copy, |
|
to); |
|
if (ret != to_copy) |
|
return -EFAULT; |
|
|
|
frag_off += to_copy; |
|
copied += to_copy; |
|
} |
|
|
|
return copied; |
|
} |
|
|
|
/* ic starts out kzalloc()ed */ |
|
void rds_ib_recv_init_ack(struct rds_ib_connection *ic) |
|
{ |
|
struct ib_send_wr *wr = &ic->i_ack_wr; |
|
struct ib_sge *sge = &ic->i_ack_sge; |
|
|
|
sge->addr = ic->i_ack_dma; |
|
sge->length = sizeof(struct rds_header); |
|
sge->lkey = ic->i_pd->local_dma_lkey; |
|
|
|
wr->sg_list = sge; |
|
wr->num_sge = 1; |
|
wr->opcode = IB_WR_SEND; |
|
wr->wr_id = RDS_IB_ACK_WR_ID; |
|
wr->send_flags = IB_SEND_SIGNALED | IB_SEND_SOLICITED; |
|
} |
|
|
|
/* |
|
* You'd think that with reliable IB connections you wouldn't need to ack |
|
* messages that have been received. The problem is that IB hardware generates |
|
* an ack message before it has DMAed the message into memory. This creates a |
|
* potential message loss if the HCA is disabled for any reason between when it |
|
* sends the ack and before the message is DMAed and processed. This is only a |
|
* potential issue if another HCA is available for fail-over. |
|
* |
|
* When the remote host receives our ack they'll free the sent message from |
|
* their send queue. To decrease the latency of this we always send an ack |
|
* immediately after we've received messages. |
|
* |
|
* For simplicity, we only have one ack in flight at a time. This puts |
|
* pressure on senders to have deep enough send queues to absorb the latency of |
|
* a single ack frame being in flight. This might not be good enough. |
|
* |
|
* This is implemented by have a long-lived send_wr and sge which point to a |
|
* statically allocated ack frame. This ack wr does not fall under the ring |
|
* accounting that the tx and rx wrs do. The QP attribute specifically makes |
|
* room for it beyond the ring size. Send completion notices its special |
|
* wr_id and avoids working with the ring in that case. |
|
*/ |
|
#ifndef KERNEL_HAS_ATOMIC64 |
|
void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required) |
|
{ |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&ic->i_ack_lock, flags); |
|
ic->i_ack_next = seq; |
|
if (ack_required) |
|
set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
|
spin_unlock_irqrestore(&ic->i_ack_lock, flags); |
|
} |
|
|
|
static u64 rds_ib_get_ack(struct rds_ib_connection *ic) |
|
{ |
|
unsigned long flags; |
|
u64 seq; |
|
|
|
clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
|
|
|
spin_lock_irqsave(&ic->i_ack_lock, flags); |
|
seq = ic->i_ack_next; |
|
spin_unlock_irqrestore(&ic->i_ack_lock, flags); |
|
|
|
return seq; |
|
} |
|
#else |
|
void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required) |
|
{ |
|
atomic64_set(&ic->i_ack_next, seq); |
|
if (ack_required) { |
|
smp_mb__before_atomic(); |
|
set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
|
} |
|
} |
|
|
|
static u64 rds_ib_get_ack(struct rds_ib_connection *ic) |
|
{ |
|
clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
|
smp_mb__after_atomic(); |
|
|
|
return atomic64_read(&ic->i_ack_next); |
|
} |
|
#endif |
|
|
|
|
|
static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credits) |
|
{ |
|
struct rds_header *hdr = ic->i_ack; |
|
u64 seq; |
|
int ret; |
|
|
|
seq = rds_ib_get_ack(ic); |
|
|
|
rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq); |
|
|
|
ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev, ic->i_ack_dma, |
|
sizeof(*hdr), DMA_TO_DEVICE); |
|
rds_message_populate_header(hdr, 0, 0, 0); |
|
hdr->h_ack = cpu_to_be64(seq); |
|
hdr->h_credit = adv_credits; |
|
rds_message_make_checksum(hdr); |
|
ib_dma_sync_single_for_device(ic->rds_ibdev->dev, ic->i_ack_dma, |
|
sizeof(*hdr), DMA_TO_DEVICE); |
|
|
|
ic->i_ack_queued = jiffies; |
|
|
|
ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, NULL); |
|
if (unlikely(ret)) { |
|
/* Failed to send. Release the WR, and |
|
* force another ACK. |
|
*/ |
|
clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); |
|
set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
|
|
|
rds_ib_stats_inc(s_ib_ack_send_failure); |
|
|
|
rds_ib_conn_error(ic->conn, "sending ack failed\n"); |
|
} else |
|
rds_ib_stats_inc(s_ib_ack_sent); |
|
} |
|
|
|
/* |
|
* There are 3 ways of getting acknowledgements to the peer: |
|
* 1. We call rds_ib_attempt_ack from the recv completion handler |
|
* to send an ACK-only frame. |
|
* However, there can be only one such frame in the send queue |
|
* at any time, so we may have to postpone it. |
|
* 2. When another (data) packet is transmitted while there's |
|
* an ACK in the queue, we piggyback the ACK sequence number |
|
* on the data packet. |
|
* 3. If the ACK WR is done sending, we get called from the |
|
* send queue completion handler, and check whether there's |
|
* another ACK pending (postponed because the WR was on the |
|
* queue). If so, we transmit it. |
|
* |
|
* We maintain 2 variables: |
|
* - i_ack_flags, which keeps track of whether the ACK WR |
|
* is currently in the send queue or not (IB_ACK_IN_FLIGHT) |
|
* - i_ack_next, which is the last sequence number we received |
|
* |
|
* Potentially, send queue and receive queue handlers can run concurrently. |
|
* It would be nice to not have to use a spinlock to synchronize things, |
|
* but the one problem that rules this out is that 64bit updates are |
|
* not atomic on all platforms. Things would be a lot simpler if |
|
* we had atomic64 or maybe cmpxchg64 everywhere. |
|
* |
|
* Reconnecting complicates this picture just slightly. When we |
|
* reconnect, we may be seeing duplicate packets. The peer |
|
* is retransmitting them, because it hasn't seen an ACK for |
|
* them. It is important that we ACK these. |
|
* |
|
* ACK mitigation adds a header flag "ACK_REQUIRED"; any packet with |
|
* this flag set *MUST* be acknowledged immediately. |
|
*/ |
|
|
|
/* |
|
* When we get here, we're called from the recv queue handler. |
|
* Check whether we ought to transmit an ACK. |
|
*/ |
|
void rds_ib_attempt_ack(struct rds_ib_connection *ic) |
|
{ |
|
unsigned int adv_credits; |
|
|
|
if (!test_bit(IB_ACK_REQUESTED, &ic->i_ack_flags)) |
|
return; |
|
|
|
if (test_and_set_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags)) { |
|
rds_ib_stats_inc(s_ib_ack_send_delayed); |
|
return; |
|
} |
|
|
|
/* Can we get a send credit? */ |
|
if (!rds_ib_send_grab_credits(ic, 1, &adv_credits, 0, RDS_MAX_ADV_CREDIT)) { |
|
rds_ib_stats_inc(s_ib_tx_throttle); |
|
clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); |
|
return; |
|
} |
|
|
|
clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags); |
|
rds_ib_send_ack(ic, adv_credits); |
|
} |
|
|
|
/* |
|
* We get here from the send completion handler, when the |
|
* adapter tells us the ACK frame was sent. |
|
*/ |
|
void rds_ib_ack_send_complete(struct rds_ib_connection *ic) |
|
{ |
|
clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags); |
|
rds_ib_attempt_ack(ic); |
|
} |
|
|
|
/* |
|
* This is called by the regular xmit code when it wants to piggyback |
|
* an ACK on an outgoing frame. |
|
*/ |
|
u64 rds_ib_piggyb_ack(struct rds_ib_connection *ic) |
|
{ |
|
if (test_and_clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags)) |
|
rds_ib_stats_inc(s_ib_ack_send_piggybacked); |
|
return rds_ib_get_ack(ic); |
|
} |
|
|
|
/* |
|
* It's kind of lame that we're copying from the posted receive pages into |
|
* long-lived bitmaps. We could have posted the bitmaps and rdma written into |
|
* them. But receiving new congestion bitmaps should be a *rare* event, so |
|
* hopefully we won't need to invest that complexity in making it more |
|
* efficient. By copying we can share a simpler core with TCP which has to |
|
* copy. |
|
*/ |
|
static void rds_ib_cong_recv(struct rds_connection *conn, |
|
struct rds_ib_incoming *ibinc) |
|
{ |
|
struct rds_cong_map *map; |
|
unsigned int map_off; |
|
unsigned int map_page; |
|
struct rds_page_frag *frag; |
|
unsigned long frag_off; |
|
unsigned long to_copy; |
|
unsigned long copied; |
|
__le64 uncongested = 0; |
|
void *addr; |
|
|
|
/* catch completely corrupt packets */ |
|
if (be32_to_cpu(ibinc->ii_inc.i_hdr.h_len) != RDS_CONG_MAP_BYTES) |
|
return; |
|
|
|
map = conn->c_fcong; |
|
map_page = 0; |
|
map_off = 0; |
|
|
|
frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item); |
|
frag_off = 0; |
|
|
|
copied = 0; |
|
|
|
while (copied < RDS_CONG_MAP_BYTES) { |
|
__le64 *src, *dst; |
|
unsigned int k; |
|
|
|
to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off); |
|
BUG_ON(to_copy & 7); /* Must be 64bit aligned. */ |
|
|
|
addr = kmap_atomic(sg_page(&frag->f_sg)); |
|
|
|
src = addr + frag->f_sg.offset + frag_off; |
|
dst = (void *)map->m_page_addrs[map_page] + map_off; |
|
for (k = 0; k < to_copy; k += 8) { |
|
/* Record ports that became uncongested, ie |
|
* bits that changed from 0 to 1. */ |
|
uncongested |= ~(*src) & *dst; |
|
*dst++ = *src++; |
|
} |
|
kunmap_atomic(addr); |
|
|
|
copied += to_copy; |
|
|
|
map_off += to_copy; |
|
if (map_off == PAGE_SIZE) { |
|
map_off = 0; |
|
map_page++; |
|
} |
|
|
|
frag_off += to_copy; |
|
if (frag_off == RDS_FRAG_SIZE) { |
|
frag = list_entry(frag->f_item.next, |
|
struct rds_page_frag, f_item); |
|
frag_off = 0; |
|
} |
|
} |
|
|
|
/* the congestion map is in little endian order */ |
|
rds_cong_map_updated(map, le64_to_cpu(uncongested)); |
|
} |
|
|
|
static void rds_ib_process_recv(struct rds_connection *conn, |
|
struct rds_ib_recv_work *recv, u32 data_len, |
|
struct rds_ib_ack_state *state) |
|
{ |
|
struct rds_ib_connection *ic = conn->c_transport_data; |
|
struct rds_ib_incoming *ibinc = ic->i_ibinc; |
|
struct rds_header *ihdr, *hdr; |
|
dma_addr_t dma_addr = ic->i_recv_hdrs_dma[recv - ic->i_recvs]; |
|
|
|
/* XXX shut down the connection if port 0,0 are seen? */ |
|
|
|
rdsdebug("ic %p ibinc %p recv %p byte len %u\n", ic, ibinc, recv, |
|
data_len); |
|
|
|
if (data_len < sizeof(struct rds_header)) { |
|
rds_ib_conn_error(conn, "incoming message " |
|
"from %pI6c didn't include a " |
|
"header, disconnecting and " |
|
"reconnecting\n", |
|
&conn->c_faddr); |
|
return; |
|
} |
|
data_len -= sizeof(struct rds_header); |
|
|
|
ihdr = ic->i_recv_hdrs[recv - ic->i_recvs]; |
|
|
|
ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev, dma_addr, |
|
sizeof(*ihdr), DMA_FROM_DEVICE); |
|
/* Validate the checksum. */ |
|
if (!rds_message_verify_checksum(ihdr)) { |
|
rds_ib_conn_error(conn, "incoming message " |
|
"from %pI6c has corrupted header - " |
|
"forcing a reconnect\n", |
|
&conn->c_faddr); |
|
rds_stats_inc(s_recv_drop_bad_checksum); |
|
goto done; |
|
} |
|
|
|
/* Process the ACK sequence which comes with every packet */ |
|
state->ack_recv = be64_to_cpu(ihdr->h_ack); |
|
state->ack_recv_valid = 1; |
|
|
|
/* Process the credits update if there was one */ |
|
if (ihdr->h_credit) |
|
rds_ib_send_add_credits(conn, ihdr->h_credit); |
|
|
|
if (ihdr->h_sport == 0 && ihdr->h_dport == 0 && data_len == 0) { |
|
/* This is an ACK-only packet. The fact that it gets |
|
* special treatment here is that historically, ACKs |
|
* were rather special beasts. |
|
*/ |
|
rds_ib_stats_inc(s_ib_ack_received); |
|
|
|
/* |
|
* Usually the frags make their way on to incs and are then freed as |
|
* the inc is freed. We don't go that route, so we have to drop the |
|
* page ref ourselves. We can't just leave the page on the recv |
|
* because that confuses the dma mapping of pages and each recv's use |
|
* of a partial page. |
|
* |
|
* FIXME: Fold this into the code path below. |
|
*/ |
|
rds_ib_frag_free(ic, recv->r_frag); |
|
recv->r_frag = NULL; |
|
goto done; |
|
} |
|
|
|
/* |
|
* If we don't already have an inc on the connection then this |
|
* fragment has a header and starts a message.. copy its header |
|
* into the inc and save the inc so we can hang upcoming fragments |
|
* off its list. |
|
*/ |
|
if (!ibinc) { |
|
ibinc = recv->r_ibinc; |
|
recv->r_ibinc = NULL; |
|
ic->i_ibinc = ibinc; |
|
|
|
hdr = &ibinc->ii_inc.i_hdr; |
|
ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] = |
|
local_clock(); |
|
memcpy(hdr, ihdr, sizeof(*hdr)); |
|
ic->i_recv_data_rem = be32_to_cpu(hdr->h_len); |
|
ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_START] = |
|
local_clock(); |
|
|
|
rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc, |
|
ic->i_recv_data_rem, hdr->h_flags); |
|
} else { |
|
hdr = &ibinc->ii_inc.i_hdr; |
|
/* We can't just use memcmp here; fragments of a |
|
* single message may carry different ACKs */ |
|
if (hdr->h_sequence != ihdr->h_sequence || |
|
hdr->h_len != ihdr->h_len || |
|
hdr->h_sport != ihdr->h_sport || |
|
hdr->h_dport != ihdr->h_dport) { |
|
rds_ib_conn_error(conn, |
|
"fragment header mismatch; forcing reconnect\n"); |
|
goto done; |
|
} |
|
} |
|
|
|
list_add_tail(&recv->r_frag->f_item, &ibinc->ii_frags); |
|
recv->r_frag = NULL; |
|
|
|
if (ic->i_recv_data_rem > RDS_FRAG_SIZE) |
|
ic->i_recv_data_rem -= RDS_FRAG_SIZE; |
|
else { |
|
ic->i_recv_data_rem = 0; |
|
ic->i_ibinc = NULL; |
|
|
|
if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP) { |
|
rds_ib_cong_recv(conn, ibinc); |
|
} else { |
|
rds_recv_incoming(conn, &conn->c_faddr, &conn->c_laddr, |
|
&ibinc->ii_inc, GFP_ATOMIC); |
|
state->ack_next = be64_to_cpu(hdr->h_sequence); |
|
state->ack_next_valid = 1; |
|
} |
|
|
|
/* Evaluate the ACK_REQUIRED flag *after* we received |
|
* the complete frame, and after bumping the next_rx |
|
* sequence. */ |
|
if (hdr->h_flags & RDS_FLAG_ACK_REQUIRED) { |
|
rds_stats_inc(s_recv_ack_required); |
|
state->ack_required = 1; |
|
} |
|
|
|
rds_inc_put(&ibinc->ii_inc); |
|
} |
|
done: |
|
ib_dma_sync_single_for_device(ic->rds_ibdev->dev, dma_addr, |
|
sizeof(*ihdr), DMA_FROM_DEVICE); |
|
} |
|
|
|
void rds_ib_recv_cqe_handler(struct rds_ib_connection *ic, |
|
struct ib_wc *wc, |
|
struct rds_ib_ack_state *state) |
|
{ |
|
struct rds_connection *conn = ic->conn; |
|
struct rds_ib_recv_work *recv; |
|
|
|
rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n", |
|
(unsigned long long)wc->wr_id, wc->status, |
|
ib_wc_status_msg(wc->status), wc->byte_len, |
|
be32_to_cpu(wc->ex.imm_data)); |
|
|
|
rds_ib_stats_inc(s_ib_rx_cq_event); |
|
recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)]; |
|
ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, |
|
DMA_FROM_DEVICE); |
|
|
|
/* Also process recvs in connecting state because it is possible |
|
* to get a recv completion _before_ the rdmacm ESTABLISHED |
|
* event is processed. |
|
*/ |
|
if (wc->status == IB_WC_SUCCESS) { |
|
rds_ib_process_recv(conn, recv, wc->byte_len, state); |
|
} else { |
|
/* We expect errors as the qp is drained during shutdown */ |
|
if (rds_conn_up(conn) || rds_conn_connecting(conn)) |
|
rds_ib_conn_error(conn, "recv completion on <%pI6c,%pI6c, %d> had status %u (%s), vendor err 0x%x, disconnecting and reconnecting\n", |
|
&conn->c_laddr, &conn->c_faddr, |
|
conn->c_tos, wc->status, |
|
ib_wc_status_msg(wc->status), |
|
wc->vendor_err); |
|
} |
|
|
|
/* rds_ib_process_recv() doesn't always consume the frag, and |
|
* we might not have called it at all if the wc didn't indicate |
|
* success. We already unmapped the frag's pages, though, and |
|
* the following rds_ib_ring_free() call tells the refill path |
|
* that it will not find an allocated frag here. Make sure we |
|
* keep that promise by freeing a frag that's still on the ring. |
|
*/ |
|
if (recv->r_frag) { |
|
rds_ib_frag_free(ic, recv->r_frag); |
|
recv->r_frag = NULL; |
|
} |
|
rds_ib_ring_free(&ic->i_recv_ring, 1); |
|
|
|
/* If we ever end up with a really empty receive ring, we're |
|
* in deep trouble, as the sender will definitely see RNR |
|
* timeouts. */ |
|
if (rds_ib_ring_empty(&ic->i_recv_ring)) |
|
rds_ib_stats_inc(s_ib_rx_ring_empty); |
|
|
|
if (rds_ib_ring_low(&ic->i_recv_ring)) { |
|
rds_ib_recv_refill(conn, 0, GFP_NOWAIT | __GFP_NOWARN); |
|
rds_ib_stats_inc(s_ib_rx_refill_from_cq); |
|
} |
|
} |
|
|
|
int rds_ib_recv_path(struct rds_conn_path *cp) |
|
{ |
|
struct rds_connection *conn = cp->cp_conn; |
|
struct rds_ib_connection *ic = conn->c_transport_data; |
|
|
|
rdsdebug("conn %p\n", conn); |
|
if (rds_conn_up(conn)) { |
|
rds_ib_attempt_ack(ic); |
|
rds_ib_recv_refill(conn, 0, GFP_KERNEL); |
|
rds_ib_stats_inc(s_ib_rx_refill_from_thread); |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
int rds_ib_recv_init(void) |
|
{ |
|
struct sysinfo si; |
|
int ret = -ENOMEM; |
|
|
|
/* Default to 30% of all available RAM for recv memory */ |
|
si_meminfo(&si); |
|
rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE; |
|
|
|
rds_ib_incoming_slab = |
|
kmem_cache_create_usercopy("rds_ib_incoming", |
|
sizeof(struct rds_ib_incoming), |
|
0, SLAB_HWCACHE_ALIGN, |
|
offsetof(struct rds_ib_incoming, |
|
ii_inc.i_usercopy), |
|
sizeof(struct rds_inc_usercopy), |
|
NULL); |
|
if (!rds_ib_incoming_slab) |
|
goto out; |
|
|
|
rds_ib_frag_slab = kmem_cache_create("rds_ib_frag", |
|
sizeof(struct rds_page_frag), |
|
0, SLAB_HWCACHE_ALIGN, NULL); |
|
if (!rds_ib_frag_slab) { |
|
kmem_cache_destroy(rds_ib_incoming_slab); |
|
rds_ib_incoming_slab = NULL; |
|
} else |
|
ret = 0; |
|
out: |
|
return ret; |
|
} |
|
|
|
void rds_ib_recv_exit(void) |
|
{ |
|
WARN_ON(atomic_read(&rds_ib_allocation)); |
|
|
|
kmem_cache_destroy(rds_ib_incoming_slab); |
|
kmem_cache_destroy(rds_ib_frag_slab); |
|
}
|
|
|