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![Marciniszyn, Mike](/assets/img/avatar_default.png)
0b088e00
("RDS: Use page_remainder_alloc() for recv bufs")
added uses of sg_dma_len() and sg_dma_address(). This makes
RDS DOA with the qib driver.
IB ulps should use ib_sg_dma_len() and ib_sg_dma_address
respectively since some HCAs overload ib_sg_dma* operations.
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1080 lines
30 KiB
C
1080 lines
30 KiB
C
/*
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* Copyright (c) 2006 Oracle. 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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#include "rds.h"
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#include "ib.h"
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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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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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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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recv->r_ibinc = NULL;
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recv->r_frag = NULL;
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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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sge = &recv->r_sge[0];
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sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header));
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sge->length = sizeof(struct rds_header);
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sge->lkey = ic->i_mr->lkey;
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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_mr->lkey;
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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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list_splice_tail(from_last, to);
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list_add_tail(from_last, to);
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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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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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static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache)
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{
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struct rds_ib_cache_head *head;
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int cpu;
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cache->percpu = alloc_percpu(struct rds_ib_cache_head);
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if (!cache->percpu)
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return -ENOMEM;
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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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return 0;
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}
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int rds_ib_recv_alloc_caches(struct rds_ib_connection *ic)
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{
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int ret;
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ret = rds_ib_recv_alloc_cache(&ic->i_cache_incs);
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if (!ret) {
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ret = rds_ib_recv_alloc_cache(&ic->i_cache_frags);
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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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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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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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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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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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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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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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}
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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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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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/* 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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/* 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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rds_ib_recv_cache_put(&frag->f_cache_entry, &ic->i_cache_frags);
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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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ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
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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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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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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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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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}
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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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return ibinc;
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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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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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} 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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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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}
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INIT_LIST_HEAD(&frag->f_item);
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return frag;
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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, int prefill)
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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_NOWAIT;
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gfp_t page_mask = GFP_NOWAIT;
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if (prefill) {
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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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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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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) * sizeof(struct rds_header);
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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 = ib_sg_dma_address(ic->i_cm_id->device, &recv->r_frag->f_sg);
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sge->length = ib_sg_dma_len(ic->i_cm_id->device, &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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/*
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* This tries to allocate and post unused work requests after making sure that
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* they have all the allocations they need to queue received fragments into
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* sockets.
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*
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* -1 is returned if posting fails due to temporary resource exhaustion.
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*/
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void rds_ib_recv_refill(struct rds_connection *conn, int prefill)
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{
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struct rds_ib_connection *ic = conn->c_transport_data;
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struct rds_ib_recv_work *recv;
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struct ib_recv_wr *failed_wr;
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unsigned int posted = 0;
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int ret = 0;
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u32 pos;
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while ((prefill || rds_conn_up(conn)) &&
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rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
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if (pos >= ic->i_recv_ring.w_nr) {
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printk(KERN_NOTICE "Argh - ring alloc returned pos=%u\n",
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pos);
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break;
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}
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recv = &ic->i_recvs[pos];
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ret = rds_ib_recv_refill_one(conn, recv, prefill);
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if (ret) {
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break;
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}
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/* XXX when can this fail? */
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ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
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rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv,
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recv->r_ibinc, sg_page(&recv->r_frag->f_sg),
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(long) ib_sg_dma_address(
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ic->i_cm_id->device,
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&recv->r_frag->f_sg),
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ret);
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if (ret) {
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rds_ib_conn_error(conn, "recv post on "
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"%pI4 returned %d, disconnecting and "
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"reconnecting\n", &conn->c_faddr,
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ret);
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break;
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}
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posted++;
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}
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/* We're doing flow control - update the window. */
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if (ic->i_flowctl && posted)
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rds_ib_advertise_credits(conn, posted);
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if (ret)
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rds_ib_ring_unalloc(&ic->i_recv_ring, 1);
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}
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/*
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* We want to recycle several types of recv allocations, like incs and frags.
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* To use this, the *_free() function passes in the ptr to a list_head within
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* the recyclee, as well as the cache to put it on.
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*
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* First, we put the memory on a percpu list. When this reaches a certain size,
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* We move it to an intermediate non-percpu list in a lockless manner, with some
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* xchg/compxchg wizardry.
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*
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* N.B. Instead of a list_head as the anchor, we use a single pointer, which can
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* be NULL and xchg'd. The list is actually empty when the pointer is NULL, and
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* list_empty() will return true with one element is actually present.
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*/
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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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{
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unsigned long flags;
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struct list_head *old;
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struct list_head __percpu *chpfirst;
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local_irq_save(flags);
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chpfirst = __this_cpu_read(cache->percpu->first);
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if (!chpfirst)
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INIT_LIST_HEAD(new_item);
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else /* put on front */
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list_add_tail(new_item, chpfirst);
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__this_cpu_write(chpfirst, new_item);
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__this_cpu_inc(cache->percpu->count);
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if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
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goto end;
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/*
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* Return our per-cpu first list to the cache's xfer by atomically
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* grabbing the current xfer list, appending it to our per-cpu list,
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* and then atomically returning that entire list back to the
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* cache's xfer list as long as it's still empty.
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*/
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do {
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old = xchg(&cache->xfer, NULL);
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if (old)
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list_splice_entire_tail(old, chpfirst);
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old = cmpxchg(&cache->xfer, NULL, chpfirst);
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} while (old);
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__this_cpu_write(chpfirst, NULL);
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__this_cpu_write(cache->percpu->count, 0);
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end:
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local_irq_restore(flags);
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}
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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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struct list_head *head = cache->ready;
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if (head) {
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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 iovec *first_iov,
|
|
size_t size)
|
|
{
|
|
struct rds_ib_incoming *ibinc;
|
|
struct rds_page_frag *frag;
|
|
struct iovec *iov = first_iov;
|
|
unsigned long to_copy;
|
|
unsigned long frag_off = 0;
|
|
unsigned long iov_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 (copied < size && copied < len) {
|
|
if (frag_off == RDS_FRAG_SIZE) {
|
|
frag = list_entry(frag->f_item.next,
|
|
struct rds_page_frag, f_item);
|
|
frag_off = 0;
|
|
}
|
|
while (iov_off == iov->iov_len) {
|
|
iov_off = 0;
|
|
iov++;
|
|
}
|
|
|
|
to_copy = min(iov->iov_len - iov_off, RDS_FRAG_SIZE - frag_off);
|
|
to_copy = min_t(size_t, to_copy, size - copied);
|
|
to_copy = min_t(unsigned long, to_copy, len - copied);
|
|
|
|
rdsdebug("%lu bytes to user [%p, %zu] + %lu from frag "
|
|
"[%p, %u] + %lu\n",
|
|
to_copy, iov->iov_base, iov->iov_len, iov_off,
|
|
sg_page(&frag->f_sg), frag->f_sg.offset, frag_off);
|
|
|
|
/* XXX needs + offset for multiple recvs per page */
|
|
ret = rds_page_copy_to_user(sg_page(&frag->f_sg),
|
|
frag->f_sg.offset + frag_off,
|
|
iov->iov_base + iov_off,
|
|
to_copy);
|
|
if (ret) {
|
|
copied = ret;
|
|
break;
|
|
}
|
|
|
|
iov_off += to_copy;
|
|
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_mr->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
|
|
static 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
|
|
static 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_clear_bit();
|
|
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_clear_bit();
|
|
|
|
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;
|
|
struct ib_send_wr *failed_wr;
|
|
u64 seq;
|
|
int ret;
|
|
|
|
seq = rds_ib_get_ack(ic);
|
|
|
|
rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
|
|
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);
|
|
ic->i_ack_queued = jiffies;
|
|
|
|
ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr);
|
|
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;
|
|
uint64_t 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) {
|
|
uint64_t *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_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 */
|
|
uncongested = le64_to_cpu(uncongested);
|
|
|
|
rds_cong_map_updated(map, uncongested);
|
|
}
|
|
|
|
/*
|
|
* Rings are posted with all the allocations they'll need to queue the
|
|
* incoming message to the receiving socket so this can't fail.
|
|
* All fragments start with a header, so we can make sure we're not receiving
|
|
* garbage, and we can tell a small 8 byte fragment from an ACK frame.
|
|
*/
|
|
struct rds_ib_ack_state {
|
|
u64 ack_next;
|
|
u64 ack_recv;
|
|
unsigned int ack_required:1;
|
|
unsigned int ack_next_valid:1;
|
|
unsigned int ack_recv_valid:1;
|
|
};
|
|
|
|
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;
|
|
|
|
/* 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 %pI4 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];
|
|
|
|
/* Validate the checksum. */
|
|
if (!rds_message_verify_checksum(ihdr)) {
|
|
rds_ib_conn_error(conn, "incoming message "
|
|
"from %pI4 has corrupted header - "
|
|
"forcing a reconnect\n",
|
|
&conn->c_faddr);
|
|
rds_stats_inc(s_recv_drop_bad_checksum);
|
|
return;
|
|
}
|
|
|
|
/* 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;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
memcpy(hdr, ihdr, sizeof(*hdr));
|
|
ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
|
|
|
|
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");
|
|
return;
|
|
}
|
|
}
|
|
|
|
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);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Plucking the oldest entry from the ring can be done concurrently with
|
|
* the thread refilling the ring. Each ring operation is protected by
|
|
* spinlocks and the transient state of refilling doesn't change the
|
|
* recording of which entry is oldest.
|
|
*
|
|
* This relies on IB only calling one cq comp_handler for each cq so that
|
|
* there will only be one caller of rds_recv_incoming() per RDS connection.
|
|
*/
|
|
void rds_ib_recv_cq_comp_handler(struct ib_cq *cq, void *context)
|
|
{
|
|
struct rds_connection *conn = context;
|
|
struct rds_ib_connection *ic = conn->c_transport_data;
|
|
|
|
rdsdebug("conn %p cq %p\n", conn, cq);
|
|
|
|
rds_ib_stats_inc(s_ib_rx_cq_call);
|
|
|
|
tasklet_schedule(&ic->i_recv_tasklet);
|
|
}
|
|
|
|
static inline void rds_poll_cq(struct rds_ib_connection *ic,
|
|
struct rds_ib_ack_state *state)
|
|
{
|
|
struct rds_connection *conn = ic->conn;
|
|
struct ib_wc wc;
|
|
struct rds_ib_recv_work *recv;
|
|
|
|
while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) {
|
|
rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
|
|
(unsigned long long)wc.wr_id, wc.status,
|
|
rds_ib_wc_status_str(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 %pI4 had "
|
|
"status %u (%s), disconnecting and "
|
|
"reconnecting\n", &conn->c_faddr,
|
|
wc.status,
|
|
rds_ib_wc_status_str(wc.status));
|
|
}
|
|
|
|
/*
|
|
* It's very important that we only free this ring entry if we've truly
|
|
* freed the resources allocated to the entry. The refilling path can
|
|
* leak if we don't.
|
|
*/
|
|
rds_ib_ring_free(&ic->i_recv_ring, 1);
|
|
}
|
|
}
|
|
|
|
void rds_ib_recv_tasklet_fn(unsigned long data)
|
|
{
|
|
struct rds_ib_connection *ic = (struct rds_ib_connection *) data;
|
|
struct rds_connection *conn = ic->conn;
|
|
struct rds_ib_ack_state state = { 0, };
|
|
|
|
rds_poll_cq(ic, &state);
|
|
ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED);
|
|
rds_poll_cq(ic, &state);
|
|
|
|
if (state.ack_next_valid)
|
|
rds_ib_set_ack(ic, state.ack_next, state.ack_required);
|
|
if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) {
|
|
rds_send_drop_acked(conn, state.ack_recv, NULL);
|
|
ic->i_ack_recv = state.ack_recv;
|
|
}
|
|
if (rds_conn_up(conn))
|
|
rds_ib_attempt_ack(ic);
|
|
|
|
/* 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);
|
|
}
|
|
|
|
int rds_ib_recv(struct rds_connection *conn)
|
|
{
|
|
struct rds_ib_connection *ic = conn->c_transport_data;
|
|
int ret = 0;
|
|
|
|
rdsdebug("conn %p\n", conn);
|
|
if (rds_conn_up(conn))
|
|
rds_ib_attempt_ack(ic);
|
|
|
|
return ret;
|
|
}
|
|
|
|
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("rds_ib_incoming",
|
|
sizeof(struct rds_ib_incoming),
|
|
0, SLAB_HWCACHE_ALIGN, 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);
|
|
else
|
|
ret = 0;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
void rds_ib_recv_exit(void)
|
|
{
|
|
kmem_cache_destroy(rds_ib_incoming_slab);
|
|
kmem_cache_destroy(rds_ib_frag_slab);
|
|
}
|