- 根目录:
- net
- rds
- ib_recv.c
/*
* Copyright (c) 2006 Oracle. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <rdma/rdma_cm.h>
#include "rds.h"
#include "ib.h"
static struct kmem_cache *rds_ib_incoming_slab;
static struct kmem_cache *rds_ib_frag_slab;
static atomic_t rds_ib_allocation = ATOMIC_INIT(0);
void rds_ib_recv_init_ring(struct rds_ib_connection *ic)
{
struct rds_ib_recv_work *recv;
u32 i;
for (i = 0, recv = ic->i_recvs; i < ic->i_recv_ring.w_nr; i++, recv++) {
struct ib_sge *sge;
recv->r_ibinc = NULL;
recv->r_frag = NULL;
recv->r_wr.next = NULL;
recv->r_wr.wr_id = i;
recv->r_wr.sg_list = recv->r_sge;
recv->r_wr.num_sge = RDS_IB_RECV_SGE;
sge = &recv->r_sge[0];
sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header));
sge->length = sizeof(struct rds_header);
sge->lkey = ic->i_mr->lkey;
sge = &recv->r_sge[1];
sge->addr = 0;
sge->length = RDS_FRAG_SIZE;
sge->lkey = ic->i_mr->lkey;
}
}
/*
* The entire 'from' list, including the from element itself, is put on
* to the tail of the 'to' list.
*/
static void list_splice_entire_tail(struct list_head *from,
struct list_head *to)
{
struct list_head *from_last = from->prev;
list_splice_tail(from_last, to);
list_add_tail(from_last, to);
}
static void rds_ib_cache_xfer_to_ready(struct rds_ib_refill_cache *cache)
{
struct list_head *tmp;
tmp = xchg(&cache->xfer, NULL);
if (tmp) {
if (cache->ready)
list_splice_entire_tail(tmp, cache->ready);
else
cache->ready = tmp;
}
}
static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache)
{
struct rds_ib_cache_head *head;
int cpu;
cache->percpu = alloc_percpu(struct rds_ib_cache_head);
if (!cache->percpu)
return -ENOMEM;
for_each_possible_cpu(cpu) {
head = per_cpu_ptr(cache->percpu, cpu);
head->first = NULL;
head->count = 0;
}
cache->xfer = NULL;
cache->ready = NULL;
return 0;
}
int rds_ib_recv_alloc_caches(struct rds_ib_connection *ic)
{
int ret;
ret = rds_ib_recv_alloc_cache(&ic->i_cache_incs);
if (!ret) {
ret = rds_ib_recv_alloc_cache(&ic->i_cache_frags);
if (ret)
free_percpu(ic->i_cache_incs.percpu);
}
return ret;
}
static void rds_ib_cache_splice_all_lists(struct rds_ib_refill_cache *cache,
struct list_head *caller_list)
{
struct rds_ib_cache_head *head;
int cpu;
for_each_possible_cpu(cpu) {
head = per_cpu_ptr(cache->percpu, cpu);
if (head->first) {
list_splice_entire_tail(head->first, caller_list);
head->first = NULL;
}
}
if (cache->ready) {
list_splice_entire_tail(cache->ready, caller_list);
cache->ready = NULL;
}
}
void rds_ib_recv_free_caches(struct rds_ib_connection *ic)
{
struct rds_ib_incoming *inc;
struct rds_ib_incoming *inc_tmp;
struct rds_page_frag *frag;
struct rds_page_frag *frag_tmp;
LIST_HEAD(list);
rds_ib_cache_xfer_to_ready(&ic->i_cache_incs);
rds_ib_cache_splice_all_lists(&ic->i_cache_incs, &list);
free_percpu(ic->i_cache_incs.percpu);
list_for_each_entry_safe(inc, inc_tmp, &list, ii_cache_entry) {
list_del(&inc->ii_cache_entry);
WARN_ON(!list_empty(&inc->ii_frags));
kmem_cache_free(rds_ib_incoming_slab, inc);
}
rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
rds_ib_cache_splice_all_lists(&ic->i_cache_frags, &list);
free_percpu(ic->i_cache_frags.percpu);
list_for_each_entry_safe(frag, frag_tmp, &list, f_cache_entry) {
list_del(&frag->f_cache_entry);
WARN_ON(!list_empty(&frag->f_item));
kmem_cache_free(rds_ib_frag_slab, frag);
}
}
/* fwd decl */
static void rds_ib_recv_cache_put(struct list_head *new_item,
struct rds_ib_refill_cache *cache);
static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache);
/* Recycle frag and attached recv buffer f_sg */
static void rds_ib_frag_free(struct rds_ib_connection *ic,
struct rds_page_frag *frag)
{
rdsdebug("frag %p page %p\n", frag, sg_page(&frag->f_sg));
rds_ib_recv_cache_put(&frag->f_cache_entry, &ic->i_cache_frags);
}
/* Recycle inc after freeing attached frags */
void rds_ib_inc_free(struct rds_incoming *inc)
{
struct rds_ib_incoming *ibinc;
struct rds_page_frag *frag;
struct rds_page_frag *pos;
struct rds_ib_connection *ic = inc->i_conn->c_transport_data;
ibinc = container_of(inc, struct rds_ib_incoming, ii_inc);
/* Free attached frags */
list_for_each_entry_safe(frag, pos, &ibinc->ii_frags, f_item) {
list_del_init(&frag->f_item);
rds_ib_frag_free(ic, frag);
}
BUG_ON(!list_empty(&ibinc->ii_frags));
rdsdebug("freeing ibinc %p inc %p\n", ibinc, inc);
rds_ib_recv_cache_put(&ibinc->ii_cache_entry, &ic->i_cache_incs);
}
static void rds_ib_recv_clear_one(struct rds_ib_connection *ic,
struct rds_ib_recv_work *recv)
{
if (recv->r_ibinc) {
rds_inc_put(&recv->r_ibinc->ii_inc);
recv->r_ibinc = NULL;
}
if (recv->r_frag) {
ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE);
rds_ib_frag_free(ic, recv->r_frag);
recv->r_frag = NULL;
}
}
void rds_ib_recv_clear_ring(struct rds_ib_connection *ic)
{
u32 i;
for (i = 0; i < ic->i_recv_ring.w_nr; i++)
rds_ib_recv_clear_one(ic, &ic->i_recvs[i]);
}
static struct rds_ib_incoming *rds_ib_refill_one_inc(struct rds_ib_connection *ic,
gfp_t slab_mask)
{
struct rds_ib_incoming *ibinc;
struct list_head *cache_item;
int avail_allocs;
cache_item = rds_ib_recv_cache_get(&ic->i_cache_incs);
if (cache_item) {
ibinc = container_of(cache_item, struct rds_ib_incoming, ii_cache_entry);
} else {
avail_allocs = atomic_add_unless(&rds_ib_allocation,
1, rds_ib_sysctl_max_recv_allocation);
if (!avail_allocs) {
rds_ib_stats_inc(s_ib_rx_alloc_limit);
return NULL;
}
ibinc = kmem_cache_alloc(rds_ib_incoming_slab, slab_mask);
if (!ibinc) {
atomic_dec(&rds_ib_allocation);
return NULL;
}
}
INIT_LIST_HEAD(&ibinc->ii_frags);
rds_inc_init(&ibinc->ii_inc, ic->conn, ic->conn->c_faddr);
return ibinc;
}
static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic,
gfp_t slab_mask, gfp_t page_mask)
{
struct rds_page_frag *frag;
struct list_head *cache_item;
int ret;
cache_item = rds_ib_recv_cache_get(&ic->i_cache_frags);
if (cache_item) {
frag = container_of(cache_item, struct rds_page_frag, f_cache_entry);
} else {
frag = kmem_cache_alloc(rds_ib_frag_slab, slab_mask);
if (!frag)
return NULL;
sg_init_table(&frag->f_sg, 1);
ret = rds_page_remainder_alloc(&frag->f_sg,
RDS_FRAG_SIZE, page_mask);
if (ret) {
kmem_cache_free(rds_ib_frag_slab, frag);
return NULL;
}
}
INIT_LIST_HEAD(&frag->f_item);
return frag;
}
static int rds_ib_recv_refill_one(struct rds_connection *conn,
struct rds_ib_recv_work *recv, int prefill)
{
struct rds_ib_connection *ic = conn->c_transport_data;
struct ib_sge *sge;
int ret = -ENOMEM;
gfp_t slab_mask = GFP_NOWAIT;
gfp_t page_mask = GFP_NOWAIT;
if (prefill) {
slab_mask = GFP_KERNEL;
page_mask = GFP_HIGHUSER;
}
if (!ic->i_cache_incs.ready)
rds_ib_cache_xfer_to_ready(&ic->i_cache_incs);
if (!ic->i_cache_frags.ready)
rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
/*
* ibinc was taken from recv if recv contained the start of a message.
* recvs that were continuations will still have this allocated.
*/
if (!recv->r_ibinc) {
recv->r_ibinc = rds_ib_refill_one_inc(ic, slab_mask);
if (!recv->r_ibinc)
goto out;
}
WARN_ON(recv->r_frag); /* leak! */
recv->r_frag = rds_ib_refill_one_frag(ic, slab_mask, page_mask);
if (!recv->r_frag)
goto out;
ret = ib_dma_map_sg(ic->i_cm_id->device, &recv->r_frag->f_sg,
1, DMA_FROM_DEVICE);
WARN_ON(ret != 1);
sge = &recv->r_sge[0];
sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header);
sge->length = sizeof(struct rds_header);
sge = &recv->r_sge[1];
sge->addr = sg_dma_address(&recv->r_frag->f_sg);
sge->length = sg_dma_len(&recv->r_frag->f_sg);
ret = 0;
out:
return ret;
}
/*
* 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.
*
* -1 is returned if posting fails due to temporary resource exhaustion.
*/
void rds_ib_recv_refill(struct rds_connection *conn, int prefill)
{
struct rds_ib_connection *ic = conn->c_transport_data;
struct rds_ib_recv_work *recv;
struct ib_recv_wr *failed_wr;
unsigned int posted = 0;
int ret = 0;
u32 pos;
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, prefill);
if (ret) {
break;
}
/* XXX when can this fail? */
ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv,
recv->r_ibinc, sg_page(&recv->r_frag->f_sg),
(long) sg_dma_address(&recv->r_frag->f_sg), ret);
if (ret) {
rds_ib_conn_error(conn, "recv post on "
"%pI4 returned %d, disconnecting and "
"reconnecting\n", &conn->c_faddr,
ret);
break;
}
posted++;
}
/* 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);
}
/*
* 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 rds_ib_cache_head *chp;
struct list_head *old;
local_irq_save(flags);
chp = per_cpu_ptr(cache->percpu, smp_processor_id());
if (!chp->first)
INIT_LIST_HEAD(new_item);
else /* put on front */
list_add_tail(new_item, chp->first);
chp->first = new_item;
chp->count++;
if (chp->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, chp->first);
old = cmpxchg(&cache->xfer, NULL, chp->first);
} while (old);
chp->first = NULL;
chp->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 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), KM_SOFTIRQ0);
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, KM_SOFTIRQ0);
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 inclue 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,
KM_SOFTIRQ0);
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);
}