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[IB] srp: don't post receive if no send buf available

Have __srp_get_tx_iu() fail if the target port's request limit will
not allow the initiator to post a send.  This avoids continuing on and
posting a receive, and then failing to post a corresponding send.  If
that happens, then the initiator will end up with an extra receive
posted, and if this happens to much, the receive queue will overflow.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Roland Dreier 2005-11-15 00:19:21 -08:00
parent 5f068992a1
commit 47f2bce902
1 changed files with 9 additions and 6 deletions

View File

@ -802,13 +802,21 @@ static int srp_post_recv(struct srp_target_port *target)
/*
* Must be called with target->scsi_host->host_lock held to protect
* req_lim and tx_head.
* req_lim and tx_head. Lock cannot be dropped between call here and
* call to __srp_post_send().
*/
static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target)
{
if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)
return NULL;
if (unlikely(target->req_lim < 1)) {
if (printk_ratelimit())
printk(KERN_DEBUG PFX "Target has req_lim %d\n",
target->req_lim);
return NULL;
}
return target->tx_ring[target->tx_head & SRP_SQ_SIZE];
}
@ -823,11 +831,6 @@ static int __srp_post_send(struct srp_target_port *target,
struct ib_send_wr wr, *bad_wr;
int ret = 0;
if (target->req_lim < 1) {
printk(KERN_ERR PFX "Target has req_lim %d\n", target->req_lim);
return -EAGAIN;
}
list.addr = iu->dma;
list.length = len;
list.lkey = target->srp_host->mr->lkey;