From 47f2bce9021b4974ed33b072ebb8348c8145c946 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Tue, 15 Nov 2005 00:19:21 -0800 Subject: [PATCH] [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 --- drivers/infiniband/ulp/srp/ib_srp.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index a3645303cb99..ee9fe226ae99 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -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; -- 2.20.1