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authorRoland Dreier <rolandd@cisco.com>2005-11-15 00:19:21 -0800
committerRoland Dreier <rolandd@cisco.com>2005-11-15 00:19:21 -0800
commit47f2bce9021b4974ed33b072ebb8348c8145c946 (patch)
tree2d17f2cdc77646d07cb2a598e3d2bcbdf94675ad /drivers/infiniband/ulp/srp/ib_srp.c
parent5f068992a1bccda5574b4f6d33458ef806686d7f (diff)
downloadlwn-47f2bce9021b4974ed33b072ebb8348c8145c946.tar.gz
lwn-47f2bce9021b4974ed33b072ebb8348c8145c946.zip
[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>
Diffstat (limited to 'drivers/infiniband/ulp/srp/ib_srp.c')
-rw-r--r--drivers/infiniband/ulp/srp/ib_srp.c15
1 files 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;