[openib-general] [git patch review 2/3] [IB] srp: don't post receive if no send buf available
Roland Dreier
rolandd at cisco.com
Tue Nov 15 00:38:30 PST 2005
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 at cisco.com>
---
drivers/infiniband/ulp/srp/ib_srp.c | 15 +++++++++------
1 files changed, 9 insertions(+), 6 deletions(-)
applies-to: a5f8266c59f39f0a1f3dc3d71a00da7276ac1a80
47f2bce9021b4974ed33b072ebb8348c8145c946
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index a364530..ee9fe22 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_targ
/*
* 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_ta
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;
---
0.99.9g
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