diff mbox

[rdma-core,v4,1/4] ibacm: Fix an incorrect expiration check for the retry timer

Message ID 20171115193430.470.61687.stgit@phlsvslse11.ph.intel.com (mailing list archive)
State Accepted
Headers show

Commit Message

Michael J. Ruhl Nov. 15, 2017, 7:34 p.m. UTC 
From: Michael J. Ruhl <michael.j.ruhl@intel.com>

The acmp_process_wait_queue() checks to see if a message expiration
time has passed.

Because the check is for less than (<), if the timeout expires matches
the current time, the check will result in a timeout value of 0, and
the wait loop will spin until the next millisecond has passed.

Using example values to demonstrate the issue, we can see:

With '<':
wait = -2106577636 (no work)
wait = 2510        (message wait)
(process spins)
wait = 0           (expires - current time == 0)
wait = 0
wait = 0
...                (1 ms of output)
wait = 0
wait = -2106580147 (retry complete)
wait = 2512

With '<=':
wait = -2106688780 (no work)
wait = 2512        ( message wait)
(process sleeps)
wait = -2106691293 (retry complete)
wait = 2512

Expire the message if the expires is less than or equal.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
---
 ibacm/prov/acmp/src/acmp.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)


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diff mbox

Patch

diff --git a/ibacm/prov/acmp/src/acmp.c b/ibacm/prov/acmp/src/acmp.c
index 78d9a29..d707b8e 100644
--- a/ibacm/prov/acmp/src/acmp.c
+++ b/ibacm/prov/acmp/src/acmp.c
@@ -1507,7 +1507,7 @@  static void acmp_process_wait_queue(struct acmp_ep *ep, uint64_t *next_expire)
 	struct ibv_send_wr *bad_wr;
 
 	list_for_each_safe(&ep->wait_queue, msg, next, entry) {
-		if (msg->expires < time_stamp_ms()) {
+		if (msg->expires <= time_stamp_ms()) {
 			list_del(&msg->entry);
 			(void) atomic_dec(&wait_cnt);
 			if (--msg->tries) {