svn commit: r311831 - head/sys/dev/cxgbe

[Navdeep Parhar]

Author: np
Date: Mon Jan  9 22:18:08 2017
New Revision: 311831
URL: https://svnweb.freebsd.org/changeset/base/311831

Log:
  cxgbe(4): The wraparound logic in start_wrq_wr() should not get involved
  in work requests that end at the end of the descriptor ring, even though
  the pidx wraps around to 0.
  
  MFC after:	3 days

Modified:
  head/sys/dev/cxgbe/t4_sge.c

Modified: head/sys/dev/cxgbe/t4_sge.c
==============================================================================
--- head/sys/dev/cxgbe/t4_sge.c	Mon Jan  9 21:46:24 2017	(r311830)
+++ head/sys/dev/cxgbe/t4_sge.c	Mon Jan  9 22:18:08 2017	(r311831)
@@ -2298,7 +2298,7 @@ slowpath:
 
 	w = &eq->desc[eq->pidx];
 	IDXINCR(eq->pidx, ndesc, eq->sidx);
-	if (__predict_false(eq->pidx < ndesc - 1)) {
+	if (__predict_false(cookie->pidx + ndesc > eq->sidx)) {
 		w = &wrq->ss[0];
 		wrq->ss_pidx = cookie->pidx;
 		wrq->ss_len = len16 * 16;