From: Wei Lin Guay <wei.lin.guay@oracle.com>
Date: Thu, 3 Nov 2016 09:46:22 +0000 (+0100)
Subject: sif: cq: sif_poll_cq might not drain cq completely
X-Git-Tag: v4.1.12-92~36^2~8
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=c2cf0f102632f1fe3531d7beaba5aeb68fbfdaf3;p=users%2Fjedix%2Flinux-maple.git

sif: cq: sif_poll_cq might not drain cq completely

In a scenario where a duplicate completion is detected, the sif_poll_cq
skips the remaining cqes in the cq. This code bug is introduced in
commit "sif: sqflush: Handle duplicate completions in poll_cq".

Orabug: 25038711

Signed-off-by: Wei Lin Guay <wei.lin.guay@oracle.com>
Reviewed-by: Knut Omang <knut.omang@oracle.com>
---

diff --git a/drivers/infiniband/hw/sif/sif_cq.c b/drivers/infiniband/hw/sif/sif_cq.c
index 92204edbdb75..545a7fe702fc 100644
--- a/drivers/infiniband/hw/sif/sif_cq.c
+++ b/drivers/infiniband/hw/sif/sif_cq.c
@@ -871,25 +871,23 @@ int sif_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc)
 
 		polled_value = get_psif_cq_entry__seq_num(cqe);
 
-		if (seqno == polled_value)
-			npolled++;
-		else
+		if (seqno != polled_value)
 			break;
 
 		if (likely(wc)) {
-			if (unlikely(handle_wc(sdev, cq, cqe, wc) < 0)) {
-				/* poll_cq should not return < 0. Thus, ignore
-				 * the CQE if it is duplicate, unexpected or wrong
-				 * CQE.
-				 */
-				seqno = ++cq_sw->next_seq;
-				npolled--;
-				continue;
+			 /* handle_wc == 0 means that it's a valid cqe.
+			  * Thus, increments the npolled and the wc pointer.
+			  */
+			if (likely(handle_wc(sdev, cq, cqe, wc) == 0)) {
+				++wc;
+				++npolled;
 			}
-			wc++;
 			seqno = ++cq_sw->next_seq;
-		} else /* peek_cq semantics */
+		} else {
+			/* peek_cq semantics */
 			++seqno;
+			++npolled;
+		}
 
 		cqe = get_cq_entry(cq, seqno);
 	}