From: Stephane Viau <sviau@codeaurora.org>
Date: Fri, 16 Jan 2015 18:22:14 +0000 (-0500)
Subject: drm/msm/mdp5: Fix negative SMP block allocation
X-Git-Tag: v4.0-rc1~74^2~11^2~2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2559d19f7650f08122747e7df2bf30e77c62674c;p=platform%2Fkernel%2Flinux-exynos.git

drm/msm/mdp5: Fix negative SMP block allocation

In case we request a number of SMP blocks which is lower than
the already reserved blocks, we should not try to allocate a
negative number, but 0 blocks instead.

Signed-off-by: Stephane Viau <sviau@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
---

diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_smp.c b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_smp.c
index bf55188..1f795af 100644
--- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_smp.c
+++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_smp.c
@@ -119,9 +119,10 @@ static int smp_request_block(struct mdp5_smp *smp,
 
 	spin_lock_irqsave(&smp->state_lock, flags);
 
-	nblks -= reserved;
-	if (reserved)
+	if (reserved) {
+		nblks = max(0, nblks - reserved);
 		DBG("%d MMBs allocated (%d reserved)", nblks, reserved);
+	}
 
 	avail = cnt - bitmap_weight(smp->state, cnt);
 	if (nblks > avail) {