dma-buf/fence: fix fence_is_later v2

ChristianKoenigAMD · danvet · commit b47bcb93bbf2 · 2016-03-21T09:26:50.000+01:00
A fence is never later than itself. This caused a bunch of overhead for AMDGPU.

v2: simplify check as suggested by Michel.

Signed-off-by: Christian König &lt;christian.koenig@amd.com&gt;
Reviewed-by: Michel Dänzer &lt;michel.daenzer@amd.com&gt;
Reviewed-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Reviewed-by: Gustavo Padovan &lt;gustavo.padovan@collabora.co.uk&gt;
Reviewed-by: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Signed-off-by: Alex Deucher &lt;alexander.deucher@amd.com&gt;
Signed-off-by: Sumit Semwal &lt;sumit.semwal@linaro.org&gt;
Signed-off-by: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
diff --git a/include/linux/fence.h b/include/linux/fence.h
@@ -292,7 +292,7 @@ static inline bool fence_is_later(struct fence *f1, struct fence *f2)
 	if (WARN_ON(f1->context != f2->context))
 		return false;
 
-	return f1->seqno - f2->seqno < INT_MAX;
+	return (int)(f1->seqno - f2->seqno) > 0;
 }
 
 /**

Original file line number	Diff line number	Diff line change
`@@ -292,7 +292,7 @@ static inline bool fence_is_later(struct fence f1, struct fence f2)`
`292`	`292`	`if (WARN_ON(f1->context != f2->context))`
`293`	`293`	`return false;`
`294`	`294`
`295`		`- return f1->seqno - f2->seqno < INT_MAX;`
	`295`	`+ return (int)(f1->seqno - f2->seqno) > 0;`
`296`	`296`	`}`
`297`	`297`
`298`	`298`	`/**`