[PATCH 4.10 66/75] drm/i915: Pass timeout==0 on to i915_gem_object_wait_fence()

[Greg Kroah-Hartman]

4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>

commit 636deb5b2277cf57bb0f5e00fc9687de9a96061e upstream.

The i915_gem_object_wait_fence() uses an incoming timeout=0 to query
whether the current fence is busy or idle, without waiting. This can be
used by the wait-ioctl to implement a busy query.

Fixes: e95433c73a11 ("drm/i915: Rearrange i915_wait_request() accounting with callers")
Testcase: igt/gem_wait/basic-busy-write-all
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Matthew Auld <matthew.william.auld@xxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: <drm-intel-fixes@xxxxxxxxxxxxxxxxxxxxx> # v4.10-rc1+
Link: http://patchwork.freedesktop.org/patch/msgid/20170212215344.16600-1-chris@xxxxxxxxxxxxxxxxxx
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
(cherry picked from commit d892e9398ecf6defc7972a62227b77dad6be20bd)
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/i915/i915_gem.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -440,7 +440,7 @@ i915_gem_object_wait_reservation(struct
 			timeout = i915_gem_object_wait_fence(shared[i],
 							     flags, timeout,
 							     rps);
-			if (timeout <= 0)
+			if (timeout < 0)
 				break;
 
 			dma_fence_put(shared[i]);
@@ -453,7 +453,7 @@ i915_gem_object_wait_reservation(struct
 		excl = reservation_object_get_excl_rcu(resv);
 	}
 
-	if (excl && timeout > 0)
+	if (excl && timeout >= 0)
 		timeout = i915_gem_object_wait_fence(excl, flags, timeout, rps);
 
 	dma_fence_put(excl);