drm/i915: Pass timeout==0 on to i915_gem_object_wait_fence()

BugLink: http://bugs.launchpad.net/bugs/1673118
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@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.10-rc1+
Link: http://patchwork.freedesktop.org/patch/msgid/20170212215344.16600-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
(cherry picked from commit d892e9398ecf6defc7972a62227b77dad6be20bd)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 24b5b046754b37e8b8e3ab2c04a9f890b41eecf9..7f4a54b94447b9ac4686e5011d5b860c11532a8a 100644 (file)
--- 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 reservation_object *resv,
                        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 reservation_object *resv,
                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);