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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2016-08-05 10:14:19 +0100 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2016-08-05 10:54:41 +0100 |
| commit | c21724cc4d3d5c96a15347f2435a753aff2007c4 (patch) | |
| tree | 7e8995fb3cde407e8b3d7dac7a88a3c07f9906d4 | |
| parent | 3fdc13c7a3cbd5788daad4cf1ddc619856e2f1c0 (diff) | |
| download | linux-stable-c21724cc4d3d5c96a15347f2435a753aff2007c4.tar.gz linux-stable-c21724cc4d3d5c96a15347f2435a753aff2007c4.tar.bz2 linux-stable-c21724cc4d3d5c96a15347f2435a753aff2007c4.zip | |
drm/i915: Reduce locking inside swfinish ioctl
We only need to take the struct_mutex if the object is pinned to the
display engine and so requires checking for clflush. (The race with
userspace pinning the object to a framebuffer is irrelevant.)
v2: Use access once for compiler hints (or not as it is a bitfield)
v3: READ_ONCE, obj->pin_display is not a bitfield anymore
v4: Don't be creative with goto.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470388464-28458-14-git-send-email-chris@chris-wilson.co.uk
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem.c | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 1d8858d7973d..03e806ce75ea 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1518,26 +1518,23 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data, { struct drm_i915_gem_sw_finish *args = data; struct drm_i915_gem_object *obj; - int ret = 0; - - ret = i915_mutex_lock_interruptible(dev); - if (ret) - return ret; + int err = 0; obj = i915_gem_object_lookup(file, args->handle); - if (!obj) { - ret = -ENOENT; - goto unlock; - } + if (!obj) + return -ENOENT; /* Pinned buffers may be scanout, so flush the cache */ - if (obj->pin_display) - i915_gem_object_flush_cpu_write_domain(obj); + if (READ_ONCE(obj->pin_display)) { + err = i915_mutex_lock_interruptible(dev); + if (!err) { + i915_gem_object_flush_cpu_write_domain(obj); + mutex_unlock(&dev->struct_mutex); + } + } - i915_gem_object_put(obj); -unlock: - mutex_unlock(&dev->struct_mutex); - return ret; + i915_gem_object_put_unlocked(obj); + return err; } /** |