From c7faee2109f978f3ef826c48b7e60609061fda4f Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 3 Nov 2016 07:16:43 +0100 Subject: [PATCH] locking/drm: Fix i915_gem_shrinker_lock() locking Mike Krinkin reported hangs in the DRM code and bisected it to: 3ab7c086d5ec72585ef0 ("locking/drm: Kill mutex trickery") Hugh Dickins observed: "i915_gem_shrinker_lock() is broken: but copy the pattern from msm_gem_shrinker_lock() and it's okay - patch below." Pick up the fix in isolation to make sure the bug is fixed, cleanup patch will follow up. Originally-From: Hugh Dickins Reported-by: Hugh Dickins Reported-by: Mike Krinkin Cc: Andrew Morton Cc: Dave Airlie Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: chris@chris-wilson.co.uk Cc: jason.low2@hpe.com Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1610301645180.28429@eggly.anvils Signed-off-by: Ingo Molnar --- drivers/gpu/drm/i915/i915_gem_shrinker.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c index 36953757687e..e9bd2a81d03a 100644 --- a/drivers/gpu/drm/i915/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c @@ -228,8 +228,9 @@ unsigned long i915_gem_shrink_all(struct drm_i915_private *dev_priv) static bool i915_gem_shrinker_lock(struct drm_device *dev, bool *unlock) { if (!mutex_trylock(&dev->struct_mutex)) - *unlock = false; + return false; + *unlock = true; return true; } -- 2.20.1