[Intel-gfx] [PATCH 1/2] drm/i915: Use mutex_lock_killable() from inside the shrinker

[Chris Wilson]

If the current process is being killed (it was interrupted with SIGKILL
or equivalent), it will not make any progress in page allocation and we
can abort performing the shrinking on its behalf. So we can use
mutex_lock_killable() instead (although this path should only be
reachable from kswapd currently).

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_shrinker.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 34b108f73f1d..8ad9519779cc 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -39,18 +39,18 @@ static bool shrinker_lock(struct drm_i915_private *i915,
 			  unsigned int flags,
 			  bool *unlock)
 {
-	switch (mutex_trylock_recursive(&i915->drm.struct_mutex)) {
+	struct mutex *m = &i915->drm.struct_mutex;
+
+	switch (mutex_trylock_recursive(m)) {
 	case MUTEX_TRYLOCK_RECURSIVE:
 		*unlock = false;
 		return true;
 
 	case MUTEX_TRYLOCK_FAILED:
 		*unlock = false;
-		if (flags & I915_SHRINK_ACTIVE) {
-			mutex_lock_nested(&i915->drm.struct_mutex,
-					  I915_MM_SHRINKER);
+		if (flags & I915_SHRINK_ACTIVE &&
+		    mutex_lock_killable_nested(m, I915_MM_SHRINKER) == 0)
 			*unlock = true;
-		}
 		return *unlock;
 
 	case MUTEX_TRYLOCK_SUCCESS:
-- 
2.20.1