diff options
| author | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-08-15 10:41:47 +0200 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2016-08-15 10:41:47 +0200 |
| commit | cc9263874b42bf98209dce0afe698b550648e770 (patch) | |
| tree | f0eafd344c501e420de06c2e0f29f2ae0e6a9a1b /include/linux/percpu-refcount.h | |
| parent | 02bef8f98d26e9774b49c78a42b29b168e8876fc (diff) | |
| parent | fc93ff608b15ae32cde3006b7af860b59cac20ec (diff) | |
Merge remote-tracking branch 'airlied/drm-next' into drm-intel-next-queued
Backmerge because too many conflicts, and also we need to get at the
latest struct fence patches from Gustavo. Requested by Chris Wilson.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Diffstat (limited to 'include/linux/percpu-refcount.h')
| -rw-r--r-- | include/linux/percpu-refcount.h | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index 84f542df7ff5..1c7eec09e5eb 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -136,14 +136,12 @@ static inline bool __ref_is_percpu(struct percpu_ref *ref, * used as a pointer. If the compiler generates a separate fetch * when using it as a pointer, __PERCPU_REF_ATOMIC may be set in * between contaminating the pointer value, meaning that - * ACCESS_ONCE() is required when fetching it. - * - * Also, we need a data dependency barrier to be paired with - * smp_store_release() in __percpu_ref_switch_to_percpu(). - * - * Use lockless deref which contains both. + * READ_ONCE() is required when fetching it. */ - percpu_ptr = lockless_dereference(ref->percpu_count_ptr); + percpu_ptr = READ_ONCE(ref->percpu_count_ptr); + + /* paired with smp_store_release() in __percpu_ref_switch_to_percpu() */ + smp_read_barrier_depends(); /* * Theoretically, the following could test just ATOMIC; however, |