locking fixes
Subsystems (3)
Linus,
Please pull the latest locking-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-urgent-for-linus
# HEAD: 112dc0c8069e5554e0ad29c58228f1e6ca49e13d locking/barriers: Suppress sparse warnings in lockless_dereference()
Two lockless_dereference() related fixes.
Thanks,
Ingo
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Johannes Berg (2):
Revert "drm/fb-helper: Reduce READ_ONCE(master) to lockless_dereference" locking/barriers: Suppress sparse warnings in lockless_dereference()
drivers/gpu/drm/drm_fb_helper.c | 2 +- include/linux/compiler.h | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-)
drivers/gpu/drm/drm_fb_helper.c +1 -1
@@ -464,7 +464,7 @@ static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper)/* Sometimes user space wants everything disabled, so don't steal the * display if there's a master. */ -if (lockless_dereference (dev->master)) +if (READ_ONCE (dev->master))return false;drm_for_each_crtc (crtc, dev) {
include/linux/compiler.h +3 -3
@@ -527,13 +527,13 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s* object's lifetime is managed by something other than RCU. That * "something other" might be reference counting or simple immortality. * -* The seemingly unused void * variable is to validate @p is indeed a pointer -* type. All pointer types silently cast to void *. +* The seemingly unused size_t variable is to validate @p is indeed a pointer +* type by making sure it can be dereferenced. */ #define lockless_dereference (p) \ ({ \ typeof(p) _________p1 = READ_ONCE(p); \ - __maybe_unused const void * const _________p2 = _________p1; \ + size_t __maybe_unused __size_of_ptr = sizeof(*(p)); \ smp_read_barrier_depends();/* Dependency order vs. p above. */ \ (_________p1); \ })