| Message ID | 20191015011438.22184-1-dave@stgolabs.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/msm/a5xx: Fix barrier usage in set_preempt_state() | expand |
Forgot to Cc lkml. On Mon, 14 Oct 2019, Davidlohr Bueso wrote: >Because it is not a Rmw operation, atomic_set() is never serialized, >and therefore the 'upgradable' smp_mb__{before,after}_atomic() calls >that order the write to preempt_state are completely bogus. > >This patch replaces these with smp_mb(), which seems like the >original intent of when the code was written. > >Signed-off-by: Davidlohr Bueso <dbueso@suse.de> >--- > drivers/gpu/drm/msm/adreno/a5xx_preempt.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > >diff --git a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c >index 9cf9353a7ff1..d27d8d3208c6 100644 >--- a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c >+++ b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c >@@ -30,10 +30,10 @@ static inline void set_preempt_state(struct a5xx_gpu *gpu, > * preemption or in the interrupt handler so barriers are needed > * before... > */ >- smp_mb__before_atomic(); >+ smp_mb(); > atomic_set(&gpu->preempt_state, new); > /* ... and after*/ >- smp_mb__after_atomic(); >+ smp_mb(); > } > > /* Write the most recent wptr for the given ring into the hardware */ >-- >2.16.4 >
diff --git a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c index 9cf9353a7ff1..d27d8d3208c6 100644 --- a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c +++ b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c @@ -30,10 +30,10 @@ static inline void set_preempt_state(struct a5xx_gpu *gpu, * preemption or in the interrupt handler so barriers are needed * before... */ - smp_mb__before_atomic(); + smp_mb(); atomic_set(&gpu->preempt_state, new); /* ... and after*/ - smp_mb__after_atomic(); + smp_mb(); } /* Write the most recent wptr for the given ring into the hardware */
Because it is not a Rmw operation, atomic_set() is never serialized, and therefore the 'upgradable' smp_mb__{before,after}_atomic() calls that order the write to preempt_state are completely bogus. This patch replaces these with smp_mb(), which seems like the original intent of when the code was written. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> --- drivers/gpu/drm/msm/adreno/a5xx_preempt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)