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