* [PATCH 1/5] drm/msm: Fix improper uses of smp_mb__{before,after}_atomic()
2019-04-29 20:14 ` [PATCH 1/5] drm/msm: Fix improper uses of smp_mb__{before,after}_atomic() Andrea Parri
@ 2019-04-29 20:14 ` Andrea Parri
2019-05-09 20:19 ` Andrea Parri
1 sibling, 0 replies; 3+ messages in thread
From: Andrea Parri @ 2019-04-29 20:14 UTC (permalink / raw)
To: linux-kernel
Cc: Andrea Parri, stable, Rob Clark, Sean Paul, David Airlie,
Daniel Vetter, Jordan Crouse, linux-arm-msm, dri-devel, freedreno
These barriers only apply to the read-modify-write operations; in
particular, they do not apply to the atomic_set() primitive.
Replace the barriers with smp_mb()s.
Fixes: b1fc2839d2f92 ("drm/msm: Implement preemption for A5XX targets")
Cc: stable@vger.kernel.org
Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Jordan Crouse <jcrouse@codeaurora.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: freedreno@lists.freedesktop.org
---
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 3d62310a535fb..ee0820ee0c664 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
@@ -39,10 +39,10 @@ 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 */
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH 1/5] drm/msm: Fix improper uses of smp_mb__{before,after}_atomic()
2019-04-29 20:14 ` [PATCH 1/5] drm/msm: Fix improper uses of smp_mb__{before,after}_atomic() Andrea Parri
2019-04-29 20:14 ` Andrea Parri
@ 2019-05-09 20:19 ` Andrea Parri
1 sibling, 0 replies; 3+ messages in thread
From: Andrea Parri @ 2019-05-09 20:19 UTC (permalink / raw)
To: linux-kernel
Cc: Rob Clark, Sean Paul, David Airlie, Daniel Vetter, Jordan Crouse,
linux-arm-msm, dri-devel, freedreno, Paul E. McKenney,
Peter Zijlstra
On Mon, Apr 29, 2019 at 10:14:57PM +0200, Andrea Parri wrote:
> These barriers only apply to the read-modify-write operations; in
> particular, they do not apply to the atomic_set() primitive.
>
> Replace the barriers with smp_mb()s.
>
> Fixes: b1fc2839d2f92 ("drm/msm: Implement preemption for A5XX targets")
> Cc: stable@vger.kernel.org
> Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com>
> Reported-by: Peter Zijlstra <peterz@infradead.org>
> Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: Sean Paul <sean@poorly.run>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Jordan Crouse <jcrouse@codeaurora.org>
> Cc: linux-arm-msm@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: freedreno@lists.freedesktop.org
Rob, Sean, Jordan: any suggestions to move this patch forward?
Thanx,
Andrea
> ---
> 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 3d62310a535fb..ee0820ee0c664 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
> @@ -39,10 +39,10 @@ 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 */
> --
> 2.7.4
>
^ permalink raw reply [flat|nested] 3+ messages in thread