2015-11-12 07:10:04

by Alexandre Courbot

Subject: [PATCH] drm/tegra: fix locking of SET_TILING ioctl

drm_gem_object_unreference() now expects obj->dev->struct_mutex to be
held. Use the newly-introduced drm_gem_object_unreference_unlocked()
which handles locking for us.

If we don't do this drm_gem_object_unreference() will get noisy about
struct_mutex not being held every time we call the SET_TILING ioctl.

Signed-off-by: Alexandre Courbot <[email protected]>
---
drivers/gpu/drm/tegra/drm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index cc48334ef164..c0ae89865958 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -683,7 +683,7 @@ static int tegra_gem_set_tiling(struct drm_device *drm, void *data,
bo->tiling.mode = mode;
bo->tiling.value = value;

- drm_gem_object_unreference(gem);
+ drm_gem_object_unreference_unlocked(gem);

return 0;
}
--
2.6.2

2015-11-17 10:02:49

by Daniel Vetter

Subject: Re: [PATCH] drm/tegra: fix locking of SET_TILING ioctl

On Thu, Nov 12, 2015 at 04:09:56PM +0900, Alexandre Courbot wrote:
> drm_gem_object_unreference() now expects obj->dev->struct_mutex to be
> held. Use the newly-introduced drm_gem_object_unreference_unlocked()
> which handles locking for us.

This rule has been really old, I simply made the checking more anal in

commit ef4c6270bf2867e2f8032e9614d1a8cfc6c71663
Author: Daniel Vetter <[email protected]>
Date: Thu Oct 15 09:36:25 2015 +0200

drm/gem: Check locking in drm_gem_object_unreference

With the above added this is:

Reviewed-by: Daniel Vetter <[email protected]>

>
> If we don't do this drm_gem_object_unreference() will get noisy about
> struct_mutex not being held every time we call the SET_TILING ioctl.
>
> Signed-off-by: Alexandre Courbot <[email protected]>
> ---
> drivers/gpu/drm/tegra/drm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> index cc48334ef164..c0ae89865958 100644
> --- a/drivers/gpu/drm/tegra/drm.c
> +++ b/drivers/gpu/drm/tegra/drm.c
> @@ -683,7 +683,7 @@ static int tegra_gem_set_tiling(struct drm_device *drm, void *data,
> bo->tiling.mode = mode;
> bo->tiling.value = value;
>
> - drm_gem_object_unreference(gem);
> + drm_gem_object_unreference_unlocked(gem);
>
> return 0;
> }
> --
> 2.6.2
>
> _______________________________________________
> dri-devel mailing list
> [email protected]
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

2015-11-19 04:52:25

by Alexandre Courbot

Subject: Re: [PATCH] drm/tegra: fix locking of SET_TILING ioctl

On Tue, Nov 17, 2015 at 7:02 PM, Daniel Vetter <[email protected]> wrote:
> On Thu, Nov 12, 2015 at 04:09:56PM +0900, Alexandre Courbot wrote:
>> drm_gem_object_unreference() now expects obj->dev->struct_mutex to be
>> held. Use the newly-introduced drm_gem_object_unreference_unlocked()
>> which handles locking for us.
>
> This rule has been really old, I simply made the checking more anal in
>
> commit ef4c6270bf2867e2f8032e9614d1a8cfc6c71663
> Author: Daniel Vetter <[email protected]>
> Date: Thu Oct 15 09:36:25 2015 +0200
>
> drm/gem: Check locking in drm_gem_object_unreference
>
> With the above added this is:
>
> Reviewed-by: Daniel Vetter <[email protected]

Thanks! Sending an updated version.