Re: [PATCH v2 4/4] drm/qxl: use qxl pin function

2020-09-29 Thread Christian König

Am 29.09.20 um 12:53 schrieb Daniel Vetter:

On Tue, Sep 29, 2020 at 11:51:15AM +0200, Gerd Hoffmann wrote:

Otherwise ttm throws a WARN because we try to pin without a reservation.

Fixes: 9d36d4320462 ("drm/qxl: switch over to the new pin interface")
Signed-off-by: Gerd Hoffmann 
---
  drivers/gpu/drm/qxl/qxl_object.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/qxl/qxl_object.c b/drivers/gpu/drm/qxl/qxl_object.c
index d3635e3e3267..eb45267d51db 100644
--- a/drivers/gpu/drm/qxl/qxl_object.c
+++ b/drivers/gpu/drm/qxl/qxl_object.c
@@ -145,7 +145,7 @@ int qxl_bo_create(struct qxl_device *qdev,
return r;
}
if (pinned)
-   ttm_bo_pin(>tbo);
+   qxl_bo_pin(bo);

I think this is now after ttm_bo_init, and at that point the object is
visible to lru users and everything. So I do think you need to grab locks
here instead of just incrementing the pin count alone.

It's also I think a bit racy, since ttm_bo_init drops the lock, so someone
might have snuck in and evicted the object already.

I think what you need is to call ttm_bo_init_reserved, then ttm_bo_pin,
then ttm_bo_unreserve, all explicitly.


Ah, yes Daniel is right. I thought I've fixed that up, but looks like I 
only did that for VMWGFX.


Sorry for the noise, fix to correctly address this is underway.

Regards,
Christian.


-Daniel


*bo_ptr = bo;
return 0;
  }
--
2.27.0



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Re: [PATCH v2 4/4] drm/qxl: use qxl pin function

2020-09-29 Thread Daniel Vetter
On Tue, Sep 29, 2020 at 11:51:15AM +0200, Gerd Hoffmann wrote:
> Otherwise ttm throws a WARN because we try to pin without a reservation.
> 
> Fixes: 9d36d4320462 ("drm/qxl: switch over to the new pin interface")
> Signed-off-by: Gerd Hoffmann 
> ---
>  drivers/gpu/drm/qxl/qxl_object.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/qxl/qxl_object.c 
> b/drivers/gpu/drm/qxl/qxl_object.c
> index d3635e3e3267..eb45267d51db 100644
> --- a/drivers/gpu/drm/qxl/qxl_object.c
> +++ b/drivers/gpu/drm/qxl/qxl_object.c
> @@ -145,7 +145,7 @@ int qxl_bo_create(struct qxl_device *qdev,
>   return r;
>   }
>   if (pinned)
> - ttm_bo_pin(>tbo);
> + qxl_bo_pin(bo);

I think this is now after ttm_bo_init, and at that point the object is
visible to lru users and everything. So I do think you need to grab locks
here instead of just incrementing the pin count alone.

It's also I think a bit racy, since ttm_bo_init drops the lock, so someone
might have snuck in and evicted the object already.

I think what you need is to call ttm_bo_init_reserved, then ttm_bo_pin,
then ttm_bo_unreserve, all explicitly.
-Daniel

>   *bo_ptr = bo;
>   return 0;
>  }
> -- 
> 2.27.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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[PATCH v2 4/4] drm/qxl: use qxl pin function

2020-09-29 Thread Gerd Hoffmann
Otherwise ttm throws a WARN because we try to pin without a reservation.

Fixes: 9d36d4320462 ("drm/qxl: switch over to the new pin interface")
Signed-off-by: Gerd Hoffmann 
---
 drivers/gpu/drm/qxl/qxl_object.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/qxl/qxl_object.c b/drivers/gpu/drm/qxl/qxl_object.c
index d3635e3e3267..eb45267d51db 100644
--- a/drivers/gpu/drm/qxl/qxl_object.c
+++ b/drivers/gpu/drm/qxl/qxl_object.c
@@ -145,7 +145,7 @@ int qxl_bo_create(struct qxl_device *qdev,
return r;
}
if (pinned)
-   ttm_bo_pin(>tbo);
+   qxl_bo_pin(bo);
*bo_ptr = bo;
return 0;
 }
-- 
2.27.0

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