[PATCH] drm/radeon: hold reference to fences in radeon_sa_bo_new (3.17 and older)

[Luis Henriques]

On Tue, Mar 15, 2016 at 12:56:45PM -0500, Nicolai Hähnle wrote:
> From: Nicolai Hähnle 
> 
> [Backport of upstream commit f6ff4f67cdf8455d0a4226eeeaf5af17c37d05eb, with
>  an additional NULL pointer guard that is required for kernels 3.17 and older.
>

Thank you, Nicolai.  I'll queue this backport for the 3.16.

Cheers,
--
Luís


>  To be precise, any kernel that does *not* have commit 954605ca3 "drm/radeon:
>  use common fence implementation for fences, v4" requires this additional
>  NULL pointer guard.]
> 
> An arbitrary amount of time can pass between spin_unlock and
> radeon_fence_wait_any, so we need to ensure that nobody frees the
> fences from under us.
> 
> Based on the analogous fix for amdgpu.
> 
> Signed-off-by: Nicolai Hähnle 
> Reviewed-by: Christian König  (v1 + fix)
> Tested-by: Lutz Euler 
> Cc: stable at vger.kernel.org
> ---
>  drivers/gpu/drm/radeon/radeon_sa.c | 7 +++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon_sa.c 
> b/drivers/gpu/drm/radeon/radeon_sa.c
> index c507896..7d11901 100644
> --- a/drivers/gpu/drm/radeon/radeon_sa.c
> +++ b/drivers/gpu/drm/radeon/radeon_sa.c
> @@ -349,8 +349,15 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
>   /* see if we can skip over some allocations */
>   } while (radeon_sa_bo_next_hole(sa_manager, fences, tries));
>  
> + for (i = 0; i < RADEON_NUM_RINGS; ++i) {
> + if (fences[i])
> + radeon_fence_ref(fences[i]);
> + }
> +
>   spin_unlock(_manager->wq.lock);
>   r = radeon_fence_wait_any(rdev, fences, false);
> + for (i = 0; i < RADEON_NUM_RINGS; ++i)
> + radeon_fence_unref([i]);
>   spin_lock(_manager->wq.lock);
>   /* if we have nothing to wait for block */
>   if (r == -ENOENT) {
> -- 
> 2.5.0
> 
> --
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[PATCH] drm/radeon: hold reference to fences in radeon_sa_bo_new (3.17 and older)

[Nicolai Hähnle]

From: Nicolai Hähnle 

[Backport of upstream commit f6ff4f67cdf8455d0a4226eeeaf5af17c37d05eb, with
 an additional NULL pointer guard that is required for kernels 3.17 and older.

 To be precise, any kernel that does *not* have commit 954605ca3 "drm/radeon:
 use common fence implementation for fences, v4" requires this additional
 NULL pointer guard.]

An arbitrary amount of time can pass between spin_unlock and
radeon_fence_wait_any, so we need to ensure that nobody frees the
fences from under us.

Based on the analogous fix for amdgpu.

Signed-off-by: Nicolai Hähnle 
Reviewed-by: Christian König  (v1 + fix)
Tested-by: Lutz Euler 
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/radeon/radeon_sa.c | 7 +++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_sa.c 
b/drivers/gpu/drm/radeon/radeon_sa.c
index c507896..7d11901 100644
--- a/drivers/gpu/drm/radeon/radeon_sa.c
+++ b/drivers/gpu/drm/radeon/radeon_sa.c
@@ -349,8 +349,15 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
/* see if we can skip over some allocations */
} while (radeon_sa_bo_next_hole(sa_manager, fences, tries));

+   for (i = 0; i < RADEON_NUM_RINGS; ++i) {
+   if (fences[i])
+   radeon_fence_ref(fences[i]);
+   }
+
spin_unlock(_manager->wq.lock);
r = radeon_fence_wait_any(rdev, fences, false);
+   for (i = 0; i < RADEON_NUM_RINGS; ++i)
+   radeon_fence_unref([i]);
spin_lock(_manager->wq.lock);
/* if we have nothing to wait for block */
if (r == -ENOENT) {
-- 
2.5.0