[Intel-gfx] [PATCH] drm/syncobj: Avoid kmalloc(GFP_KERNEL) under spinlock
Maarten Lankhorst
maarten.lankhorst at linux.intel.com
Fri Oct 26 11:49:34 UTC 2018
Op 26-10-18 om 08:20 schreef Chunming Zhou:
> drivers/gpu/drm/drm_syncobj.c:202:4-14: ERROR: function drm_syncobj_find_signal_pt_for_point called on line 390 inside lock on line 389 but uses GFP_KERNEL
>
> Find functions that refer to GFP_KERNEL but are called with locks held.
>
> Generated by: scripts/coccinelle/locks/call_kern.cocci
>
> v2:
> syncobj->timeline still needs protect.
>
> v3:
> use a global signaled fence instead of re-allocation.
>
> v4:
> Don't need moving lock.
> Don't expose func.
>
> v5:
> rename func and directly return.
>
> Tested by: syncobj_wait and ./deqp-vk -n dEQP-VK.*semaphore* with
> lock debug kernel options enabled.
>
> Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: intel-gfx at lists.freedesktop.org
> Cc: Christian König <easy2remember.chk at googlemail.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> CC: Julia Lawall <julia.lawall at lip6.fr>
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
> drivers/gpu/drm/drm_syncobj.c | 36 ++++++++++++++++++-----------------
> 1 file changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index b7eaa603f368..d1c6f21c72b5 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -80,6 +80,23 @@ struct drm_syncobj_signal_pt {
> struct list_head list;
> };
>
> +static DEFINE_SPINLOCK(signaled_fence_lock);
> +static struct dma_fence signaled_fence;
> +
> +static struct dma_fence *drm_syncobj_get_stub_fence(void)
> +{
> + spin_lock(&signaled_fence_lock);
> + if (!signaled_fence.ops) {
> + dma_fence_init(&signaled_fence,
> + &drm_syncobj_stub_fence_ops,
> + &signaled_fence_lock,
> + 0, 0);
> + dma_fence_signal_locked(&signaled_fence);
> + }
> + spin_unlock(&signaled_fence_lock);
Could this be used by drm_syncobj_assign_null_handle too? Maybe as a separate patch?
Reviewed-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
~Maarten
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