Do it uncontionally, there's a separate peek function with
dma_fence_is_signalled() which can be called from atomic context.
v2: Consensus calls for an unconditional might_sleep (Chris,
Christian)
Full audit:
- dma-fence.h: Uses MAX_SCHEDULE_TIMOUT, good chance this sleeps
- dma-resv.c: Timeout always at least 1
- st-dma-fence.c: Save to sleep in testcases
- amdgpu_cs.c: Both callers are for variants of the wait ioctl
- amdgpu_device.c: Two callers in vram recover code, both right next
to mutex_lock.
- amdgpu_vm.c: Use in the vm_wait ioctl, next to _reserve/unreserve
- remaining functions in amdgpu: All for test_ib implementations for
various engines, caller for that looks all safe (debugfs, driver
load, reset)
- etnaviv: another wait ioctl
- habanalabs: another wait ioctl
- nouveau_fence.c: hardcoded 15*HZ ... glorious
- nouveau_gem.c: hardcoded 2*HZ ... so not even super consistent, but
this one does have a WARN_ON :-/ At least this one is only a
fallback path for when kmalloc fails. Maybe this should be put onto
some worker list instead, instead of a work per unamp ...
- i915/selftests: Hardecoded HZ / 4 or HZ / 8
- i915/gt/selftests: Going up the callchain looks safe looking at
nearby callers
- i915/gt/intel_gt_requests.c. Wrapped in a mutex_lock
- i915/gem_i915_gem_wait.c: The i915-version which is called instead
for i915 fences already has a might_sleep() annotation, so all good
Cc: Alex Deucher <[email protected]>
Cc: Lucas Stach <[email protected]>
Cc: Jani Nikula <[email protected]>
Cc: Joonas Lahtinen <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Ben Skeggs <[email protected]>
Cc: "VMware Graphics" <[email protected]>
Cc: Oded Gabbay <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Chris Wilson <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Christian König <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
---
drivers/dma-buf/dma-fence.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 90edf2b281b0..656e9ac2d028 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -208,6 +208,8 @@ dma_fence_wait_timeout(struct dma_fence *fence, bool intr, signed long timeout)
if (WARN_ON(timeout < 0))
return -EINVAL;
+ might_sleep();
+
trace_dma_fence_wait_start(fence);
if (fence->ops->wait)
ret = fence->ops->wait(fence, intr, timeout);
--
2.26.2
Am 19.05.20 um 15:27 schrieb Daniel Vetter:
> Do it uncontionally, there's a separate peek function with
> dma_fence_is_signalled() which can be called from atomic context.
>
> v2: Consensus calls for an unconditional might_sleep (Chris,
> Christian)
>
> Full audit:
> - dma-fence.h: Uses MAX_SCHEDULE_TIMOUT, good chance this sleeps
> - dma-resv.c: Timeout always at least 1
> - st-dma-fence.c: Save to sleep in testcases
> - amdgpu_cs.c: Both callers are for variants of the wait ioctl
> - amdgpu_device.c: Two callers in vram recover code, both right next
> to mutex_lock.
> - amdgpu_vm.c: Use in the vm_wait ioctl, next to _reserve/unreserve
> - remaining functions in amdgpu: All for test_ib implementations for
> various engines, caller for that looks all safe (debugfs, driver
> load, reset)
> - etnaviv: another wait ioctl
> - habanalabs: another wait ioctl
> - nouveau_fence.c: hardcoded 15*HZ ... glorious
> - nouveau_gem.c: hardcoded 2*HZ ... so not even super consistent, but
> this one does have a WARN_ON :-/ At least this one is only a
> fallback path for when kmalloc fails. Maybe this should be put onto
> some worker list instead, instead of a work per unamp ...
> - i915/selftests: Hardecoded HZ / 4 or HZ / 8
> - i915/gt/selftests: Going up the callchain looks safe looking at
> nearby callers
> - i915/gt/intel_gt_requests.c. Wrapped in a mutex_lock
> - i915/gem_i915_gem_wait.c: The i915-version which is called instead
> for i915 fences already has a might_sleep() annotation, so all good
>
> Cc: Alex Deucher <[email protected]>
> Cc: Lucas Stach <[email protected]>
> Cc: Jani Nikula <[email protected]>
> Cc: Joonas Lahtinen <[email protected]>
> Cc: Rodrigo Vivi <[email protected]>
> Cc: Ben Skeggs <[email protected]>
> Cc: "VMware Graphics" <[email protected]>
> Cc: Oded Gabbay <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Cc: Chris Wilson <[email protected]>
> Cc: Maarten Lankhorst <[email protected]>
> Cc: Christian König <[email protected]>
> Signed-off-by: Daniel Vetter <[email protected]>
Reviewed-by: Christian König <[email protected]>
> ---
> drivers/dma-buf/dma-fence.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> index 90edf2b281b0..656e9ac2d028 100644
> --- a/drivers/dma-buf/dma-fence.c
> +++ b/drivers/dma-buf/dma-fence.c
> @@ -208,6 +208,8 @@ dma_fence_wait_timeout(struct dma_fence *fence, bool intr, signed long timeout)
> if (WARN_ON(timeout < 0))
> return -EINVAL;
>
> + might_sleep();
> +
> trace_dma_fence_wait_start(fence);
> if (fence->ops->wait)
> ret = fence->ops->wait(fence, intr, timeout);
On Wed, May 20, 2020 at 08:54:36AM +0200, Christian K?nig wrote:
> Am 19.05.20 um 15:27 schrieb Daniel Vetter:
> > Do it uncontionally, there's a separate peek function with
> > dma_fence_is_signalled() which can be called from atomic context.
> >
> > v2: Consensus calls for an unconditional might_sleep (Chris,
> > Christian)
> >
> > Full audit:
> > - dma-fence.h: Uses MAX_SCHEDULE_TIMOUT, good chance this sleeps
> > - dma-resv.c: Timeout always at least 1
> > - st-dma-fence.c: Save to sleep in testcases
> > - amdgpu_cs.c: Both callers are for variants of the wait ioctl
> > - amdgpu_device.c: Two callers in vram recover code, both right next
> > to mutex_lock.
> > - amdgpu_vm.c: Use in the vm_wait ioctl, next to _reserve/unreserve
> > - remaining functions in amdgpu: All for test_ib implementations for
> > various engines, caller for that looks all safe (debugfs, driver
> > load, reset)
> > - etnaviv: another wait ioctl
> > - habanalabs: another wait ioctl
> > - nouveau_fence.c: hardcoded 15*HZ ... glorious
> > - nouveau_gem.c: hardcoded 2*HZ ... so not even super consistent, but
> > this one does have a WARN_ON :-/ At least this one is only a
> > fallback path for when kmalloc fails. Maybe this should be put onto
> > some worker list instead, instead of a work per unamp ...
> > - i915/selftests: Hardecoded HZ / 4 or HZ / 8
> > - i915/gt/selftests: Going up the callchain looks safe looking at
> > nearby callers
> > - i915/gt/intel_gt_requests.c. Wrapped in a mutex_lock
> > - i915/gem_i915_gem_wait.c: The i915-version which is called instead
> > for i915 fences already has a might_sleep() annotation, so all good
> >
> > Cc: Alex Deucher <[email protected]>
> > Cc: Lucas Stach <[email protected]>
> > Cc: Jani Nikula <[email protected]>
> > Cc: Joonas Lahtinen <[email protected]>
> > Cc: Rodrigo Vivi <[email protected]>
> > Cc: Ben Skeggs <[email protected]>
> > Cc: "VMware Graphics" <[email protected]>
> > Cc: Oded Gabbay <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: Chris Wilson <[email protected]>
> > Cc: Maarten Lankhorst <[email protected]>
> > Cc: Christian K?nig <[email protected]>
> > Signed-off-by: Daniel Vetter <[email protected]>
>
> Reviewed-by: Christian K?nig <[email protected]>
intel-gfx-ci approves too, thanks to both of you for reviews, patch merged
to drm-misc-next.
-Daniel
>
> > ---
> > drivers/dma-buf/dma-fence.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> > index 90edf2b281b0..656e9ac2d028 100644
> > --- a/drivers/dma-buf/dma-fence.c
> > +++ b/drivers/dma-buf/dma-fence.c
> > @@ -208,6 +208,8 @@ dma_fence_wait_timeout(struct dma_fence *fence, bool intr, signed long timeout)
> > if (WARN_ON(timeout < 0))
> > return -EINVAL;
> > + might_sleep();
> > +
> > trace_dma_fence_wait_start(fence);
> > if (fence->ops->wait)
> > ret = fence->ops->wait(fence, intr, timeout);
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch