Messages in this thread | | | Subject | Re: [PATCH] dma-fence: add might_sleep annotation to _wait() | From | Christian König <> | Date | Wed, 20 May 2020 08:54:36 +0200 |
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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 <alexander.deucher@amd.com> > Cc: Lucas Stach <l.stach@pengutronix.de> > Cc: Jani Nikula <jani.nikula@linux.intel.com> > Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> > Cc: Ben Skeggs <bskeggs@redhat.com> > Cc: "VMware Graphics" <linux-graphics-maintainer@vmware.com> > Cc: Oded Gabbay <oded.gabbay@gmail.com> > Cc: linux-media@vger.kernel.org > Cc: linaro-mm-sig@lists.linaro.org > Cc: linux-rdma@vger.kernel.org > Cc: amd-gfx@lists.freedesktop.org > Cc: intel-gfx@lists.freedesktop.org > Cc: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> > Cc: Christian König <christian.koenig@amd.com> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
> --- > 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);
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