Commit 3628e038 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Reapply "drm/qxl: simplify qxl_fence_wait" 



This reverts commit 07ed11af.

Stephen Rostedt reports:
 "I went to run my tests on my VMs and the tests hung on boot up.
  Unfortunately, the most I ever got out was:

  [   93.607888] Testing event system initcall: OK
  [   93.667730] Running tests on all trace events:
  [   93.669757] Testing all events: OK
  [   95.631064] ------------[ cut here ]------------
  Timed out after 60 seconds"

and further debugging points to a possible circular locking dependency
between the console_owner locking and the worker pool locking.

Reverting the commit allows Steve's VM to boot to completion again.

[ This may obviously result in the "[TTM] Buffer eviction failed"
  messages again, which was the reason for that original revert. But at
  this point this seems preferable to a non-booting system... ]

Reported-and-bisected-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/20240502081641.457aa25f@gandalf.local.home/


Acked-by: default avatarMaxime Ripard <mripard@kernel.org>
Cc: Alex Constantino <dreaming.about.electric.sheep@gmail.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Timo Lindfors <timo.lindfors@iki.fi>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ee5b455b

drivers/gpu/drm/qxl/qxl_release.c

+5 −45
Original line number Diff line number Diff line
@@ -58,56 +58,16 @@ static long qxl_fence_wait(struct dma_fence *fence, bool intr, 
			   signed long timeout)

{

	struct qxl_device *qdev;

	struct qxl_release *release;

	int count = 0, sc = 0;

	bool have_drawable_releases;

	unsigned long cur, end = jiffies + timeout;



	qdev = container_of(fence->lock, struct qxl_device, release_lock);

	release = container_of(fence, struct qxl_release, base);

	have_drawable_releases = release->type == QXL_RELEASE_DRAWABLE;



retry:

	sc++;



	if (dma_fence_is_signaled(fence))

		goto signaled;



	qxl_io_notify_oom(qdev);



	for (count = 0; count < 11; count++) {

		if (!qxl_queue_garbage_collect(qdev, true))

			break;



		if (dma_fence_is_signaled(fence))

			goto signaled;

	}



	if (dma_fence_is_signaled(fence))

		goto signaled;



	if (have_drawable_releases || sc < 4) {

		if (sc > 2)

			/* back off */

			usleep_range(500, 1000);



		if (time_after(jiffies, end))

	if (!wait_event_timeout(qdev->release_event,

				(dma_fence_is_signaled(fence) ||

				 (qxl_io_notify_oom(qdev), 0)),

				timeout))

		return 0;



		if (have_drawable_releases && sc > 300) {

			DMA_FENCE_WARN(fence,

				       "failed to wait on release %llu after spincount %d\n",

				       fence->context & ~0xf0000000, sc);

			goto signaled;

		}

		goto retry;

	}

	/*

	 * yeah, original sync_obj_wait gave up after 3 spins when

	 * have_drawable_releases is not set.

	 */



signaled:

	cur = jiffies;

	if (time_after(cur, end))

		return 0;

include/linux/dma-fence.h

+0 −7
Original line number Diff line number Diff line
@@ -682,11 +682,4 @@ static inline bool dma_fence_is_container(struct dma_fence *fence) 
	return dma_fence_is_array(fence) || dma_fence_is_chain(fence);

}



#define DMA_FENCE_WARN(f, fmt, args...) \

	do {								\

		struct dma_fence *__ff = (f);				\

		pr_warn("f %llu#%llu: " fmt, __ff->context, __ff->seqno,\

			 ##args);					\

	} while (0)



#endif /* __LINUX_DMA_FENCE_H */