Reapply "drm/qxl: simplify qxl_fence_wait"

This reverts commit 07ed11afb68d94eadd4ffc082b97c2331307c5ea.

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: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/20240502081641.457aa25f@gandalf.local.home/
Acked-by: Maxime 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: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index 9febc8b73f09efaaaac9d6fb8d2776f2148aed89..368d26da0d6a233467cdc8ef5820ebf4b7ddb964 100644 (file)
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -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))
-                       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.
-        */
+       if (!wait_event_timeout(qdev->release_event,
+                               (dma_fence_is_signaled(fence) ||
+                                (qxl_io_notify_oom(qdev), 0)),
+                               timeout))
+               return 0;
 
-signaled:
        cur = jiffies;
        if (time_after(cur, end))
                return 0;

diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index c3f9bb6602ba2135cae645bda4d730cd703a12a6..e06bad467f55ef1befdad569f0a8a37875def383 100644 (file)
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -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 */