[PATCH 6.6 027/122] Revert "drm/qxl: simplify qxl_fence_wait"

Greg Kroah-Hartman
2024-04-15T14:33:30Z

From: Alex Constantino <dreaming.about.electric.sheep@gmail.com>

[ Upstream commit 07ed11afb68d94eadd4ffc082b97c2331307c5ea ]

This reverts commit 5a838e5d5825c85556011478abde708251cc0776.

Changes from commit 5a838e5d5825 ("drm/qxl: simplify qxl_fence_wait") would
result in a '[TTM] Buffer eviction failed' exception whenever it reached a
timeout.
Due to a dependency to DMA_FENCE_WARN this also restores some code deleted
by commit d72277b6c37d ("dma-buf: nuke DMA_FENCE_TRACE macros v2").

Fixes: 5a838e5d5825 ("drm/qxl: simplify qxl_fence_wait")
Link: https://lore.kernel.org/regressions/ZTgydqRlK6WX_b29@eldamar.lan/
Reported-by: Timo Lindfors <timo.lindfors@iki.fi>
Closes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1054514
Signed-off-by: Alex Constantino <dreaming.about.electric.sheep@gmail.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240404181448.1643-2-dreaming.about.electric.sheep@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/qxl/qxl_release.c | 50 +++++++++++++++++++++++++++----
include/linux/dma-fence.h | 7 +++++
2 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index 368d26da0d6a2..9febc8b73f09e 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -58,16 +58,56 @@ 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;

- if (!wait_event_timeout(qdev->release_event,
- (dma_fence_is_signaled(fence) ||
- (qxl_io_notify_oom(qdev), 0)),
- timeout))
- return 0;
+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.
+ */

+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 b3772edca2e6e..fd4a823ce3cdb 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -681,4 +681,11 @@ 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 */
--
2.43.0