From 789bb43f1a9951a85bcc48aecd3a026c13ab5170 Mon Sep 17 00:00:00 2001 From: Nirmoy Das Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] drm/xe/ufence: Wake up waiters after setting ufence->signalled MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit BugLink: https://bugs.launchpad.net/bugs/2101915 [ Upstream commit 37a1cf288e4538eb39b38dbc745fe0da7ae53d94 ] If a previous ufence is not signalled, vm_bind will return -EBUSY. Delaying the modification of ufence->signalled can cause issues if the UMD reuses the same ufence so update ufence->signalled before waking up waiters. Cc: Matthew Brost Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/3233 Fixes: 977e5b82e090 ("drm/xe: Expose user fence from xe_sync_entry") Reviewed-by: Matthew Brost Link: https://patchwork.freedesktop.org/patch/msgid/20241114150537.4161573-1-nirmoy.das@intel.com Signed-off-by: Nirmoy Das (cherry picked from commit 553a5d14fcd927194c409b10faced6a6dbc678d1) Signed-off-by: Thomas Hellström Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/gpu/drm/xe/xe_sync.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/xe/xe_sync.c b/drivers/gpu/drm/xe/xe_sync.c index 7f903084f0f7..d38f9de90184 100644 --- a/drivers/gpu/drm/xe/xe_sync.c +++ b/drivers/gpu/drm/xe/xe_sync.c @@ -80,8 +80,12 @@ static void user_fence_worker(struct work_struct *w) mmput(ufence->mm); } - wake_up_all(&ufence->xe->ufence_wq); + /* + * Wake up waiters only after updating the ufence state, allowing the UMD + * to safely reuse the same ufence without encountering -EBUSY errors. + */ WRITE_ONCE(ufence->signalled, 1); + wake_up_all(&ufence->xe->ufence_wq); user_fence_put(ufence); }