From 37a1cf288e4538eb39b38dbc745fe0da7ae53d94 Mon Sep 17 00:00:00 2001 From: Nirmoy Das Date: Thu, 14 Nov 2024 16:05:37 +0100 Subject: [PATCH] drm/xe/ufence: Wake up waiters after setting ufence->signalled MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 --- 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 a90480c6aecf..42f5bebd09e5 100644 --- a/drivers/gpu/drm/xe/xe_sync.c +++ b/drivers/gpu/drm/xe/xe_sync.c @@ -87,8 +87,12 @@ static void user_fence_worker(struct work_struct *w) drm_dbg(&ufence->xe->drm, "mmget_not_zero() failed, ufence wasn't signaled\n"); } - 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); } -- 2.20.1