Patch "drm/xe: Use ordered WQ for G2H handler" has been added to the 6.8-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/xe: Use ordered WQ for G2H handler

to the 6.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-xe-use-ordered-wq-for-g2h-handler.patch
and it can be found in the queue-6.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 95ad221bf81e254480d050b9df5fda71170189cc
Author: Matthew Brost <matthew.brost@xxxxxxxxx>
Date:   Sun May 5 20:47:58 2024 -0700

    drm/xe: Use ordered WQ for G2H handler
    
    [ Upstream commit c002bfe644a29ba600c571f2abba13a155a12dcd ]
    
    System work queues are shared, use a dedicated work queue for G2H
    processing to avoid G2H processing getting block behind system tasks.
    
    Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
    Cc: <stable@xxxxxxxxxxxxxxx>
    Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
    Reviewed-by: Francois Dugast <francois.dugast@xxxxxxxxx>
    Link: https://patchwork.freedesktop.org/patch/msgid/20240506034758.3697397-1-matthew.brost@xxxxxxxxx
    (cherry picked from commit 50aec9665e0babd62b9eee4e613d9a1ef8d2b7de)
    Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
index 006c6830b55a7..917082af197cd 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct.c
+++ b/drivers/gpu/drm/xe/xe_guc_ct.c
@@ -113,6 +113,7 @@ static void guc_ct_fini(struct drm_device *drm, void *arg)
 {
 	struct xe_guc_ct *ct = arg;
 
+	destroy_workqueue(ct->g2h_wq);
 	xa_destroy(&ct->fence_lookup);
 }
 
@@ -138,6 +139,10 @@ int xe_guc_ct_init(struct xe_guc_ct *ct)
 
 	xe_assert(xe, !(guc_ct_size() % PAGE_SIZE));
 
+	ct->g2h_wq = alloc_ordered_workqueue("xe-g2h-wq", 0);
+	if (!ct->g2h_wq)
+		return -ENOMEM;
+
 	spin_lock_init(&ct->fast_lock);
 	xa_init(&ct->fence_lookup);
 	INIT_WORK(&ct->g2h_worker, g2h_worker_func);
diff --git a/drivers/gpu/drm/xe/xe_guc_ct.h b/drivers/gpu/drm/xe/xe_guc_ct.h
index 9ecb67db8ec40..86b67b775eaba 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct.h
+++ b/drivers/gpu/drm/xe/xe_guc_ct.h
@@ -28,7 +28,7 @@ static inline void xe_guc_ct_irq_handler(struct xe_guc_ct *ct)
 		return;
 
 	wake_up_all(&ct->wq);
-	queue_work(system_unbound_wq, &ct->g2h_worker);
+	queue_work(ct->g2h_wq, &ct->g2h_worker);
 	xe_guc_ct_fast_path(ct);
 }
 
diff --git a/drivers/gpu/drm/xe/xe_guc_ct_types.h b/drivers/gpu/drm/xe/xe_guc_ct_types.h
index d814d4ee3fc65..bd945ed3ee41e 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct_types.h
+++ b/drivers/gpu/drm/xe/xe_guc_ct_types.h
@@ -106,6 +106,8 @@ struct xe_guc_ct {
 	wait_queue_head_t wq;
 	/** @g2h_fence_wq: wait queue used for G2H fencing */
 	wait_queue_head_t g2h_fence_wq;
+	/** @g2h_wq: used to process G2H */
+	struct workqueue_struct *g2h_wq;
 	/** @msg: Message buffer */
 	u32 msg[GUC_CTB_MSG_MAX_LEN];
 	/** @fast_msg: Message buffer */