Re: [PATCH v3 3/7] drm/xe: Add dedicated message lock

[Niranjana Vishwanathapura]

On Thu, Oct 16, 2025 at 01:48:22PM -0700, Matthew Brost wrote:

Stop abusing DRM scheduler job list lock for messages, add dedicated
message lock.

Signed-off-by: Matthew Brost <matthew.br...@intel.com>

LGTM.
Reviewed-by: Niranjana Vishwanathapura <niranjana.vishwanathap...@intel.com>

---
drivers/gpu/drm/xe/xe_gpu_scheduler.c       | 5 +++--
drivers/gpu/drm/xe/xe_gpu_scheduler.h       | 4 ++--
drivers/gpu/drm/xe/xe_gpu_scheduler_types.h | 2 ++
3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gpu_scheduler.c 
b/drivers/gpu/drm/xe/xe_gpu_scheduler.c
index f91e06d03511..f4f23317191f 100644
--- a/drivers/gpu/drm/xe/xe_gpu_scheduler.c
+++ b/drivers/gpu/drm/xe/xe_gpu_scheduler.c
@@ -77,6 +77,7 @@ int xe_sched_init(struct xe_gpu_scheduler *sched,
        };

        sched->ops = xe_ops;
+       spin_lock_init(&sched->msg_lock);
        INIT_LIST_HEAD(&sched->msgs);
        INIT_WORK(&sched->work_process_msg, xe_sched_process_msg_work);

@@ -117,7 +118,7 @@ void xe_sched_add_msg(struct xe_gpu_scheduler *sched,
void xe_sched_add_msg_locked(struct xe_gpu_scheduler *sched,
                             struct xe_sched_msg *msg)
{
-       lockdep_assert_held(&sched->base.job_list_lock);
+       lockdep_assert_held(&sched->msg_lock);

        list_add_tail(&msg->link, &sched->msgs);
        xe_sched_process_msg_queue(sched);
@@ -131,7 +132,7 @@ void xe_sched_add_msg_locked(struct xe_gpu_scheduler *sched,
void xe_sched_add_msg_head(struct xe_gpu_scheduler *sched,
                           struct xe_sched_msg *msg)
{
-       lockdep_assert_held(&sched->base.job_list_lock);
+       lockdep_assert_held(&sched->msg_lock);

        list_add(&msg->link, &sched->msgs);
        xe_sched_process_msg_queue(sched);
diff --git a/drivers/gpu/drm/xe/xe_gpu_scheduler.h 
b/drivers/gpu/drm/xe/xe_gpu_scheduler.h
index 9955397aaaa9..b971b6b69419 100644
--- a/drivers/gpu/drm/xe/xe_gpu_scheduler.h
+++ b/drivers/gpu/drm/xe/xe_gpu_scheduler.h
@@ -33,12 +33,12 @@ void xe_sched_add_msg_head(struct xe_gpu_scheduler *sched,

static inline void xe_sched_msg_lock(struct xe_gpu_scheduler *sched)
{
-       spin_lock(&sched->base.job_list_lock);
+       spin_lock(&sched->msg_lock);
}

static inline void xe_sched_msg_unlock(struct xe_gpu_scheduler *sched)
{
-       spin_unlock(&sched->base.job_list_lock);
+       spin_unlock(&sched->msg_lock);
}

static inline void xe_sched_stop(struct xe_gpu_scheduler *sched)
diff --git a/drivers/gpu/drm/xe/xe_gpu_scheduler_types.h 
b/drivers/gpu/drm/xe/xe_gpu_scheduler_types.h
index 6731b13da8bb..63d9bf92583c 100644
--- a/drivers/gpu/drm/xe/xe_gpu_scheduler_types.h
+++ b/drivers/gpu/drm/xe/xe_gpu_scheduler_types.h
@@ -47,6 +47,8 @@ struct xe_gpu_scheduler {
        const struct xe_sched_backend_ops       *ops;
        /** @msgs: list of messages to be processed in @work_process_msg */
        struct list_head                        msgs;
+       /** @msg_lock: Message lock */
+       spinlock_t                              msg_lock;
        /** @work_process_msg: processes messages */
        struct work_struct              work_process_msg;
};
--
2.34.1