Commit e694179a authored by Niranjana Vishwanathapura's avatar Niranjana Vishwanathapura
Browse files

drm/xe/multi_queue: Protect priority against concurrent access 



Use a spinlock to protect multi-queue priority being concurrently
updated by multiple set_priority ioctls and to protect against
concurrent read and write to this field.

v2: Update documentation, remove WRITE/READ_LOCK() (Thomas)
    Use scoped_guard, reduced lock scope (Matt Brost)
v3: Fix author (checkpatch)

Signed-off-by: default avatarNiranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Reviewed-by: default avatarMatthew Brost <matthew.brost@intel.com>
Reviewed-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patch.msgid.link/20260126174241.3470390-2-niranjana.vishwanathapura@intel.com
parent 7755ed58

drivers/gpu/drm/xe/xe_exec_queue.c

+1 −0
Original line number Diff line number Diff line
@@ -230,6 +230,7 @@ static struct xe_exec_queue *__xe_exec_queue_alloc(struct xe_device *xe, 
	INIT_LIST_HEAD(&q->multi_gt_link);

	INIT_LIST_HEAD(&q->hw_engine_group_link);

	INIT_LIST_HEAD(&q->pxp.link);

	spin_lock_init(&q->multi_queue.lock);

	q->multi_queue.priority = XE_MULTI_QUEUE_PRIORITY_NORMAL;



	q->sched_props.timeslice_us = hwe->eclass->sched_props.timeslice_us;

drivers/gpu/drm/xe/xe_exec_queue_types.h

+6 −1
Original line number Diff line number Diff line
@@ -161,8 +161,13 @@ struct xe_exec_queue { 
		struct xe_exec_queue_group *group;

		/** @multi_queue.link: Link into group's secondary queues list */

		struct list_head link;

		/** @multi_queue.priority: Queue priority within the multi-queue group */

		/**

		 * @multi_queue.priority: Queue priority within the multi-queue group.

		 * It is protected by @multi_queue.lock.

		 */

		enum xe_multi_queue_priority priority;

		/** @multi_queue.lock: Lock for protecting certain members */

		spinlock_t lock;

		/** @multi_queue.pos: Position of queue within the multi-queue group */

		u8 pos;

		/** @multi_queue.valid: Queue belongs to a multi queue group */

drivers/gpu/drm/xe/xe_guc_submit.c

+15 −4
Original line number Diff line number Diff line
@@ -804,6 +804,7 @@ static void xe_guc_exec_queue_group_cgp_sync(struct xe_guc *guc, 
{

	struct xe_exec_queue_group *group = q->multi_queue.group;

	struct xe_device *xe = guc_to_xe(guc);

	enum xe_multi_queue_priority priority;

	long ret;



	/*
@@ -827,7 +828,10 @@ static void xe_guc_exec_queue_group_cgp_sync(struct xe_guc *guc, 
		return;

	}



	xe_lrc_set_multi_queue_priority(q->lrc[0], q->multi_queue.priority);

	scoped_guard(spinlock, &q->multi_queue.lock)

		priority = q->multi_queue.priority;



	xe_lrc_set_multi_queue_priority(q->lrc[0], priority);

	xe_guc_exec_queue_group_cgp_update(xe, q);



	WRITE_ONCE(group->sync_pending, true);
@@ -2181,15 +2185,22 @@ static int guc_exec_queue_set_multi_queue_priority(struct xe_exec_queue *q, 


	xe_gt_assert(guc_to_gt(exec_queue_to_guc(q)), xe_exec_queue_is_multi_queue(q));



	if (q->multi_queue.priority == priority ||

	    exec_queue_killed_or_banned_or_wedged(q))

	if (exec_queue_killed_or_banned_or_wedged(q))

		return 0;



	msg = kmalloc(sizeof(*msg), GFP_KERNEL);

	if (!msg)

		return -ENOMEM;



	scoped_guard(spinlock, &q->multi_queue.lock) {

		if (q->multi_queue.priority == priority) {

			kfree(msg);

			return 0;

		}



		q->multi_queue.priority = priority;

	}



	guc_exec_queue_add_msg(q, msg, SET_MULTI_QUEUE_PRIORITY);



	return 0;