Commit 549dd786 authored by Matthew Brost's avatar Matthew Brost
Browse files

drm/xe: Move VM dma-resv lock from xe_exec_queue_create to __xe_exec_queue_init 



The critical section which requires the VM dma-resv is the call
xe_lrc_create in __xe_exec_queue_init. Move this lock to
__xe_exec_queue_init holding it just around xe_lrc_create. Not only is
good practice, this also fixes a locking double of the VM dma-resv in
the error paths of __xe_exec_queue_init as xe_lrc_put tries to acquire
this too resulting in a deadlock.

Fixes: dd08ebf6 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: default avatarMatthew Brost <matthew.brost@intel.com>
Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240724152831.1848325-1-matthew.brost@intel.com
parent 5bdacb09

drivers/gpu/drm/xe/xe_exec_queue.c

+14 −9
Original line number Diff line number Diff line
@@ -105,22 +105,35 @@ static struct xe_exec_queue *__xe_exec_queue_alloc(struct xe_device *xe, 


static int __xe_exec_queue_init(struct xe_exec_queue *q)

{

	struct xe_vm *vm = q->vm;

	int i, err;



	if (vm) {

		err = xe_vm_lock(vm, true);

		if (err)

			return err;

	}



	for (i = 0; i < q->width; ++i) {

		q->lrc[i] = xe_lrc_create(q->hwe, q->vm, SZ_16K);

		if (IS_ERR(q->lrc[i])) {

			err = PTR_ERR(q->lrc[i]);

			goto err_lrc;

			goto err_unlock;

		}

	}



	if (vm)

		xe_vm_unlock(vm);



	err = q->ops->init(q);

	if (err)

		goto err_lrc;



	return 0;



err_unlock:

	if (vm)

		xe_vm_unlock(vm);

err_lrc:

	for (i = i - 1; i >= 0; --i)

		xe_lrc_put(q->lrc[i]);
@@ -140,15 +153,7 @@ struct xe_exec_queue *xe_exec_queue_create(struct xe_device *xe, struct xe_vm *v 
	if (IS_ERR(q))

		return q;



	if (vm) {

		err = xe_vm_lock(vm, true);

		if (err)

			goto err_post_alloc;

	}



	err = __xe_exec_queue_init(q);

	if (vm)

		xe_vm_unlock(vm);

	if (err)

		goto err_post_alloc;