ublk: rename mm_lock as lock

Rename mm_lock field of ublk_device as lock, so that this lock can be reused
for protecting access of ub->ub_disk, which will be used for simplifying
ublk_abort_queue() by quiesce queue in next patch.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20231009093324.957829-5-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/ublk_drv.c

@@ -170,7 +170,7 @@ struct ublk_device {
 
 	struct mutex		mutex;
 
-	spinlock_t		mm_lock;
+	spinlock_t		lock;
 	struct mm_struct	*mm;
 
 	struct ublk_params	params;
@@ -1362,12 +1362,12 @@ static int ublk_ch_mmap(struct file *filp, struct vm_area_struct *vma)
 	unsigned long pfn, end, phys_off = vma->vm_pgoff << PAGE_SHIFT;
 	int q_id, ret = 0;
 
-	spin_lock(&ub->mm_lock);
+	spin_lock(&ub->lock);
 	if (!ub->mm)
 		ub->mm = current->mm;
 	if (current->mm != ub->mm)
 		ret = -EINVAL;
-	spin_unlock(&ub->mm_lock);
+	spin_unlock(&ub->lock);
 
 	if (ret)
 		return ret;
@@ -2349,7 +2349,7 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
 	if (!ub)
 		goto out_unlock;
 	mutex_init(&ub->mutex);
-	spin_lock_init(&ub->mm_lock);
+	spin_lock_init(&ub->lock);
 	INIT_WORK(&ub->quiesce_work, ublk_quiesce_work_fn);
 	INIT_WORK(&ub->stop_work, ublk_stop_work_fn);
 	INIT_DELAYED_WORK(&ub->monitor_work, ublk_daemon_monitor_work);