block: remove elevator queue's type check in elv_attr_show/store()

JIRA: https://issues.redhat.com/browse/RHEL-106845

commit e25ee50
Author: Ming Lei <ming.lei@redhat.com>
Date:   Mon May 5 22:17:56 2025 +0800

    block: remove elevator queue's type check in elv_attr_show/store()

    elevatore queue's type is assigned since its allocation, and never
    get cleared until it is released.

    So its ->type is always not NULL, remove the unnecessary check.

    Reviewed-by: Hannes Reinecke <hare@suse.de>
    Reviewed-by: Christoph Hellwig <hch@lst.de>
    Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
    Suggested-by: Christoph Hellwig <hch@lst.de>
    Signed-off-by: Ming Lei <ming.lei@redhat.com>
    Link: https://lore.kernel.org/r/20250505141805.2751237-19-ming.lei@redhat.com
    Signed-off-by: Jens Axboe <axboe@kernel.dk>

Signed-off-by: Ming Lei <ming.lei@redhat.com>

Author: Ming Lei

block/elevator.c

@@ -425,7 +425,7 @@ elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
 
 	e = container_of(kobj, struct elevator_queue, kobj);
 	mutex_lock(&e->sysfs_lock);
-	error = e->type ? entry->show(e, page) : -ENOENT;
+	error = entry->show(e, page);
 	mutex_unlock(&e->sysfs_lock);
 	return error;
 }
@@ -443,7 +443,7 @@ elv_attr_store(struct kobject *kobj, struct attribute *attr,
 
 	e = container_of(kobj, struct elevator_queue, kobj);
 	mutex_lock(&e->sysfs_lock);
-	error = e->type ? entry->store(e, page, length) : -ENOENT;
+	error = entry->store(e, page, length);
 	mutex_unlock(&e->sysfs_lock);
 	return error;
 }