block: allow initialization of previously allocated request_queue
blk_init_queue() allocates the request_queue structure and then
initializes it as needed (request_fn, elevator, etc).
Split initialization out to blk_init_allocated_queue_node.
Introduce blk_init_allocated_queue wrapper function to model existing
blk_init_queue and blk_init_queue_node interfaces.
Export elv_register_queue to allow a newly added elevator to be
registered with sysfs. Export elv_unregister_queue for symmetry.
These changes allow DM to initialize a device's request_queue with more
precision. In particular, DM no longer unconditionally initializes a
full request_queue (elevator et al). It only does so for a
request-based DM device.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-core.c b/block/blk-core.c
index e9a5ae2..3bc5579 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -572,6 +572,22 @@
{
struct request_queue *q = blk_alloc_queue_node(GFP_KERNEL, node_id);
+ return blk_init_allocated_queue_node(q, rfn, lock, node_id);
+}
+EXPORT_SYMBOL(blk_init_queue_node);
+
+struct request_queue *
+blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
+ spinlock_t *lock)
+{
+ return blk_init_allocated_queue_node(q, rfn, lock, -1);
+}
+EXPORT_SYMBOL(blk_init_allocated_queue);
+
+struct request_queue *
+blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
+ spinlock_t *lock, int node_id)
+{
if (!q)
return NULL;
@@ -605,7 +621,7 @@
blk_put_queue(q);
return NULL;
}
-EXPORT_SYMBOL(blk_init_queue_node);
+EXPORT_SYMBOL(blk_init_allocated_queue_node);
int blk_get_queue(struct request_queue *q)
{
diff --git a/block/elevator.c b/block/elevator.c
index 5e73459..6df2b50 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -930,6 +930,7 @@
}
return error;
}
+EXPORT_SYMBOL(elv_register_queue);
static void __elv_unregister_queue(struct elevator_queue *e)
{
@@ -942,6 +943,7 @@
if (q)
__elv_unregister_queue(q->elevator);
}
+EXPORT_SYMBOL(elv_unregister_queue);
void elv_register(struct elevator_type *e)
{
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3ac2bd2..346fd48 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -921,7 +921,12 @@
*/
extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
spinlock_t *lock, int node_id);
+extern struct request_queue *blk_init_allocated_queue_node(struct request_queue *,
+ request_fn_proc *,
+ spinlock_t *, int node_id);
extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
+extern struct request_queue *blk_init_allocated_queue(struct request_queue *,
+ request_fn_proc *, spinlock_t *);
extern void blk_cleanup_queue(struct request_queue *);
extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
extern void blk_queue_bounce_limit(struct request_queue *, u64);