On Sat, Aug 08 2009 at 11:42am -0400,
Mike Snitzer <snitzer@xxxxxxxxxx> wrote:
> On Sat, Aug 08 2009 at 12:55am -0400,
> Nikanth Karthikesan <knikanth@xxxxxxx> wrote:
>
> > Export a way to delay initializing a request_queue after allocating it. This
> > is needed by device-mapper devices, as they create the queue on device
> > creation time, but they decide whether it would use the elevator and requests
> > only after first successful table load. Only request-based dm-devices use the
> > elevator and requests. Without this either one needs to initialize and free
> > the mempool and elevator, if it was a bio-based dm-device or leave it
> > allocated, as it is currently done.
> >
> > Signed-off-by: Nikanth Karthikesan <knikanth@xxxxxxx>
>
> This patch needed to be refreshed to account for the changes from this
> recent commit: a4e7d46407d73f35d217013b363b79a8f8eafcaa
>
> I've attached a refreshed patch.
Err, I dropped a hunk in the process... here is the refreshed patch
inlined. Figured I'd save you the busy-work for when you get V2
together.
> Though I still have questions/feedback below.
Hopefully V2 will address my questions/feedback.
Regards,
Mike
---
Export a way to delay initializing a request_queue after allocating it. This
is needed by device-mapper devices, as they create the queue on device
creation time, but they decide whether it would use the elevator and requests
only after first successful table load. Only request-based dm-devices use the
elevator and requests. Without this either one needs to initialize and free
the mempool and elevator, if it was a bio-based dm-device or leave it
allocated, as it is currently done.
Signed-off-by: Nikanth Karthikesan <knikanth@xxxxxxx>
---
Index: linux-2.6/block/blk-core.c
===================================================================
--- linux-2.6.orig/block/blk-core.c
+++ linux-2.6/block/blk-core.c
@@ -495,6 +495,8 @@ struct request_queue *blk_alloc_queue_no
if (!q)
return NULL;
+ q->node = node_id;
+
q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug;
q->backing_dev_info.unplug_io_data = q;
q->backing_dev_info.ra_pages =
@@ -569,12 +571,25 @@ blk_init_queue_node(request_fn_proc *rfn
if (!q)
return NULL;
- q->node = node_id;
- if (blk_init_free_list(q)) {
+ if (blk_init_allocated_queue(q, rfn, lock)) {
+ blk_put_queue(q);
kmem_cache_free(blk_requestq_cachep, q);
return NULL;
}
+ return q;
+}
+EXPORT_SYMBOL(blk_init_queue_node);
+
+int blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
+ spinlock_t *lock)
+{
+ int err = 0;
+
+ err = blk_init_free_list(q);
+ if (err)
+ goto out;
+
q->request_fn = rfn;
q->prep_rq_fn = NULL;
q->unplug_fn = generic_unplug_device;
@@ -591,15 +606,20 @@ blk_init_queue_node(request_fn_proc *rfn
/*
* all done
*/
- if (!elevator_init(q, NULL)) {
- blk_queue_congestion_threshold(q);
- return q;
- }
+ err = elevator_init(q, NULL);
+ if (err)
+ goto free_and_out;
- blk_put_queue(q);
- return NULL;
+ blk_queue_congestion_threshold(q);
+
+ return 0;
+
+free_and_out:
+ mempool_destroy(q->rq.rq_pool);
+out:
+ return err;
}
-EXPORT_SYMBOL(blk_init_queue_node);
+EXPORT_SYMBOL(blk_init_allocated_queue);
int blk_get_queue(struct request_queue *q)
{
Index: linux-2.6/include/linux/blkdev.h
===================================================================
--- linux-2.6.orig/include/linux/blkdev.h
+++ linux-2.6/include/linux/blkdev.h
@@ -901,6 +901,8 @@ extern void blk_abort_queue(struct reque
extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn,
spinlock_t *lock, int node_id);
extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *);
+extern int blk_init_allocated_queue(struct request_queue *q,
+ request_fn_proc *rfn, spinlock_t *lock);
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);
--
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