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blk: centralize non-request unplug handling.

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Both md and umem has similar code for getting notified on an
blk_finish_plug event.
Centralize this code in block/ and allow each driver to
provide its distinctive difference.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
NeilBrown
2012-07-31 09:08:14 +02:00
committed by Jens Axboe
parent 0021b7bc04
commit 9cbb175088
5 changed files with 49 additions and 83 deletions
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56
drivers/md/md.c
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@@ -498,59 +498,13 @@ void md_flush_request(struct mddev *mddev, struct bio *bio)
}
EXPORT_SYMBOL(md_flush_request);
/* Support for plugging.
* This mirrors the plugging support in request_queue, but does not
* require having a whole queue or request structures.
* We allocate an md_plug_cb for each md device and each thread it gets
* plugged on. This links tot the private plug_handle structure in the
* personality data where we keep a count of the number of outstanding
* plugs so other code can see if a plug is active.
*/
struct md_plug_cb {
struct blk_plug_cb cb;
struct mddev *mddev;
};
static void plugger_unplug(struct blk_plug_cb *cb)
void md_unplug(struct blk_plug_cb *cb)
{
struct md_plug_cb *mdcb = container_of(cb, struct md_plug_cb, cb);
md_wakeup_thread(mdcb->mddev->thread);
kfree(mdcb);
struct mddev *mddev = cb->data;
md_wakeup_thread(mddev->thread);
kfree(cb);
}
/* Check that an unplug wakeup will come shortly.
* If not, wakeup the md thread immediately
*/
int mddev_check_plugged(struct mddev *mddev)
{
struct blk_plug *plug = current->plug;
struct md_plug_cb *mdcb;
if (!plug)
return 0;
list_for_each_entry(mdcb, &plug->cb_list, cb.list) {
if (mdcb->cb.callback == plugger_unplug &&
mdcb->mddev == mddev) {
/* Already on the list, move to top */
if (mdcb != list_first_entry(&plug->cb_list,
struct md_plug_cb,
cb.list))
list_move(&mdcb->cb.list, &plug->cb_list);
return 1;
}
}
/* Not currently on the callback list */
mdcb = kmalloc(sizeof(*mdcb), GFP_ATOMIC);
if (!mdcb)
return 0;
mdcb->mddev = mddev;
mdcb->cb.callback = plugger_unplug;
list_add(&mdcb->cb.list, &plug->cb_list);
return 1;
}
EXPORT_SYMBOL_GPL(mddev_check_plugged);
EXPORT_SYMBOL(md_unplug);
static inline struct mddev *mddev_get(struct mddev *mddev)
{