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| author | NeilBrown <neilb@suse.de> | 2011-04-18 12:25:42 +0400 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2011-04-18 12:25:42 +0400 |
| commit | 97658cdd3af7d01461874c93b89afa4a2465e7c6 (patch) | |
| tree | d4e2f930850eb3981307a3eec8c86399dcebf68a /drivers/md/md.h | |
| parent | 482c083492ddaa32ef5864bae3d143dc8bcdf7d1 (diff) | |
| download | linux-97658cdd3af7d01461874c93b89afa4a2465e7c6.tar.xz | |
md: provide generic support for handling unplug callbacks.
When an md device adds a request to a queue, it can call
mddev_check_plugged.
If this succeeds then we know that the md thread will be woken up
shortly, and ->plug_cnt will be non-zero until then, so some
processing can be delayed.
If it fails, then no unplug callback is expected and the make_request
function needs to do whatever is required to make the request happen.
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md/md.h')
| -rw-r--r-- | drivers/md/md.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/md.h b/drivers/md/md.h index fad90228672f..0b1fd3f1d85b 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -179,6 +179,9 @@ struct mddev_s int delta_disks, new_level, new_layout; int new_chunk_sectors; + atomic_t plug_cnt; /* If device is expecting + * more bios soon. + */ struct mdk_thread_s *thread; /* management thread */ struct mdk_thread_s *sync_thread; /* doing resync or reconstruct */ sector_t curr_resync; /* last block scheduled */ @@ -508,4 +511,5 @@ extern struct bio *bio_clone_mddev(struct bio *bio, gfp_t gfp_mask, mddev_t *mddev); extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs, mddev_t *mddev); +extern int mddev_check_plugged(mddev_t *mddev); #endif /* _MD_MD_H */ |