diff options
| author | Joe Thornber <ejt@redhat.com> | 2013-03-01 22:45:50 +0000 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2013-03-01 22:45:50 +0000 |
| commit | 6beca5eb6e801aea810da6cbc4990d96e6c1c0bc (patch) | |
| tree | 37586c9ecdd7bbc89ce4db07abde3ca32d6a8e1c /drivers/md/dm-bio-prison.h | |
| parent | 4e7f1f9089660aec3b5ab2645ce62777c6f4c6a2 (diff) | |
dm bio prison: pass cell memory in
Change the dm_bio_prison interface so that instead of allocating memory
internally, dm_bio_detain is supplied with a pre-allocated cell each
time it is called.
This enables a subsequent patch to move the allocation of the struct
dm_bio_prison_cell outside the thin target's mapping function so it can
no longer block there.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-bio-prison.h')
| -rw-r--r-- | drivers/md/dm-bio-prison.h | 35 |
1 files changed, 27 insertions, 8 deletions
diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h index 53d1a7a84e2f..11af2182101b 100644 --- a/drivers/md/dm-bio-prison.h +++ b/drivers/md/dm-bio-prison.h @@ -35,17 +35,36 @@ struct dm_bio_prison *dm_bio_prison_create(unsigned nr_cells); void dm_bio_prison_destroy(struct dm_bio_prison *prison); /* - * This may block if a new cell needs allocating. You must ensure that - * cells will be unlocked even if the calling thread is blocked. + * These two functions just wrap a mempool. This is a transitory step: + * Eventually all bio prison clients should manage their own cell memory. * - * Returns 1 if the cell was already held, 0 if @inmate is the new holder. + * Like mempool_alloc(), dm_bio_prison_alloc_cell() can only fail if called + * in interrupt context or passed GFP_NOWAIT. */ -int dm_bio_detain(struct dm_bio_prison *prison, struct dm_cell_key *key, - struct bio *inmate, struct dm_bio_prison_cell **ref); +struct dm_bio_prison_cell *dm_bio_prison_alloc_cell(struct dm_bio_prison *prison, + gfp_t gfp); +void dm_bio_prison_free_cell(struct dm_bio_prison *prison, + struct dm_bio_prison_cell *cell); -void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios); -void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates); -void dm_cell_error(struct dm_bio_prison_cell *cell); +/* + * An atomic op that combines retrieving a cell, and adding a bio to it. + * + * Returns 1 if the cell was already held, 0 if @inmate is the new holder. + */ +int dm_bio_detain(struct dm_bio_prison *prison, + struct dm_cell_key *key, + struct bio *inmate, + struct dm_bio_prison_cell *cell_prealloc, + struct dm_bio_prison_cell **cell_result); + +void dm_cell_release(struct dm_bio_prison *prison, + struct dm_bio_prison_cell *cell, + struct bio_list *bios); +void dm_cell_release_no_holder(struct dm_bio_prison *prison, + struct dm_bio_prison_cell *cell, + struct bio_list *inmates); +void dm_cell_error(struct dm_bio_prison *prison, + struct dm_bio_prison_cell *cell); /*----------------------------------------------------------------*/ |