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.c | |
parent | 4e7f1f9089660aec3b5ab2645ce62777c6f4c6a2 (diff) | |
download | linux-6beca5eb6e801aea810da6cbc4990d96e6c1c0bc.tar.bz2 |
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.c')
-rw-r--r-- | drivers/md/dm-bio-prison.c | 139 |
1 files changed, 72 insertions, 67 deletions
diff --git a/drivers/md/dm-bio-prison.c b/drivers/md/dm-bio-prison.c index d9d3f1c7b662..ca5771d3ffd7 100644 --- a/drivers/md/dm-bio-prison.c +++ b/drivers/md/dm-bio-prison.c @@ -16,7 +16,6 @@ struct dm_bio_prison_cell { struct hlist_node list; - struct dm_bio_prison *prison; struct dm_cell_key key; struct bio *holder; struct bio_list bios; @@ -87,6 +86,19 @@ void dm_bio_prison_destroy(struct dm_bio_prison *prison) } EXPORT_SYMBOL_GPL(dm_bio_prison_destroy); +struct dm_bio_prison_cell *dm_bio_prison_alloc_cell(struct dm_bio_prison *prison, gfp_t gfp) +{ + return mempool_alloc(prison->cell_pool, gfp); +} +EXPORT_SYMBOL_GPL(dm_bio_prison_alloc_cell); + +void dm_bio_prison_free_cell(struct dm_bio_prison *prison, + struct dm_bio_prison_cell *cell) +{ + mempool_free(cell, prison->cell_pool); +} +EXPORT_SYMBOL_GPL(dm_bio_prison_free_cell); + static uint32_t hash_key(struct dm_bio_prison *prison, struct dm_cell_key *key) { const unsigned long BIG_PRIME = 4294967291UL; @@ -114,91 +126,86 @@ static struct dm_bio_prison_cell *__search_bucket(struct hlist_head *bucket, return NULL; } -/* - * This may block if a new cell needs allocating. You must ensure that - * cells will be unlocked even if the calling thread is blocked. - * - * 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 **ref) +static void __setup_new_cell(struct dm_bio_prison *prison, + struct dm_cell_key *key, + struct bio *holder, + uint32_t hash, + struct dm_bio_prison_cell *cell) { - int r = 1; - unsigned long flags; - uint32_t hash = hash_key(prison, key); - struct dm_bio_prison_cell *cell, *cell2; - - BUG_ON(hash > prison->nr_buckets); - - spin_lock_irqsave(&prison->lock, flags); - - cell = __search_bucket(prison->cells + hash, key); - if (cell) { - bio_list_add(&cell->bios, inmate); - goto out; - } + memcpy(&cell->key, key, sizeof(cell->key)); + cell->holder = holder; + bio_list_init(&cell->bios); + hlist_add_head(&cell->list, prison->cells + hash); +} - /* - * Allocate a new cell - */ - spin_unlock_irqrestore(&prison->lock, flags); - cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO); - spin_lock_irqsave(&prison->lock, flags); +static int __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) +{ + uint32_t hash = hash_key(prison, key); + struct dm_bio_prison_cell *cell; - /* - * We've been unlocked, so we have to double check that - * nobody else has inserted this cell in the meantime. - */ cell = __search_bucket(prison->cells + hash, key); if (cell) { - mempool_free(cell2, prison->cell_pool); - bio_list_add(&cell->bios, inmate); - goto out; + if (inmate) + bio_list_add(&cell->bios, inmate); + *cell_result = cell; + return 1; } - /* - * Use new cell. - */ - cell = cell2; - - cell->prison = prison; - memcpy(&cell->key, key, sizeof(cell->key)); - cell->holder = inmate; - bio_list_init(&cell->bios); - hlist_add_head(&cell->list, prison->cells + hash); + __setup_new_cell(prison, key, inmate, hash, cell_prealloc); + *cell_result = cell_prealloc; + return 0; +} - r = 0; +static int 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) +{ + int r; + unsigned long flags; -out: + spin_lock_irqsave(&prison->lock, flags); + r = __bio_detain(prison, key, inmate, cell_prealloc, cell_result); spin_unlock_irqrestore(&prison->lock, flags); - *ref = cell; - return r; } + +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) +{ + return bio_detain(prison, key, inmate, cell_prealloc, cell_result); +} EXPORT_SYMBOL_GPL(dm_bio_detain); /* * @inmates must have been initialised prior to this call */ -static void __cell_release(struct dm_bio_prison_cell *cell, struct bio_list *inmates) +static void __cell_release(struct dm_bio_prison_cell *cell, + struct bio_list *inmates) { - struct dm_bio_prison *prison = cell->prison; - hlist_del(&cell->list); if (inmates) { - bio_list_add(inmates, cell->holder); + if (cell->holder) + bio_list_add(inmates, cell->holder); bio_list_merge(inmates, &cell->bios); } - - mempool_free(cell, prison->cell_pool); } -void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios) +void dm_cell_release(struct dm_bio_prison *prison, + struct dm_bio_prison_cell *cell, + struct bio_list *bios) { unsigned long flags; - struct dm_bio_prison *prison = cell->prison; spin_lock_irqsave(&prison->lock, flags); __cell_release(cell, bios); @@ -209,20 +216,18 @@ EXPORT_SYMBOL_GPL(dm_cell_release); /* * Sometimes we don't want the holder, just the additional bios. */ -static void __cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates) +static void __cell_release_no_holder(struct dm_bio_prison_cell *cell, + struct bio_list *inmates) { - struct dm_bio_prison *prison = cell->prison; - hlist_del(&cell->list); bio_list_merge(inmates, &cell->bios); - - mempool_free(cell, prison->cell_pool); } -void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates) +void dm_cell_release_no_holder(struct dm_bio_prison *prison, + struct dm_bio_prison_cell *cell, + struct bio_list *inmates) { unsigned long flags; - struct dm_bio_prison *prison = cell->prison; spin_lock_irqsave(&prison->lock, flags); __cell_release_no_holder(cell, inmates); @@ -230,9 +235,9 @@ void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list } EXPORT_SYMBOL_GPL(dm_cell_release_no_holder); -void dm_cell_error(struct dm_bio_prison_cell *cell) +void dm_cell_error(struct dm_bio_prison *prison, + struct dm_bio_prison_cell *cell) { - struct dm_bio_prison *prison = cell->prison; struct bio_list bios; struct bio *bio; unsigned long flags; |