From 6beca5eb6e801aea810da6cbc4990d96e6c1c0bc Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Fri, 1 Mar 2013 22:45:50 +0000 Subject: 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 Signed-off-by: Alasdair G Kergon --- drivers/md/dm-thin.c | 103 ++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 77 insertions(+), 26 deletions(-) (limited to 'drivers/md/dm-thin.c') diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 35d9d0396cc2..5304e3a29a14 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -229,6 +229,54 @@ struct thin_c { /*----------------------------------------------------------------*/ +static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio, + struct dm_bio_prison_cell **cell_result) +{ + int r; + struct dm_bio_prison_cell *cell_prealloc; + + /* + * Allocate a cell from the prison's mempool. + * This might block but it can't fail. + */ + cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO); + + r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result); + if (r) + /* + * We reused an old cell; we can get rid of + * the new one. + */ + dm_bio_prison_free_cell(pool->prison, cell_prealloc); + + return r; +} + +static void cell_release(struct pool *pool, + struct dm_bio_prison_cell *cell, + struct bio_list *bios) +{ + dm_cell_release(pool->prison, cell, bios); + dm_bio_prison_free_cell(pool->prison, cell); +} + +static void cell_release_no_holder(struct pool *pool, + struct dm_bio_prison_cell *cell, + struct bio_list *bios) +{ + dm_cell_release_no_holder(pool->prison, cell, bios); + dm_bio_prison_free_cell(pool->prison, cell); +} + +static void cell_error(struct pool *pool, + struct dm_bio_prison_cell *cell) +{ + dm_cell_error(pool->prison, cell); + dm_bio_prison_free_cell(pool->prison, cell); +} + +/*----------------------------------------------------------------*/ + /* * A global list of pools that uses a struct mapped_device as a key. */ @@ -524,14 +572,14 @@ static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell) unsigned long flags; spin_lock_irqsave(&pool->lock, flags); - dm_cell_release(cell, &pool->deferred_bios); + cell_release(pool, cell, &pool->deferred_bios); spin_unlock_irqrestore(&tc->pool->lock, flags); wake_worker(pool); } /* - * Same as cell_defer except it omits the original holder of the cell. + * Same as cell_defer above, except it omits the original holder of the cell. */ static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell) { @@ -539,7 +587,7 @@ static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *c unsigned long flags; spin_lock_irqsave(&pool->lock, flags); - dm_cell_release_no_holder(cell, &pool->deferred_bios); + cell_release_no_holder(pool, cell, &pool->deferred_bios); spin_unlock_irqrestore(&pool->lock, flags); wake_worker(pool); @@ -549,13 +597,14 @@ static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m) { if (m->bio) m->bio->bi_end_io = m->saved_bi_end_io; - dm_cell_error(m->cell); + cell_error(m->tc->pool, m->cell); list_del(&m->list); mempool_free(m, m->tc->pool->mapping_pool); } static void process_prepared_mapping(struct dm_thin_new_mapping *m) { struct thin_c *tc = m->tc; + struct pool *pool = tc->pool; struct bio *bio; int r; @@ -564,7 +613,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m) bio->bi_end_io = m->saved_bi_end_io; if (m->err) { - dm_cell_error(m->cell); + cell_error(pool, m->cell); goto out; } @@ -576,7 +625,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m) r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block); if (r) { DMERR_LIMIT("dm_thin_insert_block() failed"); - dm_cell_error(m->cell); + cell_error(pool, m->cell); goto out; } @@ -594,7 +643,7 @@ static void process_prepared_mapping(struct dm_thin_new_mapping *m) out: list_del(&m->list); - mempool_free(m, tc->pool->mapping_pool); + mempool_free(m, pool->mapping_pool); } static void process_prepared_discard_fail(struct dm_thin_new_mapping *m) @@ -745,7 +794,7 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, if (r < 0) { mempool_free(m, pool->mapping_pool); DMERR_LIMIT("dm_kcopyd_copy() failed"); - dm_cell_error(cell); + cell_error(pool, cell); } } } @@ -811,7 +860,7 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, if (r < 0) { mempool_free(m, pool->mapping_pool); DMERR_LIMIT("dm_kcopyd_zero() failed"); - dm_cell_error(cell); + cell_error(pool, cell); } } } @@ -917,13 +966,13 @@ static void retry_on_resume(struct bio *bio) spin_unlock_irqrestore(&pool->lock, flags); } -static void no_space(struct dm_bio_prison_cell *cell) +static void no_space(struct pool *pool, struct dm_bio_prison_cell *cell) { struct bio *bio; struct bio_list bios; bio_list_init(&bios); - dm_cell_release(cell, &bios); + cell_release(pool, cell, &bios); while ((bio = bio_list_pop(&bios))) retry_on_resume(bio); @@ -941,7 +990,7 @@ static void process_discard(struct thin_c *tc, struct bio *bio) struct dm_thin_new_mapping *m; build_virtual_key(tc->td, block, &key); - if (dm_bio_detain(tc->pool->prison, &key, bio, &cell)) + if (bio_detain(tc->pool, &key, bio, &cell)) return; r = dm_thin_find_block(tc->td, block, 1, &lookup_result); @@ -953,7 +1002,7 @@ static void process_discard(struct thin_c *tc, struct bio *bio) * on this block. */ build_data_key(tc->td, lookup_result.block, &key2); - if (dm_bio_detain(tc->pool->prison, &key2, bio, &cell2)) { + if (bio_detain(tc->pool, &key2, bio, &cell2)) { cell_defer_no_holder(tc, cell); break; } @@ -1029,13 +1078,13 @@ static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block, break; case -ENOSPC: - no_space(cell); + no_space(tc->pool, cell); break; default: DMERR_LIMIT("%s: alloc_data_block() failed: error = %d", __func__, r); - dm_cell_error(cell); + cell_error(tc->pool, cell); break; } } @@ -1053,7 +1102,7 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio, * of being broken so we have nothing further to do here. */ build_data_key(tc->td, lookup_result->block, &key); - if (dm_bio_detain(pool->prison, &key, bio, &cell)) + if (bio_detain(pool, &key, bio, &cell)) return; if (bio_data_dir(bio) == WRITE && bio->bi_size) @@ -1074,12 +1123,13 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block { int r; dm_block_t data_block; + struct pool *pool = tc->pool; /* * Remap empty bios (flushes) immediately, without provisioning. */ if (!bio->bi_size) { - inc_all_io_entry(tc->pool, bio); + inc_all_io_entry(pool, bio); cell_defer_no_holder(tc, cell); remap_and_issue(tc, bio, 0); @@ -1106,14 +1156,14 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block break; case -ENOSPC: - no_space(cell); + no_space(pool, cell); break; default: DMERR_LIMIT("%s: alloc_data_block() failed: error = %d", __func__, r); - set_pool_mode(tc->pool, PM_READ_ONLY); - dm_cell_error(cell); + set_pool_mode(pool, PM_READ_ONLY); + cell_error(pool, cell); break; } } @@ -1121,6 +1171,7 @@ static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block static void process_bio(struct thin_c *tc, struct bio *bio) { int r; + struct pool *pool = tc->pool; dm_block_t block = get_bio_block(tc, bio); struct dm_bio_prison_cell *cell; struct dm_cell_key key; @@ -1131,7 +1182,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio) * being provisioned so we have nothing further to do here. */ build_virtual_key(tc->td, block, &key); - if (dm_bio_detain(tc->pool->prison, &key, bio, &cell)) + if (bio_detain(pool, &key, bio, &cell)) return; r = dm_thin_find_block(tc->td, block, 1, &lookup_result); @@ -1139,9 +1190,9 @@ static void process_bio(struct thin_c *tc, struct bio *bio) case 0: if (lookup_result.shared) { process_shared_bio(tc, bio, block, &lookup_result); - cell_defer_no_holder(tc, cell); + cell_defer_no_holder(tc, cell); /* FIXME: pass this cell into process_shared? */ } else { - inc_all_io_entry(tc->pool, bio); + inc_all_io_entry(pool, bio); cell_defer_no_holder(tc, cell); remap_and_issue(tc, bio, lookup_result.block); @@ -1150,7 +1201,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio) case -ENODATA: if (bio_data_dir(bio) == READ && tc->origin_dev) { - inc_all_io_entry(tc->pool, bio); + inc_all_io_entry(pool, bio); cell_defer_no_holder(tc, cell); remap_to_origin_and_issue(tc, bio); @@ -1429,11 +1480,11 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio) } build_virtual_key(tc->td, block, &key); - if (dm_bio_detain(tc->pool->prison, &key, bio, &cell1)) + if (bio_detain(tc->pool, &key, bio, &cell1)) return DM_MAPIO_SUBMITTED; build_data_key(tc->td, result.block, &key); - if (dm_bio_detain(tc->pool->prison, &key, bio, &cell2)) { + if (bio_detain(tc->pool, &key, bio, &cell2)) { cell_defer_no_holder(tc, cell1); return DM_MAPIO_SUBMITTED; } -- cgit v1.2.3-59-g8ed1b