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458 lines
10 KiB
458 lines
10 KiB
/* |
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* Copyright (C) 2012 Red Hat, Inc. |
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* |
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* This file is released under the GPL. |
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*/ |
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#include "dm.h" |
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#include "dm-bio-prison-v1.h" |
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#include "dm-bio-prison-v2.h" |
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#include <linux/spinlock.h> |
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#include <linux/mempool.h> |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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/*----------------------------------------------------------------*/ |
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#define MIN_CELLS 1024 |
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struct dm_bio_prison { |
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spinlock_t lock; |
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struct rb_root cells; |
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mempool_t cell_pool; |
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}; |
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static struct kmem_cache *_cell_cache; |
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/*----------------------------------------------------------------*/ |
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/* |
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* @nr_cells should be the number of cells you want in use _concurrently_. |
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* Don't confuse it with the number of distinct keys. |
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*/ |
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struct dm_bio_prison *dm_bio_prison_create(void) |
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{ |
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struct dm_bio_prison *prison = kzalloc(sizeof(*prison), GFP_KERNEL); |
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int ret; |
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if (!prison) |
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return NULL; |
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spin_lock_init(&prison->lock); |
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ret = mempool_init_slab_pool(&prison->cell_pool, MIN_CELLS, _cell_cache); |
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if (ret) { |
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kfree(prison); |
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return NULL; |
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} |
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prison->cells = RB_ROOT; |
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return prison; |
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} |
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EXPORT_SYMBOL_GPL(dm_bio_prison_create); |
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void dm_bio_prison_destroy(struct dm_bio_prison *prison) |
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{ |
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mempool_exit(&prison->cell_pool); |
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kfree(prison); |
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} |
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EXPORT_SYMBOL_GPL(dm_bio_prison_destroy); |
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struct dm_bio_prison_cell *dm_bio_prison_alloc_cell(struct dm_bio_prison *prison, gfp_t gfp) |
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{ |
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return mempool_alloc(&prison->cell_pool, gfp); |
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} |
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EXPORT_SYMBOL_GPL(dm_bio_prison_alloc_cell); |
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void dm_bio_prison_free_cell(struct dm_bio_prison *prison, |
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struct dm_bio_prison_cell *cell) |
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{ |
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mempool_free(cell, &prison->cell_pool); |
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} |
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EXPORT_SYMBOL_GPL(dm_bio_prison_free_cell); |
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static void __setup_new_cell(struct dm_cell_key *key, |
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struct bio *holder, |
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struct dm_bio_prison_cell *cell) |
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{ |
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memcpy(&cell->key, key, sizeof(cell->key)); |
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cell->holder = holder; |
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bio_list_init(&cell->bios); |
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} |
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static int cmp_keys(struct dm_cell_key *lhs, |
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struct dm_cell_key *rhs) |
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{ |
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if (lhs->virtual < rhs->virtual) |
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return -1; |
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if (lhs->virtual > rhs->virtual) |
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return 1; |
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if (lhs->dev < rhs->dev) |
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return -1; |
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if (lhs->dev > rhs->dev) |
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return 1; |
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if (lhs->block_end <= rhs->block_begin) |
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return -1; |
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if (lhs->block_begin >= rhs->block_end) |
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return 1; |
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return 0; |
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} |
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static int __bio_detain(struct dm_bio_prison *prison, |
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struct dm_cell_key *key, |
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struct bio *inmate, |
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struct dm_bio_prison_cell *cell_prealloc, |
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struct dm_bio_prison_cell **cell_result) |
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{ |
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int r; |
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struct rb_node **new = &prison->cells.rb_node, *parent = NULL; |
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while (*new) { |
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struct dm_bio_prison_cell *cell = |
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rb_entry(*new, struct dm_bio_prison_cell, node); |
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r = cmp_keys(key, &cell->key); |
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parent = *new; |
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if (r < 0) |
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new = &((*new)->rb_left); |
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else if (r > 0) |
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new = &((*new)->rb_right); |
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else { |
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if (inmate) |
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bio_list_add(&cell->bios, inmate); |
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*cell_result = cell; |
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return 1; |
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} |
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} |
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__setup_new_cell(key, inmate, cell_prealloc); |
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*cell_result = cell_prealloc; |
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rb_link_node(&cell_prealloc->node, parent, new); |
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rb_insert_color(&cell_prealloc->node, &prison->cells); |
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return 0; |
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} |
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static int bio_detain(struct dm_bio_prison *prison, |
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struct dm_cell_key *key, |
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struct bio *inmate, |
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struct dm_bio_prison_cell *cell_prealloc, |
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struct dm_bio_prison_cell **cell_result) |
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{ |
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int r; |
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spin_lock_irq(&prison->lock); |
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r = __bio_detain(prison, key, inmate, cell_prealloc, cell_result); |
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spin_unlock_irq(&prison->lock); |
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return r; |
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} |
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int dm_bio_detain(struct dm_bio_prison *prison, |
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struct dm_cell_key *key, |
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struct bio *inmate, |
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struct dm_bio_prison_cell *cell_prealloc, |
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struct dm_bio_prison_cell **cell_result) |
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{ |
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return bio_detain(prison, key, inmate, cell_prealloc, cell_result); |
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} |
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EXPORT_SYMBOL_GPL(dm_bio_detain); |
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int dm_get_cell(struct dm_bio_prison *prison, |
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struct dm_cell_key *key, |
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struct dm_bio_prison_cell *cell_prealloc, |
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struct dm_bio_prison_cell **cell_result) |
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{ |
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return bio_detain(prison, key, NULL, cell_prealloc, cell_result); |
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} |
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EXPORT_SYMBOL_GPL(dm_get_cell); |
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/* |
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* @inmates must have been initialised prior to this call |
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*/ |
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static void __cell_release(struct dm_bio_prison *prison, |
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struct dm_bio_prison_cell *cell, |
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struct bio_list *inmates) |
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{ |
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rb_erase(&cell->node, &prison->cells); |
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if (inmates) { |
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if (cell->holder) |
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bio_list_add(inmates, cell->holder); |
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bio_list_merge(inmates, &cell->bios); |
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} |
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} |
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void dm_cell_release(struct dm_bio_prison *prison, |
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struct dm_bio_prison_cell *cell, |
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struct bio_list *bios) |
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{ |
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spin_lock_irq(&prison->lock); |
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__cell_release(prison, cell, bios); |
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spin_unlock_irq(&prison->lock); |
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} |
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EXPORT_SYMBOL_GPL(dm_cell_release); |
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/* |
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* Sometimes we don't want the holder, just the additional bios. |
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*/ |
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static void __cell_release_no_holder(struct dm_bio_prison *prison, |
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struct dm_bio_prison_cell *cell, |
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struct bio_list *inmates) |
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{ |
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rb_erase(&cell->node, &prison->cells); |
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bio_list_merge(inmates, &cell->bios); |
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} |
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void dm_cell_release_no_holder(struct dm_bio_prison *prison, |
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struct dm_bio_prison_cell *cell, |
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struct bio_list *inmates) |
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{ |
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unsigned long flags; |
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spin_lock_irqsave(&prison->lock, flags); |
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__cell_release_no_holder(prison, cell, inmates); |
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spin_unlock_irqrestore(&prison->lock, flags); |
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} |
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EXPORT_SYMBOL_GPL(dm_cell_release_no_holder); |
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void dm_cell_error(struct dm_bio_prison *prison, |
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struct dm_bio_prison_cell *cell, blk_status_t error) |
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{ |
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struct bio_list bios; |
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struct bio *bio; |
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bio_list_init(&bios); |
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dm_cell_release(prison, cell, &bios); |
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while ((bio = bio_list_pop(&bios))) { |
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bio->bi_status = error; |
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bio_endio(bio); |
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} |
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} |
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EXPORT_SYMBOL_GPL(dm_cell_error); |
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void dm_cell_visit_release(struct dm_bio_prison *prison, |
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void (*visit_fn)(void *, struct dm_bio_prison_cell *), |
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void *context, |
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struct dm_bio_prison_cell *cell) |
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{ |
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spin_lock_irq(&prison->lock); |
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visit_fn(context, cell); |
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rb_erase(&cell->node, &prison->cells); |
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spin_unlock_irq(&prison->lock); |
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} |
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EXPORT_SYMBOL_GPL(dm_cell_visit_release); |
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static int __promote_or_release(struct dm_bio_prison *prison, |
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struct dm_bio_prison_cell *cell) |
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{ |
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if (bio_list_empty(&cell->bios)) { |
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rb_erase(&cell->node, &prison->cells); |
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return 1; |
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} |
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cell->holder = bio_list_pop(&cell->bios); |
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return 0; |
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} |
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int dm_cell_promote_or_release(struct dm_bio_prison *prison, |
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struct dm_bio_prison_cell *cell) |
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{ |
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int r; |
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spin_lock_irq(&prison->lock); |
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r = __promote_or_release(prison, cell); |
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spin_unlock_irq(&prison->lock); |
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return r; |
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} |
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EXPORT_SYMBOL_GPL(dm_cell_promote_or_release); |
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/*----------------------------------------------------------------*/ |
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#define DEFERRED_SET_SIZE 64 |
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struct dm_deferred_entry { |
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struct dm_deferred_set *ds; |
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unsigned count; |
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struct list_head work_items; |
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}; |
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struct dm_deferred_set { |
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spinlock_t lock; |
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unsigned current_entry; |
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unsigned sweeper; |
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struct dm_deferred_entry entries[DEFERRED_SET_SIZE]; |
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}; |
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struct dm_deferred_set *dm_deferred_set_create(void) |
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{ |
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int i; |
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struct dm_deferred_set *ds; |
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ds = kmalloc(sizeof(*ds), GFP_KERNEL); |
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if (!ds) |
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return NULL; |
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spin_lock_init(&ds->lock); |
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ds->current_entry = 0; |
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ds->sweeper = 0; |
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for (i = 0; i < DEFERRED_SET_SIZE; i++) { |
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ds->entries[i].ds = ds; |
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ds->entries[i].count = 0; |
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INIT_LIST_HEAD(&ds->entries[i].work_items); |
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} |
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return ds; |
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} |
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EXPORT_SYMBOL_GPL(dm_deferred_set_create); |
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void dm_deferred_set_destroy(struct dm_deferred_set *ds) |
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{ |
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kfree(ds); |
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} |
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EXPORT_SYMBOL_GPL(dm_deferred_set_destroy); |
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struct dm_deferred_entry *dm_deferred_entry_inc(struct dm_deferred_set *ds) |
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{ |
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unsigned long flags; |
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struct dm_deferred_entry *entry; |
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spin_lock_irqsave(&ds->lock, flags); |
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entry = ds->entries + ds->current_entry; |
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entry->count++; |
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spin_unlock_irqrestore(&ds->lock, flags); |
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return entry; |
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} |
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EXPORT_SYMBOL_GPL(dm_deferred_entry_inc); |
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static unsigned ds_next(unsigned index) |
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{ |
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return (index + 1) % DEFERRED_SET_SIZE; |
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} |
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static void __sweep(struct dm_deferred_set *ds, struct list_head *head) |
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{ |
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while ((ds->sweeper != ds->current_entry) && |
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!ds->entries[ds->sweeper].count) { |
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list_splice_init(&ds->entries[ds->sweeper].work_items, head); |
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ds->sweeper = ds_next(ds->sweeper); |
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} |
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if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count) |
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list_splice_init(&ds->entries[ds->sweeper].work_items, head); |
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} |
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void dm_deferred_entry_dec(struct dm_deferred_entry *entry, struct list_head *head) |
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{ |
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unsigned long flags; |
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spin_lock_irqsave(&entry->ds->lock, flags); |
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BUG_ON(!entry->count); |
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--entry->count; |
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__sweep(entry->ds, head); |
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spin_unlock_irqrestore(&entry->ds->lock, flags); |
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} |
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EXPORT_SYMBOL_GPL(dm_deferred_entry_dec); |
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/* |
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* Returns 1 if deferred or 0 if no pending items to delay job. |
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*/ |
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int dm_deferred_set_add_work(struct dm_deferred_set *ds, struct list_head *work) |
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{ |
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int r = 1; |
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unsigned next_entry; |
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spin_lock_irq(&ds->lock); |
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if ((ds->sweeper == ds->current_entry) && |
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!ds->entries[ds->current_entry].count) |
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r = 0; |
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else { |
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list_add(work, &ds->entries[ds->current_entry].work_items); |
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next_entry = ds_next(ds->current_entry); |
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if (!ds->entries[next_entry].count) |
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ds->current_entry = next_entry; |
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} |
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spin_unlock_irq(&ds->lock); |
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return r; |
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} |
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EXPORT_SYMBOL_GPL(dm_deferred_set_add_work); |
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/*----------------------------------------------------------------*/ |
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static int __init dm_bio_prison_init_v1(void) |
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{ |
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_cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0); |
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if (!_cell_cache) |
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return -ENOMEM; |
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return 0; |
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} |
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static void dm_bio_prison_exit_v1(void) |
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{ |
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kmem_cache_destroy(_cell_cache); |
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_cell_cache = NULL; |
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} |
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static int (*_inits[])(void) __initdata = { |
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dm_bio_prison_init_v1, |
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dm_bio_prison_init_v2, |
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}; |
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static void (*_exits[])(void) = { |
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dm_bio_prison_exit_v1, |
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dm_bio_prison_exit_v2, |
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}; |
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static int __init dm_bio_prison_init(void) |
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{ |
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const int count = ARRAY_SIZE(_inits); |
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int r, i; |
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for (i = 0; i < count; i++) { |
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r = _inits[i](); |
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if (r) |
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goto bad; |
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} |
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return 0; |
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bad: |
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while (i--) |
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_exits[i](); |
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return r; |
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} |
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static void __exit dm_bio_prison_exit(void) |
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{ |
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int i = ARRAY_SIZE(_exits); |
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while (i--) |
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_exits[i](); |
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} |
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/* |
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* module hooks |
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*/ |
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module_init(dm_bio_prison_init); |
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module_exit(dm_bio_prison_exit); |
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MODULE_DESCRIPTION(DM_NAME " bio prison"); |
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MODULE_AUTHOR("Joe Thornber <[email protected]>"); |
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MODULE_LICENSE("GPL");
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