diff options
| -rw-r--r-- | drivers/md/dm-ioctl.c | 10 | ||||
| -rw-r--r-- | drivers/md/dm-table.c | 28 | ||||
| -rw-r--r-- | drivers/md/dm.c | 14 | ||||
| -rw-r--r-- | drivers/md/dm.h | 1 |
4 files changed, 33 insertions, 20 deletions
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 8da7a017b4e..54d0588fc1f 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -233,7 +233,7 @@ static void __hash_remove(struct hash_cell *hc) } if (hc->new_map) - dm_table_put(hc->new_map); + dm_table_destroy(hc->new_map); dm_put(hc->md); free_cell(hc); } @@ -827,8 +827,8 @@ static int do_resume(struct dm_ioctl *param) r = dm_swap_table(md, new_map); if (r) { + dm_table_destroy(new_map); dm_put(md); - dm_table_put(new_map); return r; } @@ -836,8 +836,6 @@ static int do_resume(struct dm_ioctl *param) set_disk_ro(dm_disk(md), 0); else set_disk_ro(dm_disk(md), 1); - - dm_table_put(new_map); } if (dm_suspended(md)) @@ -1080,7 +1078,7 @@ static int table_load(struct dm_ioctl *param, size_t param_size) } if (hc->new_map) - dm_table_put(hc->new_map); + dm_table_destroy(hc->new_map); hc->new_map = t; up_write(&_hash_lock); @@ -1109,7 +1107,7 @@ static int table_clear(struct dm_ioctl *param, size_t param_size) } if (hc->new_map) { - dm_table_put(hc->new_map); + dm_table_destroy(hc->new_map); hc->new_map = NULL; } diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index ebaaf72cd82..2fd66c30f7f 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1,6 +1,6 @@ /* * Copyright (C) 2001 Sistina Software (UK) Limited. - * Copyright (C) 2004 Red Hat, Inc. All rights reserved. + * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ @@ -15,6 +15,7 @@ #include <linux/slab.h> #include <linux/interrupt.h> #include <linux/mutex.h> +#include <linux/delay.h> #include <asm/atomic.h> #define DM_MSG_PREFIX "table" @@ -24,6 +25,19 @@ #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t)) #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1) +/* + * The table has always exactly one reference from either mapped_device->map + * or hash_cell->new_map. This reference is not counted in table->holders. + * A pair of dm_create_table/dm_destroy_table functions is used for table + * creation/destruction. + * + * Temporary references from the other code increase table->holders. A pair + * of dm_table_get/dm_table_put functions is used to manipulate it. + * + * When the table is about to be destroyed, we wait for table->holders to + * drop to zero. + */ + struct dm_table { struct mapped_device *md; atomic_t holders; @@ -228,7 +242,7 @@ int dm_table_create(struct dm_table **result, fmode_t mode, return -ENOMEM; INIT_LIST_HEAD(&t->devices); - atomic_set(&t->holders, 1); + atomic_set(&t->holders, 0); t->barriers_supported = 1; if (!num_targets) @@ -259,10 +273,14 @@ static void free_devices(struct list_head *devices) } } -static void table_destroy(struct dm_table *t) +void dm_table_destroy(struct dm_table *t) { unsigned int i; + while (atomic_read(&t->holders)) + msleep(1); + smp_mb(); + /* free the indexes (see dm_table_complete) */ if (t->depth >= 2) vfree(t->index[t->depth - 2]); @@ -300,8 +318,8 @@ void dm_table_put(struct dm_table *t) if (!t) return; - if (atomic_dec_and_test(&t->holders)) - table_destroy(t); + smp_mb__before_atomic_dec(); + atomic_dec(&t->holders); } /* diff --git a/drivers/md/dm.c b/drivers/md/dm.c index dd953b189f4..9f9aa64f733 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -977,8 +977,6 @@ static int dm_any_congested(void *congested_data, int bdi_bits) struct mapped_device *md = congested_data; struct dm_table *map; - atomic_inc(&md->pending); - if (!test_bit(DMF_BLOCK_IO, &md->flags)) { map = dm_get_table(md); if (map) { @@ -987,10 +985,6 @@ static int dm_any_congested(void *congested_data, int bdi_bits) } } - if (!atomic_dec_return(&md->pending)) - /* nudge anyone waiting on suspend queue */ - wake_up(&md->wait); - return r; } @@ -1250,10 +1244,12 @@ static int __bind(struct mapped_device *md, struct dm_table *t) if (md->suspended_bdev) __set_size(md, size); - if (size == 0) + + if (!size) { + dm_table_destroy(t); return 0; + } - dm_table_get(t); dm_table_event_callback(t, event_callback, md); write_lock(&md->map_lock); @@ -1275,7 +1271,7 @@ static void __unbind(struct mapped_device *md) write_lock(&md->map_lock); md->map = NULL; write_unlock(&md->map_lock); - dm_table_put(map); + dm_table_destroy(map); } /* diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 5b5d08ba9e9..bbbe9110f3b 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -36,6 +36,7 @@ struct dm_table; /*----------------------------------------------------------------- * Internal table functions. *---------------------------------------------------------------*/ +void dm_table_destroy(struct dm_table *t); void dm_table_event_callback(struct dm_table *t, void (*fn)(void *), void *context); struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index); |