diff options
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r-- | drivers/md/dm.c | 77 |
1 files changed, 70 insertions, 7 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index ef7bf1dd6900..c5522551122f 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -21,6 +21,7 @@ #include <linux/delay.h> #include <linux/wait.h> #include <linux/pr.h> +#include <linux/vmalloc.h> #define DM_MSG_PREFIX "core" @@ -972,10 +973,64 @@ void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors) } EXPORT_SYMBOL_GPL(dm_accept_partial_bio); +/* + * Flush current->bio_list when the target map method blocks. + * This fixes deadlocks in snapshot and possibly in other targets. + */ +struct dm_offload { + struct blk_plug plug; + struct blk_plug_cb cb; +}; + +static void flush_current_bio_list(struct blk_plug_cb *cb, bool from_schedule) +{ + struct dm_offload *o = container_of(cb, struct dm_offload, cb); + struct bio_list list; + struct bio *bio; + int i; + + INIT_LIST_HEAD(&o->cb.list); + + if (unlikely(!current->bio_list)) + return; + + for (i = 0; i < 2; i++) { + list = current->bio_list[i]; + bio_list_init(¤t->bio_list[i]); + + while ((bio = bio_list_pop(&list))) { + struct bio_set *bs = bio->bi_pool; + if (unlikely(!bs) || bs == fs_bio_set) { + bio_list_add(¤t->bio_list[i], bio); + continue; + } + + spin_lock(&bs->rescue_lock); + bio_list_add(&bs->rescue_list, bio); + queue_work(bs->rescue_workqueue, &bs->rescue_work); + spin_unlock(&bs->rescue_lock); + } + } +} + +static void dm_offload_start(struct dm_offload *o) +{ + blk_start_plug(&o->plug); + o->cb.callback = flush_current_bio_list; + list_add(&o->cb.list, ¤t->plug->cb_list); +} + +static void dm_offload_end(struct dm_offload *o) +{ + list_del(&o->cb.list); + blk_finish_plug(&o->plug); +} + static void __map_bio(struct dm_target_io *tio) { int r; sector_t sector; + struct dm_offload o; struct bio *clone = &tio->clone; struct dm_target *ti = tio->ti; @@ -988,7 +1043,11 @@ static void __map_bio(struct dm_target_io *tio) */ atomic_inc(&tio->io->io_count); sector = clone->bi_iter.bi_sector; + + dm_offload_start(&o); r = ti->type->map(ti, clone); + dm_offload_end(&o); + if (r == DM_MAPIO_REMAPPED) { /* the bio has been remapped so dispatch it */ @@ -1453,7 +1512,7 @@ static struct mapped_device *alloc_dev(int minor) struct mapped_device *md; void *old_md; - md = kzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id); + md = vzalloc_node(sizeof(*md), numa_node_id); if (!md) { DMWARN("unable to allocate device, out of memory."); return NULL; @@ -1547,7 +1606,7 @@ bad_io_barrier: bad_minor: module_put(THIS_MODULE); bad_module_get: - kfree(md); + kvfree(md); return NULL; } @@ -1566,7 +1625,7 @@ static void free_dev(struct mapped_device *md) free_minor(minor); module_put(THIS_MODULE); - kfree(md); + kvfree(md); } static void __bind_mempools(struct mapped_device *md, struct dm_table *t) @@ -2456,11 +2515,15 @@ struct mapped_device *dm_get_from_kobject(struct kobject *kobj) md = container_of(kobj, struct mapped_device, kobj_holder.kobj); - if (test_bit(DMF_FREEING, &md->flags) || - dm_deleting_md(md)) - return NULL; - + spin_lock(&_minor_lock); + if (test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) { + md = NULL; + goto out; + } dm_get(md); +out: + spin_unlock(&_minor_lock); + return md; } |