Merge tag 'mac80211-next-for-john-2014-11-04' of git://git.kernel.org/pub/scm/linux...
[cascardo/linux.git] / drivers / md / dm.c
index 32b958d..58f3927 100644 (file)
@@ -142,6 +142,9 @@ struct mapped_device {
         */
        struct dm_table *map;
 
+       struct list_head table_devices;
+       struct mutex table_devices_lock;
+
        unsigned long flags;
 
        struct request_queue *queue;
@@ -212,6 +215,12 @@ struct dm_md_mempools {
        struct bio_set *bs;
 };
 
+struct table_device {
+       struct list_head list;
+       atomic_t count;
+       struct dm_dev dm_dev;
+};
+
 #define RESERVED_BIO_BASED_IOS         16
 #define RESERVED_REQUEST_BASED_IOS     256
 #define RESERVED_MAX_IOS               1024
@@ -669,6 +678,120 @@ static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
        rcu_read_unlock();
 }
 
+/*
+ * Open a table device so we can use it as a map destination.
+ */
+static int open_table_device(struct table_device *td, dev_t dev,
+                            struct mapped_device *md)
+{
+       static char *_claim_ptr = "I belong to device-mapper";
+       struct block_device *bdev;
+
+       int r;
+
+       BUG_ON(td->dm_dev.bdev);
+
+       bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _claim_ptr);
+       if (IS_ERR(bdev))
+               return PTR_ERR(bdev);
+
+       r = bd_link_disk_holder(bdev, dm_disk(md));
+       if (r) {
+               blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL);
+               return r;
+       }
+
+       td->dm_dev.bdev = bdev;
+       return 0;
+}
+
+/*
+ * Close a table device that we've been using.
+ */
+static void close_table_device(struct table_device *td, struct mapped_device *md)
+{
+       if (!td->dm_dev.bdev)
+               return;
+
+       bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
+       blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
+       td->dm_dev.bdev = NULL;
+}
+
+static struct table_device *find_table_device(struct list_head *l, dev_t dev,
+                                             fmode_t mode) {
+       struct table_device *td;
+
+       list_for_each_entry(td, l, list)
+               if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
+                       return td;
+
+       return NULL;
+}
+
+int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
+                       struct dm_dev **result) {
+       int r;
+       struct table_device *td;
+
+       mutex_lock(&md->table_devices_lock);
+       td = find_table_device(&md->table_devices, dev, mode);
+       if (!td) {
+               td = kmalloc(sizeof(*td), GFP_KERNEL);
+               if (!td) {
+                       mutex_unlock(&md->table_devices_lock);
+                       return -ENOMEM;
+               }
+
+               td->dm_dev.mode = mode;
+               td->dm_dev.bdev = NULL;
+
+               if ((r = open_table_device(td, dev, md))) {
+                       mutex_unlock(&md->table_devices_lock);
+                       kfree(td);
+                       return r;
+               }
+
+               format_dev_t(td->dm_dev.name, dev);
+
+               atomic_set(&td->count, 0);
+               list_add(&td->list, &md->table_devices);
+       }
+       atomic_inc(&td->count);
+       mutex_unlock(&md->table_devices_lock);
+
+       *result = &td->dm_dev;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(dm_get_table_device);
+
+void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
+{
+       struct table_device *td = container_of(d, struct table_device, dm_dev);
+
+       mutex_lock(&md->table_devices_lock);
+       if (atomic_dec_and_test(&td->count)) {
+               close_table_device(td, md);
+               list_del(&td->list);
+               kfree(td);
+       }
+       mutex_unlock(&md->table_devices_lock);
+}
+EXPORT_SYMBOL(dm_put_table_device);
+
+static void free_table_devices(struct list_head *devices)
+{
+       struct list_head *tmp, *next;
+
+       list_for_each_safe(tmp, next, devices) {
+               struct table_device *td = list_entry(tmp, struct table_device, list);
+
+               DMWARN("dm_destroy: %s still exists with %d references",
+                      td->dm_dev.name, atomic_read(&td->count));
+               kfree(td);
+       }
+}
+
 /*
  * Get the geometry associated with a dm device
  */
@@ -1249,13 +1372,13 @@ static void clone_bio(struct dm_target_io *tio, struct bio *bio,
 }
 
 static struct dm_target_io *alloc_tio(struct clone_info *ci,
-                                     struct dm_target *ti, int nr_iovecs,
+                                     struct dm_target *ti,
                                      unsigned target_bio_nr)
 {
        struct dm_target_io *tio;
        struct bio *clone;
 
-       clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, ci->md->bs);
+       clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs);
        tio = container_of(clone, struct dm_target_io, clone);
 
        tio->io = ci->io;
@@ -1269,17 +1392,12 @@ static void __clone_and_map_simple_bio(struct clone_info *ci,
                                       struct dm_target *ti,
                                       unsigned target_bio_nr, unsigned *len)
 {
-       struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, target_bio_nr);
+       struct dm_target_io *tio = alloc_tio(ci, ti, target_bio_nr);
        struct bio *clone = &tio->clone;
 
        tio->len_ptr = len;
 
-       /*
-        * Discard requests require the bio's inline iovecs be initialized.
-        * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
-        * and discard, so no need for concern about wasted bvec allocations.
-        */
-        __bio_clone_fast(clone, ci->bio);
+       __bio_clone_fast(clone, ci->bio);
        if (len)
                bio_setup_sector(clone, ci->sector, *len);
 
@@ -1322,7 +1440,7 @@ static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti
                num_target_bios = ti->num_write_bios(ti, bio);
 
        for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
-               tio = alloc_tio(ci, ti, 0, target_bio_nr);
+               tio = alloc_tio(ci, ti, target_bio_nr);
                tio->len_ptr = len;
                clone_bio(tio, bio, sector, *len);
                __map_bio(tio);
@@ -1949,12 +2067,14 @@ static struct mapped_device *alloc_dev(int minor)
        md->type = DM_TYPE_NONE;
        mutex_init(&md->suspend_lock);
        mutex_init(&md->type_lock);
+       mutex_init(&md->table_devices_lock);
        spin_lock_init(&md->deferred_lock);
        atomic_set(&md->holders, 1);
        atomic_set(&md->open_count, 0);
        atomic_set(&md->event_nr, 0);
        atomic_set(&md->uevent_seq, 0);
        INIT_LIST_HEAD(&md->uevent_list);
+       INIT_LIST_HEAD(&md->table_devices);
        spin_lock_init(&md->uevent_lock);
 
        md->queue = blk_alloc_queue(GFP_KERNEL);
@@ -2040,6 +2160,7 @@ static void free_dev(struct mapped_device *md)
        blk_integrity_unregister(md->disk);
        del_gendisk(md->disk);
        cleanup_srcu_struct(&md->io_barrier);
+       free_table_devices(&md->table_devices);
        free_minor(minor);
 
        spin_lock(&_minor_lock);
@@ -2900,7 +3021,7 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, u
        if (!pools->io_pool)
                goto out;
 
-       pools->bs = bioset_create(pool_size, front_pad);
+       pools->bs = bioset_create_nobvec(pool_size, front_pad);
        if (!pools->bs)
                goto out;