dm: avoid destroying table in dm_any_congested

[linux-2.6-omap-h63xx.git] / drivers / md / dm.c

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 327de03a5bdfed7f11b0904abb72f3eac65fc92d..c99e4728ff4162ed16c4a7ec99fdc0c27c8cb35f 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -21,7 +21,6 @@
 #include <linux/idr.h>
 #include <linux/hdreg.h>
 #include <linux/blktrace_api.h>
-#include <linux/smp_lock.h>
 
 #define DM_MSG_PREFIX "core"
 
@@ -76,7 +75,6 @@ union map_info *dm_get_mapinfo(struct bio *bio)
  */
 struct dm_wq_req {
        enum {
-               DM_WQ_FLUSH_ALL,
                DM_WQ_FLUSH_DEFERRED,
        } type;
        struct work_struct work;
@@ -151,40 +149,40 @@ static struct kmem_cache *_tio_cache;
 
 static int __init local_init(void)
 {
-       int r;
+       int r = -ENOMEM;
 
        /* allocate a slab for the dm_ios */
        _io_cache = KMEM_CACHE(dm_io, 0);
        if (!_io_cache)
-               return -ENOMEM;
+               return r;
 
        /* allocate a slab for the target ios */
        _tio_cache = KMEM_CACHE(dm_target_io, 0);
-       if (!_tio_cache) {
-               kmem_cache_destroy(_io_cache);
-               return -ENOMEM;
-       }
+       if (!_tio_cache)
+               goto out_free_io_cache;
 
        r = dm_uevent_init();
-       if (r) {
-               kmem_cache_destroy(_tio_cache);
-               kmem_cache_destroy(_io_cache);
-               return r;
-       }
+       if (r)
+               goto out_free_tio_cache;
 
        _major = major;
        r = register_blkdev(_major, _name);
-       if (r < 0) {
-               kmem_cache_destroy(_tio_cache);
-               kmem_cache_destroy(_io_cache);
-               dm_uevent_exit();
-               return r;
-       }
+       if (r < 0)
+               goto out_uevent_exit;
 
        if (!_major)
                _major = r;
 
        return 0;
+
+out_uevent_exit:
+       dm_uevent_exit();
+out_free_tio_cache:
+       kmem_cache_destroy(_tio_cache);
+out_free_io_cache:
+       kmem_cache_destroy(_io_cache);
+
+       return r;
 }
 
 static void local_exit(void)
@@ -249,13 +247,13 @@ static void __exit dm_exit(void)
 /*
  * Block device functions
  */
-static int dm_blk_open(struct inode *inode, struct file *file)
+static int dm_blk_open(struct block_device *bdev, fmode_t mode)
 {
        struct mapped_device *md;
 
        spin_lock(&_minor_lock);
 
-       md = inode->i_bdev->bd_disk->private_data;
+       md = bdev->bd_disk->private_data;
        if (!md)
                goto out;
 
@@ -274,11 +272,9 @@ out:
        return md ? 0 : -ENXIO;
 }
 
-static int dm_blk_close(struct inode *inode, struct file *file)
+static int dm_blk_close(struct gendisk *disk, fmode_t mode)
 {
-       struct mapped_device *md;
-
-       md = inode->i_bdev->bd_disk->private_data;
+       struct mapped_device *md = disk->private_data;
        atomic_dec(&md->open_count);
        dm_put(md);
        return 0;
@@ -315,21 +311,14 @@ static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
        return dm_get_geometry(md, geo);
 }
 
-static int dm_blk_ioctl(struct inode *inode, struct file *file,
+static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
                        unsigned int cmd, unsigned long arg)
 {
-       struct mapped_device *md;
-       struct dm_table *map;
+       struct mapped_device *md = bdev->bd_disk->private_data;
+       struct dm_table *map = dm_get_table(md);
        struct dm_target *tgt;
        int r = -ENOTTY;
 
-       /* We don't really need this lock, but we do need 'inode'. */
-       unlock_kernel();
-
-       md = inode->i_bdev->bd_disk->private_data;
-
-       map = dm_get_table(md);
-
        if (!map || !dm_table_get_size(map))
                goto out;
 
@@ -345,12 +334,11 @@ static int dm_blk_ioctl(struct inode *inode, struct file *file,
        }
 
        if (tgt->type->ioctl)
-               r = tgt->type->ioctl(tgt, inode, file, cmd, arg);
+               r = tgt->type->ioctl(tgt, cmd, arg);
 
 out:
        dm_table_put(map);
 
-       lock_kernel();
        return r;
 }
 
@@ -387,7 +375,7 @@ static void start_io_acct(struct dm_io *io)
        dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending);
 }
 
-static int end_io_acct(struct dm_io *io)
+static void end_io_acct(struct dm_io *io)
 {
        struct mapped_device *md = io->md;
        struct bio *bio = io->bio;
@@ -403,7 +391,9 @@ static int end_io_acct(struct dm_io *io)
        dm_disk(md)->part0.in_flight = pending =
                atomic_dec_return(&md->pending);
 
-       return !pending;
+       /* nudge anyone waiting on suspend queue */
+       if (!pending)
+               wake_up(&md->wait);
 }
 
 /*
@@ -511,9 +501,7 @@ static void dec_pending(struct dm_io *io, int error)
                        spin_unlock_irqrestore(&io->md->pushback_lock, flags);
                }
 
-               if (end_io_acct(io))
-                       /* nudge anyone waiting on suspend queue */
-                       wake_up(&io->md->wait);
+               end_io_acct(io);
 
                if (io->error != DM_ENDIO_REQUEUE) {
                        blk_add_trace_bio(io->md->queue, io->bio,
@@ -669,6 +657,7 @@ static struct bio *split_bvec(struct bio *bio, sector_t sector,
        clone->bi_size = to_bytes(len);
        clone->bi_io_vec->bv_offset = offset;
        clone->bi_io_vec->bv_len = clone->bi_size;
+       clone->bi_flags |= 1 << BIO_CLONED;
 
        return clone;
 }
@@ -948,16 +937,24 @@ static void dm_unplug_all(struct request_queue *q)
 
 static int dm_any_congested(void *congested_data, int bdi_bits)
 {
-       int r;
-       struct mapped_device *md = (struct mapped_device *) congested_data;
-       struct dm_table *map = dm_get_table(md);
+       int r = bdi_bits;
+       struct mapped_device *md = congested_data;
+       struct dm_table *map;
 
-       if (!map || test_bit(DMF_BLOCK_IO, &md->flags))
-               r = bdi_bits;
-       else
-               r = dm_table_any_congested(map, bdi_bits);
+       atomic_inc(&md->pending);
+
+       if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
+               map = dm_get_table(md);
+               if (map) {
+                       r = dm_table_any_congested(map, bdi_bits);
+                       dm_table_put(map);
+               }
+       }
+
+       if (!atomic_dec_return(&md->pending))
+               /* nudge anyone waiting on suspend queue */
+               wake_up(&md->wait);
 
-       dm_table_put(map);
        return r;
 }
 
@@ -1394,9 +1391,6 @@ static void dm_wq_work(struct work_struct *work)
 
        down_write(&md->io_lock);
        switch (req->type) {
-       case DM_WQ_FLUSH_ALL:
-               __merge_pushback_list(md);
-               /* pass through */
        case DM_WQ_FLUSH_DEFERRED:
                __flush_deferred_io(md);
                break;
@@ -1526,7 +1520,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
                if (!md->suspended_bdev) {
                        DMWARN("bdget failed in dm_suspend");
                        r = -ENOMEM;
-                       goto flush_and_out;
+                       goto out;
                }
 
                /*
@@ -1577,14 +1571,6 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
 
        set_bit(DMF_SUSPENDED, &md->flags);
 
-flush_and_out:
-       if (r && noflush)
-               /*
-                * Because there may be already I/Os in the pushback list,
-                * flush them before return.
-                */
-               dm_queue_flush(md, DM_WQ_FLUSH_ALL, NULL);
-
 out:
        if (r && md->suspended_bdev) {
                bdput(md->suspended_bdev);