block: always set bdev->bd_part

Till now, bdev->bd_part is set only if the bdev was for parts other
than part0.  This patch makes bdev->bd_part always set so that code
paths don't have to differenciate common handling.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

2 files changed, 32 insertions, 42 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 57d572642854..c3fa19bd64df 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -540,14 +540,6 @@ EXPORT_SYMBOL(bd_release);
  *           /sys/block/sda/holders/dm-0 --> /sys/block/dm-0
  */
 
-static struct kobject *bdev_get_kobj(struct block_device *bdev)
-{
-        if (bdev->bd_contains != bdev)
-                return kobject_get(&part_to_dev(bdev->bd_part)->kobj);
-        else
-                return kobject_get(&disk_to_dev(bdev->bd_disk)->kobj);
-}
-
 static int add_symlink(struct kobject *from, struct kobject *to)
 {
         if (!from || !to)
@@ -596,7 +588,7 @@ static int bd_holder_grab_dirs(struct block_device *bdev,
         if (!bo->hdev)
                 goto fail_put_sdir;
 
-        bo->sdev = bdev_get_kobj(bdev);
+        bo->sdev = kobject_get(&part_to_dev(bdev->bd_part)->kobj);
         if (!bo->sdev)
                 goto fail_put_hdev;
 
@@ -919,7 +911,6 @@ static int __blkdev_put(struct block_device *bdev, int for_part);
 
 static int do_open(struct block_device *bdev, struct file *file, int for_part)
 {
-        struct module *owner = NULL;
         struct gendisk *disk;
         struct hd_struct *part = NULL;
         int ret;
@@ -941,25 +932,27 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
 
         ret = -ENXIO;
         file->f_mapping = bdev->bd_inode->i_mapping;
+
         lock_kernel();
+
         disk = get_gendisk(bdev->bd_dev, &partno);
-        if (!disk) {
-                unlock_kernel();
-                bdput(bdev);
-                return ret;
-        }
-        owner = disk->fops->owner;
+        if (!disk)
+                goto out_unlock_kernel;
+        part = disk_get_part(disk, partno);
+        if (!part)
+                goto out_unlock_kernel;
 
         mutex_lock_nested(&bdev->bd_mutex, for_part);
         if (!bdev->bd_openers) {
                 bdev->bd_disk = disk;
+                bdev->bd_part = part;
                 bdev->bd_contains = bdev;
                 if (!partno) {
                         struct backing_dev_info *bdi;
                         if (disk->fops->open) {
                                 ret = disk->fops->open(bdev->bd_inode, file);
                                 if (ret)
-                                        goto out_first;
+                                        goto out_clear;
                         }
                         if (!bdev->bd_openers) {
                                 bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);
@@ -975,31 +968,32 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
                         whole = bdget_disk(disk, 0);
                         ret = -ENOMEM;
                         if (!whole)
-                                goto out_first;
+                                goto out_clear;
                         BUG_ON(for_part);
                         ret = __blkdev_get(whole, file->f_mode, file->f_flags, 1);
                         if (ret)
-                                goto out_first;
+                                goto out_clear;
                         bdev->bd_contains = whole;
-                        part = disk_get_part(disk, partno);
                         bdev->bd_inode->i_data.backing_dev_info =
                            whole->bd_inode->i_data.backing_dev_info;
                         if (!(disk->flags & GENHD_FL_UP) ||
                             !part || !part->nr_sects) {
                                 ret = -ENXIO;
-                                goto out_first;
+                                goto out_clear;
                         }
-                        bdev->bd_part = part;
                         bd_set_size(bdev, (loff_t)part->nr_sects << 9);
                 }
         } else {
+                disk_put_part(part);
                 put_disk(disk);
-                module_put(owner);
+                module_put(disk->fops->owner);
+                part = NULL;
+                disk = NULL;
                 if (bdev->bd_contains == bdev) {
                         if (bdev->bd_disk->fops->open) {
                                 ret = bdev->bd_disk->fops->open(bdev->bd_inode, file);
                                 if (ret)
-                                        goto out;
+                                        goto out_unlock_bdev;
                         }
                         if (bdev->bd_invalidated)
                                 rescan_partitions(bdev->bd_disk, bdev);
@@ -1012,20 +1006,24 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
         unlock_kernel();
         return 0;
 
-out_first:
+ out_clear:
         bdev->bd_disk = NULL;
+        bdev->bd_part = NULL;
         bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
         if (bdev != bdev->bd_contains)
                 __blkdev_put(bdev->bd_contains, 1);
         bdev->bd_contains = NULL;
-        put_disk(disk);
-        disk_put_part(part);
-        module_put(owner);
-out:
+ out_unlock_bdev:
         mutex_unlock(&bdev->bd_mutex);
+ out_unlock_kernel:
         unlock_kernel();
-        if (ret)
-                bdput(bdev);
+
+        disk_put_part(part);
+        if (disk)
+                module_put(disk->fops->owner);
+        put_disk(disk);
+        bdput(bdev);
+
         return ret;
 }
 
@@ -1110,11 +1108,8 @@ static int __blkdev_put(struct block_device *bdev, int for_part)
 
                 put_disk(disk);
                 module_put(owner);
-
-                if (bdev->bd_contains != bdev) {
-                        disk_put_part(bdev->bd_part);
-                        bdev->bd_part = NULL;
-                }
+                disk_put_part(bdev->bd_part);
+                bdev->bd_part = NULL;
                 bdev->bd_disk = NULL;
                 bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
                 if (bdev != bdev->bd_contains)
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index f0f604950ff4..87298c0fc8ce 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -134,12 +134,7 @@ char *disk_name(struct gendisk *hd, int partno, char *buf)
 
 const char *bdevname(struct block_device *bdev, char *buf)
 {
-        int partno = 0;
-
-        if (bdev->bd_part)
-                partno = bdev->bd_part->partno;
-
-        return disk_name(bdev->bd_disk, partno, buf);
+        return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
 }
 
 EXPORT_SYMBOL(bdevname);