block: order /proc/devices by major number

Presently, the order of the block devices listed in /proc/devices is not
entirely sequential. If a block device has a major number greater than
BLKDEV_MAJOR_HASH_SIZE (255), it will be ordered as if its major were
module 255. For example, 511 appears after 1.

This patch cleans that up and prints each major number in the correct
order, regardless of where they are stored in the hash table.

In order to do this, we introduce BLKDEV_MAJOR_MAX as an artificial
limit (chosen to be 512). It will then print all devices in major
order number from 0 to the maximum.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index b07433c335ca..570dcc61fda6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2503,14 +2503,14 @@ static inline void unregister_chrdev(unsigned int major, const char *name)
 #define BDEVT_SIZE      10      /* Largest string for MAJ:MIN for blkdev */
 
 #ifdef CONFIG_BLOCK
-#define BLKDEV_MAJOR_HASH_SIZE  255
+#define BLKDEV_MAJOR_MAX        512
 extern const char *__bdevname(dev_t, char *buffer);
 extern const char *bdevname(struct block_device *bdev, char *buffer);
 extern struct block_device *lookup_bdev(const char *);
 extern void blkdev_show(struct seq_file *,off_t);
 
 #else
-#define BLKDEV_MAJOR_HASH_SIZE  0
+#define BLKDEV_MAJOR_MAX        0
 #endif
 
 extern void init_special_inode(struct inode *, umode_t, dev_t);