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authorLogan Gunthorpe <logang@deltatee.com>2017-06-16 17:48:21 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-07-17 15:42:20 +0200
commit133d55cdb2f1f9e258d6dc34594a6c565f10b3fd (patch)
treeba2d42f4b9faaec0ddd8ffad9d5e73923b8ce39a
parent8a932f73e5b4227bf787474b44dc70b6961d6246 (diff)
downloadlinux-0-day-133d55cdb2f1f9e258d6dc34594a6c565f10b3fd.tar.gz
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>
-rw-r--r--block/genhd.c18
-rw-r--r--fs/proc/devices.c4
-rw-r--r--include/linux/fs.h4
3 files changed, 17 insertions, 9 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 7f520fa..51c1d40 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -242,6 +242,7 @@ EXPORT_SYMBOL_GPL(disk_map_sector_rcu);
* Can be deleted altogether. Later.
*
*/
+#define BLKDEV_MAJOR_HASH_SIZE 255
static struct blk_major_name {
struct blk_major_name *next;
int major;
@@ -259,12 +260,11 @@ void blkdev_show(struct seq_file *seqf, off_t offset)
{
struct blk_major_name *dp;
- if (offset < BLKDEV_MAJOR_HASH_SIZE) {
- mutex_lock(&block_class_lock);
- for (dp = major_names[offset]; dp; dp = dp->next)
+ mutex_lock(&block_class_lock);
+ for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
+ if (dp->major == offset)
seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
- mutex_unlock(&block_class_lock);
- }
+ mutex_unlock(&block_class_lock);
}
#endif /* CONFIG_PROC_FS */
@@ -309,6 +309,14 @@ int register_blkdev(unsigned int major, const char *name)
ret = major;
}
+ if (major >= BLKDEV_MAJOR_MAX) {
+ pr_err("register_blkdev: major requested (%d) is greater than the maximum (%d) for %s\n",
+ major, BLKDEV_MAJOR_MAX, name);
+
+ ret = -EINVAL;
+ goto out;
+ }
+
p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
if (p == NULL) {
ret = -ENOMEM;
diff --git a/fs/proc/devices.c b/fs/proc/devices.c
index d196e22..e570934 100644
--- a/fs/proc/devices.c
+++ b/fs/proc/devices.c
@@ -25,7 +25,7 @@ static int devinfo_show(struct seq_file *f, void *v)
static void *devinfo_start(struct seq_file *f, loff_t *pos)
{
- if (*pos < (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_MAX))
+ if (*pos < (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
return pos;
return NULL;
}
@@ -33,7 +33,7 @@ static void *devinfo_start(struct seq_file *f, loff_t *pos)
static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
{
(*pos)++;
- if (*pos >= (BLKDEV_MAJOR_HASH_SIZE + CHRDEV_MAJOR_MAX))
+ if (*pos >= (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
return NULL;
return pos;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b07433c..570dcc6 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);