From 133d55cdb2f1f9e258d6dc34594a6c565f10b3fd Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Fri, 16 Jun 2017 17:48:21 -0600 Subject: [PATCH] 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 Cc: Jens Axboe Cc: Jeff Layton Cc: "J. Bruce Fields" Signed-off-by: Greg Kroah-Hartman --- block/genhd.c | 18 +++++++++++++----- fs/proc/devices.c | 4 ++-- include/linux/fs.h | 4 ++-- 3 files changed, 17 insertions(+), 9 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index 7f520fa25d16..51c1d407d93c 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 d196e22c4f1c..e5709343feb7 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 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); -- 2.20.1