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block: split block_class_lock 

Split the block_class_lock mutex into one each to protect bdev_map
and major_names.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2020-10-29 15:58:26 +01:00 committed by Jens Axboe
parent 62b508f8b6
commit e49fbbbf0a
1 changed files with 15 additions and 14 deletions
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29
block/genhd.c
View File

@ -25,7 +25,6 @@
#include "blk.h"
static DEFINE_MUTEX(block_class_lock);
static struct kobject *block_depr;
struct bdev_map {
@ -37,6 +36,7 @@ struct bdev_map {
int (*lock)(dev_t, void *);
void *data;
} *bdev_map[255];
static DEFINE_MUTEX(bdev_map_lock);
/* for extended dynamic devt allocation, currently only one major is used */
#define NR_EXT_DEVT (1 << MINORBITS)
@ -403,6 +403,7 @@ static struct blk_major_name {
int major;
char name[16];
} *major_names[BLKDEV_MAJOR_HASH_SIZE];
static DEFINE_MUTEX(major_names_lock);
/* index in the above - for now: assume no multimajor ranges */
static inline int major_to_index(unsigned major)
@ -415,11 +416,11 @@ void blkdev_show(struct seq_file *seqf, off_t offset)
{
struct blk_major_name *dp;
mutex_lock(&block_class_lock);
mutex_lock(&major_names_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(&major_names_lock);
}
#endif /* CONFIG_PROC_FS */
@ -448,7 +449,7 @@ int register_blkdev(unsigned int major, const char *name)
struct blk_major_name **n, *p;
int index, ret = 0;
mutex_lock(&block_class_lock);
mutex_lock(&major_names_lock);
/* temporary */
if (major == 0) {
@ -501,7 +502,7 @@ int register_blkdev(unsigned int major, const char *name)
kfree(p);
}
out:
mutex_unlock(&block_class_lock);
mutex_unlock(&major_names_lock);
return ret;
}
@ -513,7 +514,7 @@ void unregister_blkdev(unsigned int major, const char *name)
struct blk_major_name *p = NULL;
int index = major_to_index(major);
mutex_lock(&block_class_lock);
mutex_lock(&major_names_lock);
for (n = &major_names[index]; *n; n = &(*n)->next)
if ((*n)->major == major)
break;
@ -523,7 +524,7 @@ void unregister_blkdev(unsigned int major, const char *name)
p = *n;
*n = p->next;
}
mutex_unlock(&block_class_lock);
mutex_unlock(&major_names_lock);
kfree(p);
}
@ -674,7 +675,7 @@ void blk_register_region(dev_t devt, unsigned long range, struct module *module,
p->data = data;
}
mutex_lock(&block_class_lock);
mutex_lock(&bdev_map_lock);
for (i = 0, p -= n; i < n; i++, p++, index++) {
struct bdev_map **s = &bdev_map[index % 255];
while (*s && (*s)->range < range)
@ -682,7 +683,7 @@ void blk_register_region(dev_t devt, unsigned long range, struct module *module,
p->next = *s;
*s = p;
}
mutex_unlock(&block_class_lock);
mutex_unlock(&bdev_map_lock);
}
EXPORT_SYMBOL(blk_register_region);
@ -693,7 +694,7 @@ void blk_unregister_region(dev_t devt, unsigned long range)
unsigned i;
struct bdev_map *found = NULL;
mutex_lock(&block_class_lock);
mutex_lock(&bdev_map_lock);
for (i = 0; i < min(n, 255u); i++, index++) {
struct bdev_map **s;
for (s = &bdev_map[index % 255]; *s; s = &(*s)->next) {
@ -706,7 +707,7 @@ void blk_unregister_region(dev_t devt, unsigned long range)
}
}
}
mutex_unlock(&block_class_lock);
mutex_unlock(&bdev_map_lock);
kfree(found);
}
EXPORT_SYMBOL(blk_unregister_region);
@ -1037,7 +1038,7 @@ static struct gendisk *lookup_gendisk(dev_t dev, int *partno)
unsigned long best = ~0UL;
retry:
mutex_lock(&block_class_lock);
mutex_lock(&bdev_map_lock);
for (p = bdev_map[MAJOR(dev) % 255]; p; p = p->next) {
struct kobject *(*probe)(dev_t, int *, void *);
struct module *owner;
@ -1058,7 +1059,7 @@ retry:
module_put(owner);
continue;
}
mutex_unlock(&block_class_lock);
mutex_unlock(&bdev_map_lock);
kobj = probe(dev, partno, data);
/* Currently ->owner protects _only_ ->probe() itself. */
module_put(owner);
@ -1066,7 +1067,7 @@ retry:
return dev_to_disk(kobj_to_dev(kobj));
goto retry;
}
mutex_unlock(&block_class_lock);
mutex_unlock(&bdev_map_lock);
return NULL;
}