Commit e49fbbbf authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: split block_class_lock 



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

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 62b508f8

block/genhd.c

+15 −14
Original line number Diff line number Diff line
@@ -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 @@ static struct gendisk *lookup_gendisk(dev_t dev, int *partno) 
			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 @@ static struct gendisk *lookup_gendisk(dev_t dev, int *partno) 
			return dev_to_disk(kobj_to_dev(kobj));

		goto retry;

	}

	mutex_unlock(&block_class_lock);

	mutex_unlock(&bdev_map_lock);

	return NULL;

}