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Commit 2ac3cee5 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block: don't grab block_class_lock unnecessarily 



block_class_lock protects major_names array and bdev_map and doesn't
have anything to do with block class devices.  Don't grab them while
iterating over block class devices.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent ac65ece4

block/genhd.c

+9 −19
Original line number Diff line number Diff line
@@ -283,9 +283,7 @@ static int printk_partition(struct device *dev, void *data) 
 */

void __init printk_all_partitions(void)

{

	mutex_lock(&block_class_lock);

	class_for_each_device(&block_class, NULL, NULL, printk_partition);

	mutex_unlock(&block_class_lock);

}



#ifdef CONFIG_PROC_FS
@@ -305,17 +303,15 @@ static int find_start(struct device *dev, void *data) 
static void *part_start(struct seq_file *part, loff_t *pos)

{

	struct device *dev;

	loff_t k = *pos;

	loff_t n = *pos;



	if (!k)

	if (!n)

		part->private = (void *)1LU;	/* tell show to print header */



	mutex_lock(&block_class_lock);

	dev = class_find_device(&block_class, NULL, &k, find_start);

	if (dev) {

		put_device(dev);

	dev = class_find_device(&block_class, NULL, &n, find_start);

	if (dev)

		return dev_to_disk(dev);

	}



	return NULL;

}
@@ -341,7 +337,6 @@ static void *part_next(struct seq_file *part, void *v, loff_t *pos) 


static void part_stop(struct seq_file *part, void *v)

{

	mutex_unlock(&block_class_lock);

}



static int show_partition(struct seq_file *part, void *v)
@@ -583,14 +578,12 @@ static struct device_type disk_type = { 
static void *diskstats_start(struct seq_file *part, loff_t *pos)

{

	struct device *dev;

	loff_t k = *pos;

	loff_t n = *pos;



	mutex_lock(&block_class_lock);

	dev = class_find_device(&block_class, NULL, &k, find_start);

	if (dev) {

		put_device(dev);

	dev = class_find_device(&block_class, NULL, &n, find_start);

	if (dev)

		return dev_to_disk(dev);

	}



	return NULL;

}
@@ -610,7 +603,6 @@ static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos) 


static void diskstats_stop(struct seq_file *part, void *v)

{

	mutex_unlock(&block_class_lock);

}



static int diskstats_show(struct seq_file *s, void *v)
@@ -729,7 +721,6 @@ dev_t blk_lookup_devt(const char *name, int part) 
	dev_t devt = MKDEV(0, 0);

	struct find_block find;



	mutex_lock(&block_class_lock);

	find.name = name;

	find.part = part;

	dev = class_find_device(&block_class, NULL, &find, match_id);
@@ -738,7 +729,6 @@ dev_t blk_lookup_devt(const char *name, int part) 
		devt = MKDEV(MAJOR(dev->devt),

			     MINOR(dev->devt) + part);

	}

	mutex_unlock(&block_class_lock);



	return devt;

}