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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Tejun Heo 2008-09-03 08:53:37 +02:00 committed by Jens Axboe
parent ac65ece4ee
commit 2ac3cee529
1 changed files with 9 additions and 19 deletions
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28
block/genhd.c
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@ -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;
}