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Commit 01b284f9 authored by Arnd Bergmann's avatar Arnd Bergmann
Browse files

blktrace: remove the big kernel lock 



According to Jens, this code does not need the BKL at all,
it is sufficiently serialized by bd_mutex.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
parent 0fc86c7b

kernel/trace/blktrace.c

+3 −11
Original line number Original line Diff line number Diff line
@@ -23,7 +23,6 @@ 
#include <linux/mutex.h>

#include <linux/mutex.h>

#include <linux/slab.h>

#include <linux/slab.h>

#include <linux/debugfs.h>

#include <linux/debugfs.h>

#include <linux/smp_lock.h>

#include <linux/time.h>

#include <linux/time.h>

#include <linux/uaccess.h>

#include <linux/uaccess.h>
@@ -639,7 +638,6 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 
	if (!q)

	if (!q)

		return -ENXIO;

		return -ENXIO;





	lock_kernel();

	mutex_lock(&bdev->bd_mutex);

	mutex_lock(&bdev->bd_mutex);





	switch (cmd) {

	switch (cmd) {
@@ -667,7 +665,6 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg) 
	}

	}





	mutex_unlock(&bdev->bd_mutex);

	mutex_unlock(&bdev->bd_mutex);

	unlock_kernel();

	return ret;

	return ret;

}

}
@@ -1652,10 +1649,9 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 
	struct block_device *bdev;

	struct block_device *bdev;

	ssize_t ret = -ENXIO;

	ssize_t ret = -ENXIO;





	lock_kernel();

	bdev = bdget(part_devt(p));

	bdev = bdget(part_devt(p));

	if (bdev == NULL)

	if (bdev == NULL)

		goto out_unlock_kernel;

		goto out;





	q = blk_trace_get_queue(bdev);

	q = blk_trace_get_queue(bdev);

	if (q == NULL)

	if (q == NULL)
@@ -1683,8 +1679,7 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev, 
	mutex_unlock(&bdev->bd_mutex);

	mutex_unlock(&bdev->bd_mutex);

out_bdput:

out_bdput:

	bdput(bdev);

	bdput(bdev);

out_unlock_kernel:

out:

	unlock_kernel();

	return ret;

	return ret;

}

}
@@ -1714,11 +1709,10 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 




	ret = -ENXIO;

	ret = -ENXIO;





	lock_kernel();

	p = dev_to_part(dev);

	p = dev_to_part(dev);

	bdev = bdget(part_devt(p));

	bdev = bdget(part_devt(p));

	if (bdev == NULL)

	if (bdev == NULL)

		goto out_unlock_kernel;

		goto out;





	q = blk_trace_get_queue(bdev);

	q = blk_trace_get_queue(bdev);

	if (q == NULL)

	if (q == NULL)
@@ -1753,8 +1747,6 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev, 
	mutex_unlock(&bdev->bd_mutex);

	mutex_unlock(&bdev->bd_mutex);

out_bdput:

out_bdput:

	bdput(bdev);

	bdput(bdev);

out_unlock_kernel:

	unlock_kernel();

out:

out:

	return ret ? ret : count;

	return ret ? ret : count;

}

}