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: Arnd Bergmann <arnd@arndb.de>
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 959f8d6..5328e87 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -23,7 +23,6 @@
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
-#include <linux/smp_lock.h>
#include <linux/time.h>
#include <linux/uaccess.h>
@@ -639,7 +638,6 @@
if (!q)
return -ENXIO;
- lock_kernel();
mutex_lock(&bdev->bd_mutex);
switch (cmd) {
@@ -667,7 +665,6 @@
}
mutex_unlock(&bdev->bd_mutex);
- unlock_kernel();
return ret;
}
@@ -1652,10 +1649,9 @@
struct block_device *bdev;
ssize_t ret = -ENXIO;
- lock_kernel();
bdev = bdget(part_devt(p));
if (bdev == NULL)
- goto out_unlock_kernel;
+ goto out;
q = blk_trace_get_queue(bdev);
if (q == NULL)
@@ -1683,8 +1679,7 @@
mutex_unlock(&bdev->bd_mutex);
out_bdput:
bdput(bdev);
-out_unlock_kernel:
- unlock_kernel();
+out:
return ret;
}
@@ -1714,11 +1709,10 @@
ret = -ENXIO;
- lock_kernel();
p = dev_to_part(dev);
bdev = bdget(part_devt(p));
if (bdev == NULL)
- goto out_unlock_kernel;
+ goto out;
q = blk_trace_get_queue(bdev);
if (q == NULL)
@@ -1753,8 +1747,6 @@
mutex_unlock(&bdev->bd_mutex);
out_bdput:
bdput(bdev);
-out_unlock_kernel:
- unlock_kernel();
out:
return ret ? ret : count;
}