uml: kill big kernel lock
Three uml device drivers still use the big kernel lock,
but all of them can be safely converted to using
a per-driver mutex instead. Most likely this is not
even necessary, so after further review these can
and should be removed as well.
The exec system call no longer requires the BKL either,
so remove it from there, too.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: user-mode-linux-devel@lists.sourceforge.net
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 1bcd208..0c05360 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -33,7 +33,7 @@
#include "linux/mm.h"
#include "linux/slab.h"
#include "linux/vmalloc.h"
-#include "linux/smp_lock.h"
+#include "linux/mutex.h"
#include "linux/blkpg.h"
#include "linux/genhd.h"
#include "linux/spinlock.h"
@@ -100,6 +100,7 @@
#define DRIVER_NAME "uml-blkdev"
static DEFINE_MUTEX(ubd_lock);
+static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
static int ubd_open(struct block_device *bdev, fmode_t mode);
static int ubd_release(struct gendisk *disk, fmode_t mode);
@@ -1099,7 +1100,7 @@
struct ubd *ubd_dev = disk->private_data;
int err = 0;
- lock_kernel();
+ mutex_lock(&ubd_mutex);
if(ubd_dev->count == 0){
err = ubd_open_dev(ubd_dev);
if(err){
@@ -1118,7 +1119,7 @@
err = -EROFS;
}*/
out:
- unlock_kernel();
+ mutex_unlock(&ubd_mutex);
return err;
}
@@ -1126,10 +1127,10 @@
{
struct ubd *ubd_dev = disk->private_data;
- lock_kernel();
+ mutex_lock(&ubd_mutex);
if(--ubd_dev->count == 0)
ubd_close_dev(ubd_dev);
- unlock_kernel();
+ mutex_unlock(&ubd_mutex);
return 0;
}