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/harddog_kern.c b/arch/um/drivers/harddog_kern.c
index cfcac1f..8603627 100644
--- a/arch/um/drivers/harddog_kern.c
+++ b/arch/um/drivers/harddog_kern.c
@@ -42,7 +42,7 @@
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
@@ -50,6 +50,7 @@
MODULE_LICENSE("GPL");
+static DEFINE_MUTEX(harddog_mutex);
static DEFINE_SPINLOCK(lock);
static int timer_alive;
static int harddog_in_fd = -1;
@@ -66,7 +67,7 @@
int err = -EBUSY;
char *sock = NULL;
- lock_kernel();
+ mutex_lock(&harddog_mutex);
spin_lock(&lock);
if(timer_alive)
goto err;
@@ -83,11 +84,11 @@
timer_alive = 1;
spin_unlock(&lock);
- unlock_kernel();
+ mutex_unlock(&harddog_mutex);
return nonseekable_open(inode, file);
err:
spin_unlock(&lock);
- unlock_kernel();
+ mutex_unlock(&harddog_mutex);
return err;
}
@@ -153,9 +154,9 @@
{
long ret;
- lock_kernel();
+ mutex_lock(&harddog_mutex);
ret = harddog_ioctl_unlocked(file, cmd, arg);
- unlock_kernel();
+ mutex_unlock(&harddog_mutex);
return ret;
}
diff --git a/arch/um/drivers/hostaudio_kern.c b/arch/um/drivers/hostaudio_kern.c
index 0c46e39..d92ff6d 100644
--- a/arch/um/drivers/hostaudio_kern.c
+++ b/arch/um/drivers/hostaudio_kern.c
@@ -8,7 +8,7 @@
#include "linux/slab.h"
#include "linux/sound.h"
#include "linux/soundcard.h"
-#include "linux/smp_lock.h"
+#include "linux/mutex.h"
#include "asm/uaccess.h"
#include "init.h"
#include "os.h"
@@ -67,6 +67,8 @@
#endif
+static DEFINE_MUTEX(hostaudio_mutex);
+
/* /dev/dsp file operations */
static ssize_t hostaudio_read(struct file *file, char __user *buffer,
@@ -202,9 +204,9 @@
w = 1;
kparam_block_sysfs_write(dsp);
- lock_kernel();
+ mutex_lock(&hostaudio_mutex);
ret = os_open_file(dsp, of_set_rw(OPENFLAGS(), r, w), 0);
- unlock_kernel();
+ mutex_unlock(&hostaudio_mutex);
kparam_unblock_sysfs_write(dsp);
if (ret < 0) {
@@ -263,9 +265,9 @@
w = 1;
kparam_block_sysfs_write(mixer);
- lock_kernel();
+ mutex_lock(&hostaudio_mutex);
ret = os_open_file(mixer, of_set_rw(OPENFLAGS(), r, w), 0);
- unlock_kernel();
+ mutex_unlock(&hostaudio_mutex);
kparam_unblock_sysfs_write(mixer);
if (ret < 0) {
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 1bcd208c..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;
}
diff --git a/arch/um/kernel/exec.c b/arch/um/kernel/exec.c
index cd145eda..460ce86 100644
--- a/arch/um/kernel/exec.c
+++ b/arch/um/kernel/exec.c
@@ -78,13 +78,11 @@
long error;
char *filename;
- lock_kernel();
filename = getname(file);
error = PTR_ERR(filename);
if (IS_ERR(filename)) goto out;
error = execve1(filename, argv, env);
putname(filename);
out:
- unlock_kernel();
return error;
}
