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

1 files changed, 7 insertions, 5 deletions

diff --git a/arch/um/drivers/hostaudio_kern.c b/arch/um/drivers/hostaudio_kern.c
index 0c46e398cd8f..d92ff6d60297 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 @@ MODULE_PARM_DESC(mixer, MIXER_HELP);
 
 #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 @@ static int hostaudio_open(struct inode *inode, struct file *file)
                 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 @@ static int hostmixer_open_mixdev(struct inode *inode, struct file *file)
                 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) {