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authorMatthias Kaehlcke <matthias.kaehlcke@gmail.com>2007-05-08 00:32:08 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:15 -0700
commit0e82d5b61841f2b9e2d31a4299ce09752c5d3288 (patch)
treeb8d6009112eb44425fca70779f4bc2337e9df6ca
parent6acc369a43ada9b829b3e1e4daef5c8a52a2d39a (diff)
use mutex instead of semaphore for misc char devices
The misc character device driver uses a semaphore as mutex. Use the mutex API instead of the (binary) semaphore. Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/char/misc.c27
1 files changed, 14 insertions, 13 deletions
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 7e975f60692..4e6fb9651a1 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -41,6 +41,7 @@
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/slab.h>
+#include <linux/mutex.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/stat.h>
@@ -53,7 +54,7 @@
* Head entry for the doubly linked miscdevice list
*/
static LIST_HEAD(misc_list);
-static DECLARE_MUTEX(misc_sem);
+static DEFINE_MUTEX(misc_mtx);
/*
* Assigned numbers, used for dynamic minors
@@ -69,7 +70,7 @@ static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
struct miscdevice *p;
loff_t off = 0;
- down(&misc_sem);
+ mutex_lock(&misc_mtx);
list_for_each_entry(p, &misc_list, list) {
if (*pos == off++)
return p;
@@ -89,7 +90,7 @@ static void *misc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
static void misc_seq_stop(struct seq_file *seq, void *v)
{
- up(&misc_sem);
+ mutex_unlock(&misc_mtx);
}
static int misc_seq_show(struct seq_file *seq, void *v)
@@ -129,7 +130,7 @@ static int misc_open(struct inode * inode, struct file * file)
int err = -ENODEV;
const struct file_operations *old_fops, *new_fops = NULL;
- down(&misc_sem);
+ mutex_lock(&misc_mtx);
list_for_each_entry(c, &misc_list, list) {
if (c->minor == minor) {
@@ -139,9 +140,9 @@ static int misc_open(struct inode * inode, struct file * file)
}
if (!new_fops) {
- up(&misc_sem);
+ mutex_unlock(&misc_mtx);
request_module("char-major-%d-%d", MISC_MAJOR, minor);
- down(&misc_sem);
+ mutex_lock(&misc_mtx);
list_for_each_entry(c, &misc_list, list) {
if (c->minor == minor) {
@@ -165,7 +166,7 @@ static int misc_open(struct inode * inode, struct file * file)
}
fops_put(old_fops);
fail:
- up(&misc_sem);
+ mutex_unlock(&misc_mtx);
return err;
}
@@ -201,10 +202,10 @@ int misc_register(struct miscdevice * misc)
INIT_LIST_HEAD(&misc->list);
- down(&misc_sem);
+ mutex_lock(&misc_mtx);
list_for_each_entry(c, &misc_list, list) {
if (c->minor == misc->minor) {
- up(&misc_sem);
+ mutex_unlock(&misc_mtx);
return -EBUSY;
}
}
@@ -215,7 +216,7 @@ int misc_register(struct miscdevice * misc)
if ( (misc_minors[i>>3] & (1 << (i&7))) == 0)
break;
if (i<0) {
- up(&misc_sem);
+ mutex_unlock(&misc_mtx);
return -EBUSY;
}
misc->minor = i;
@@ -238,7 +239,7 @@ int misc_register(struct miscdevice * misc)
*/
list_add(&misc->list, &misc_list);
out:
- up(&misc_sem);
+ mutex_unlock(&misc_mtx);
return err;
}
@@ -259,13 +260,13 @@ int misc_deregister(struct miscdevice * misc)
if (list_empty(&misc->list))
return -EINVAL;
- down(&misc_sem);
+ mutex_lock(&misc_mtx);
list_del(&misc->list);
device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
if (i < DYNAMIC_MINORS && i>0) {
misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
}
- up(&misc_sem);
+ mutex_unlock(&misc_mtx);
return 0;
}