posix clocks: Replace mutex with reader/writer semaphore

[pandora-kernel.git] / kernel / time / posix-clock.c

diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
index 25028dd..c340ca6 100644 (file)
--- a/kernel/time/posix-clock.c
+++ b/kernel/time/posix-clock.c
@@ -19,7 +19,6 @@
  */
 #include <linux/device.h>
 #include <linux/file.h>
-#include <linux/mutex.h>
 #include <linux/posix-clock.h>
 #include <linux/slab.h>
 #include <linux/syscalls.h>
@@ -34,19 +33,19 @@ static struct posix_clock *get_posix_clock(struct file *fp)
 {
        struct posix_clock *clk = fp->private_data;
 
-       mutex_lock(&clk->mutex);
+       down_read(&clk->rwsem);
 
        if (!clk->zombie)
                return clk;
 
-       mutex_unlock(&clk->mutex);
+       up_read(&clk->rwsem);
 
        return NULL;
 }
 
 static void put_posix_clock(struct posix_clock *clk)
 {
-       mutex_unlock(&clk->mutex);
+       up_read(&clk->rwsem);
 }
 
 static ssize_t posix_clock_read(struct file *fp, char __user *buf,
@@ -156,7 +155,7 @@ static int posix_clock_open(struct inode *inode, struct file *fp)
        struct posix_clock *clk =
                container_of(inode->i_cdev, struct posix_clock, cdev);
 
-       mutex_lock(&clk->mutex);
+       down_read(&clk->rwsem);
 
        if (clk->zombie) {
                err = -ENODEV;
@@ -172,7 +171,7 @@ static int posix_clock_open(struct inode *inode, struct file *fp)
                fp->private_data = clk;
        }
 out:
-       mutex_unlock(&clk->mutex);
+       up_read(&clk->rwsem);
        return err;
 }
 
@@ -211,25 +210,20 @@ int posix_clock_register(struct posix_clock *clk, dev_t devid)
        int err;
 
        kref_init(&clk->kref);
-       mutex_init(&clk->mutex);
+       init_rwsem(&clk->rwsem);
 
        cdev_init(&clk->cdev, &posix_clock_file_operations);
        clk->cdev.owner = clk->ops.owner;
        err = cdev_add(&clk->cdev, devid, 1);
-       if (err)
-               goto no_cdev;
 
        return err;
-no_cdev:
-       mutex_destroy(&clk->mutex);
-       return err;
 }
 EXPORT_SYMBOL_GPL(posix_clock_register);
 
 static void delete_clock(struct kref *kref)
 {
        struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
-       mutex_destroy(&clk->mutex);
+
        if (clk->release)
                clk->release(clk);
 }
@@ -238,9 +232,9 @@ void posix_clock_unregister(struct posix_clock *clk)
 {
        cdev_del(&clk->cdev);
 
-       mutex_lock(&clk->mutex);
+       down_write(&clk->rwsem);
        clk->zombie = true;
-       mutex_unlock(&clk->mutex);
+       up_write(&clk->rwsem);
 
        kref_put(&clk->kref, delete_clock);
 }