[PATCH] convert pm_sem to a mutex

The power management semaphore is only used as mutex, so convert it.

[akpm@osdl.org: fix rotten bug]
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 28 insertions, 26 deletions

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 53b3b57c0223..08d9e7aac0f8 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -213,10 +213,10 @@ static int software_resume(void)
 {
         int error;
 
-        down(&pm_sem);
+        mutex_lock(&pm_mutex);
         if (!swsusp_resume_device) {
                 if (!strlen(resume_file)) {
-                        up(&pm_sem);
+                        mutex_unlock(&pm_mutex);
                         return -ENOENT;
                 }
                 swsusp_resume_device = name_to_dev_t(resume_file);
@@ -231,7 +231,7 @@ static int software_resume(void)
                  * FIXME: If noresume is specified, we need to find the partition
                  * and reset it back to normal swap space.
                  */
-                up(&pm_sem);
+                mutex_unlock(&pm_mutex);
                 return 0;
         }
 
@@ -275,7 +275,7 @@ static int software_resume(void)
         unprepare_processes();
  Done:
         /* For success case, the suspend path will release the lock */
-        up(&pm_sem);
+        mutex_unlock(&pm_mutex);
         pr_debug("PM: Resume from disk failed.\n");
         return 0;
 }
@@ -336,7 +336,7 @@ static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
         p = memchr(buf, '\n', n);
         len = p ? p - buf : n;
 
-        down(&pm_sem);
+        mutex_lock(&pm_mutex);
         for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
                 if (!strncmp(buf, pm_disk_modes[i], len)) {
                         mode = i;
@@ -360,7 +360,7 @@ static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
 
         pr_debug("PM: suspend-to-disk mode set to '%s'\n",
                  pm_disk_modes[mode]);
-        up(&pm_sem);
+        mutex_unlock(&pm_mutex);
         return error ? error : n;
 }
 
@@ -385,9 +385,9 @@ static ssize_t resume_store(struct subsystem *subsys, const char *buf, size_t n)
         if (maj != MAJOR(res) || min != MINOR(res))
                 goto out;
 
-        down(&pm_sem);
+        mutex_lock(&pm_mutex);
         swsusp_resume_device = res;
-        up(&pm_sem);
+        mutex_unlock(&pm_mutex);
         printk("Attempting manual resume\n");
         noresume = 0;
         software_resume();
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 6096c71b182b..751157b7897e 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -25,7 +25,7 @@
 /*This is just an arbitrary number */
 #define FREE_PAGE_NUMBER (100)
 
-DECLARE_MUTEX(pm_sem);
+DEFINE_MUTEX(pm_mutex);
 
 struct pm_ops *pm_ops;
 suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
@@ -37,9 +37,9 @@ suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
 
 void pm_set_ops(struct pm_ops * ops)
 {
-        down(&pm_sem);
+        mutex_lock(&pm_mutex);
         pm_ops = ops;
-        up(&pm_sem);
+        mutex_unlock(&pm_mutex);
 }
 
 
@@ -183,7 +183,7 @@ static int enter_state(suspend_state_t state)
 
         if (!valid_state(state))
                 return -ENODEV;
-        if (down_trylock(&pm_sem))
+        if (!mutex_trylock(&pm_mutex))
                 return -EBUSY;
 
         if (state == PM_SUSPEND_DISK) {
@@ -201,7 +201,7 @@ static int enter_state(suspend_state_t state)
         pr_debug("PM: Finishing wakeup.\n");
         suspend_finish(state);
  Unlock:
-        up(&pm_sem);
+        mutex_unlock(&pm_mutex);
         return error;
 }
 
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 3afa5dbe6bc5..eb461b816bf4 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -22,7 +22,9 @@ static inline int pm_suspend_disk(void)
         return -EPERM;
 }
 #endif
-extern struct semaphore pm_sem;
+
+extern struct mutex pm_mutex;
+
 #define power_attr(_name) \
 static struct subsys_attribute _name##_attr = { \
         .attr   = {                             \
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 26c66941c001..905dc269c3fc 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -79,10 +79,10 @@ static int snapshot_release(struct inode *inode, struct file *filp)
         free_all_swap_pages(data->swap, data->bitmap);
         free_bitmap(data->bitmap);
         if (data->frozen) {
-                down(&pm_sem);
+                mutex_lock(&pm_mutex);
                 thaw_processes();
                 enable_nonboot_cpus();
-                up(&pm_sem);
+                mutex_unlock(&pm_mutex);
         }
         atomic_inc(&device_available);
         return 0;
@@ -144,7 +144,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
         case SNAPSHOT_FREEZE:
                 if (data->frozen)
                         break;
-                down(&pm_sem);
+                mutex_lock(&pm_mutex);
                 error = disable_nonboot_cpus();
                 if (!error) {
                         error = freeze_processes();
@@ -154,7 +154,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                                 error = -EBUSY;
                         }
                 }
-                up(&pm_sem);
+                mutex_unlock(&pm_mutex);
                 if (!error)
                         data->frozen = 1;
                 break;
@@ -162,10 +162,10 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
         case SNAPSHOT_UNFREEZE:
                 if (!data->frozen)
                         break;
-                down(&pm_sem);
+                mutex_lock(&pm_mutex);
                 thaw_processes();
                 enable_nonboot_cpus();
-                up(&pm_sem);
+                mutex_unlock(&pm_mutex);
                 data->frozen = 0;
                 break;
 
@@ -174,7 +174,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                         error = -EPERM;
                         break;
                 }
-                down(&pm_sem);
+                mutex_lock(&pm_mutex);
                 /* Free memory before shutting down devices. */
                 error = swsusp_shrink_memory();
                 if (!error) {
@@ -187,7 +187,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                         }
                         resume_console();
                 }
-                up(&pm_sem);
+                mutex_unlock(&pm_mutex);
                 if (!error)
                         error = put_user(in_suspend, (unsigned int __user *)arg);
                 if (!error)
@@ -201,7 +201,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                         error = -EPERM;
                         break;
                 }
-                down(&pm_sem);
+                mutex_lock(&pm_mutex);
                 pm_prepare_console();
                 suspend_console();
                 error = device_suspend(PMSG_PRETHAW);
@@ -211,7 +211,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                 }
                 resume_console();
                 pm_restore_console();
-                up(&pm_sem);
+                mutex_unlock(&pm_mutex);
                 break;
 
         case SNAPSHOT_FREE:
@@ -286,7 +286,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                         break;
                 }
 
-                if (down_trylock(&pm_sem)) {
+                if (!mutex_trylock(&pm_mutex)) {
                         error = -EBUSY;
                         break;
                 }
@@ -314,7 +314,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                         pm_ops->finish(PM_SUSPEND_MEM);
 
 OutS3:
-                up(&pm_sem);
+                mutex_unlock(&pm_mutex);
                 break;
 
         case SNAPSHOT_PMOPS: