1 files changed, 45 insertions, 26 deletions

diff --git a/kernel/power/user.c b/kernel/power/user.c
index f5512cb3aa86..a6332a313262 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -23,6 +23,7 @@
 #include <linux/console.h>
 #include <linux/cpu.h>
 #include <linux/freezer.h>
+#include <linux/smp_lock.h>
 
 #include <asm/uaccess.h>
 
@@ -69,16 +70,22 @@ static int snapshot_open(struct inode *inode, struct file *filp)
         struct snapshot_data *data;
         int error;
 
-        if (!atomic_add_unless(&snapshot_device_available, -1, 0))
-                return -EBUSY;
+        mutex_lock(&pm_mutex);
+
+        if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
+                error = -EBUSY;
+                goto Unlock;
+        }
 
         if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
                 atomic_inc(&snapshot_device_available);
-                return -ENOSYS;
+                error = -ENOSYS;
+                goto Unlock;
         }
         if(create_basic_memory_bitmaps()) {
                 atomic_inc(&snapshot_device_available);
-                return -ENOMEM;
+                error = -ENOMEM;
+                goto Unlock;
         }
         nonseekable_open(inode, filp);
         data = &snapshot_state;
@@ -98,33 +105,36 @@ static int snapshot_open(struct inode *inode, struct file *filp)
                 if (error)
                         pm_notifier_call_chain(PM_POST_HIBERNATION);
         }
-        if (error) {
+        if (error)
                 atomic_inc(&snapshot_device_available);
-                return error;
-        }
         data->frozen = 0;
         data->ready = 0;
         data->platform_support = 0;
 
-        return 0;
+ Unlock:
+        mutex_unlock(&pm_mutex);
+
+        return error;
 }
 
 static int snapshot_release(struct inode *inode, struct file *filp)
 {
         struct snapshot_data *data;
 
+        mutex_lock(&pm_mutex);
+
         swsusp_free();
         free_basic_memory_bitmaps();
         data = filp->private_data;
         free_all_swap_pages(data->swap);
-        if (data->frozen) {
-                mutex_lock(&pm_mutex);
+        if (data->frozen)
                 thaw_processes();
-                mutex_unlock(&pm_mutex);
-        }
         pm_notifier_call_chain(data->mode == O_WRONLY ?
                         PM_POST_HIBERNATION : PM_POST_RESTORE);
         atomic_inc(&snapshot_device_available);
+
+        mutex_unlock(&pm_mutex);
+
         return 0;
 }
 
@@ -134,9 +144,13 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf,
         struct snapshot_data *data;
         ssize_t res;
 
+        mutex_lock(&pm_mutex);
+
         data = filp->private_data;
-        if (!data->ready)
-                return -ENODATA;
+        if (!data->ready) {
+                res = -ENODATA;
+                goto Unlock;
+        }
         res = snapshot_read_next(&data->handle, count);
         if (res > 0) {
                 if (copy_to_user(buf, data_of(data->handle), res))
@@ -144,6 +158,10 @@ static ssize_t snapshot_read(struct file *filp, char __user *buf,
                 else
                         *offp = data->handle.offset;
         }
+
+ Unlock:
+        mutex_unlock(&pm_mutex);
+
         return res;
 }
 
@@ -153,6 +171,8 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf,
         struct snapshot_data *data;
         ssize_t res;
 
+        mutex_lock(&pm_mutex);
+
         data = filp->private_data;
         res = snapshot_write_next(&data->handle, count);
         if (res > 0) {
@@ -161,11 +181,14 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf,
                 else
                         *offp = data->handle.offset;
         }
+
+        mutex_unlock(&pm_mutex);
+
         return res;
 }
 
-static int snapshot_ioctl(struct inode *inode, struct file *filp,
-                          unsigned int cmd, unsigned long arg)
+static long snapshot_ioctl(struct file *filp, unsigned int cmd,
+                                                        unsigned long arg)
 {
         int error = 0;
         struct snapshot_data *data;
@@ -179,6 +202,9 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
+        if (!mutex_trylock(&pm_mutex))
+                return -EBUSY;
+
         data = filp->private_data;
 
         switch (cmd) {
@@ -186,7 +212,6 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
         case SNAPSHOT_FREEZE:
                 if (data->frozen)
                         break;
-                mutex_lock(&pm_mutex);
                 printk("Syncing filesystems ... ");
                 sys_sync();
                 printk("done.\n");
@@ -194,7 +219,6 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                 error = freeze_processes();
                 if (error)
                         thaw_processes();
-                mutex_unlock(&pm_mutex);
                 if (!error)
                         data->frozen = 1;
                 break;
@@ -202,9 +226,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
         case SNAPSHOT_UNFREEZE:
                 if (!data->frozen || data->ready)
                         break;
-                mutex_lock(&pm_mutex);
                 thaw_processes();
-                mutex_unlock(&pm_mutex);
                 data->frozen = 0;
                 break;
 
@@ -307,16 +329,11 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                         error = -EPERM;
                         break;
                 }
-                if (!mutex_trylock(&pm_mutex)) {
-                        error = -EBUSY;
-                        break;
-                }
                 /*
                  * Tasks are frozen and the notifiers have been called with
                  * PM_HIBERNATION_PREPARE
                  */
                 error = suspend_devices_and_enter(PM_SUSPEND_MEM);
-                mutex_unlock(&pm_mutex);
                 break;
 
         case SNAPSHOT_PLATFORM_SUPPORT:
@@ -390,6 +407,8 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
 
         }
 
+        mutex_unlock(&pm_mutex);
+
         return error;
 }
 
@@ -399,7 +418,7 @@ static const struct file_operations snapshot_fops = {
         .read = snapshot_read,
         .write = snapshot_write,
         .llseek = no_llseek,
-        .ioctl = snapshot_ioctl,
+        .unlocked_ioctl = snapshot_ioctl,
 };
 
 static struct miscdevice snapshot_device = {