swsusp: use GFP_KERNEL for creating basic data structures

Make swsusp call create_basic_memory_bitmaps() before processes are frozen, so
that GFP_KERNEL allocations can be made in it.  Additionally, ensure that the
swsusp's userland interface won't be used while either pm_suspend_disk() or
software_resume() is being executed.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 26 insertions, 11 deletions

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 403bc3722fee..e518379b667a 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -130,28 +130,33 @@ int pm_suspend_disk(void)
 {
         int error;
 
+        /* The snapshot device should not be opened while we're running */
+        if (!atomic_add_unless(&snapshot_device_available, -1, 0))
+                return -EBUSY;
+
+        /* Allocate memory management structures */
+        error = create_basic_memory_bitmaps();
+        if (error)
+                goto Exit;
+
         error = prepare_processes();
         if (error)
-                return error;
+                goto Finish;
 
         if (pm_disk_mode == PM_DISK_TESTPROC) {
                 printk("swsusp debug: Waiting for 5 seconds.\n");
                 mdelay(5000);
                 goto Thaw;
         }
-        /* Allocate memory management structures */
-        error = create_basic_memory_bitmaps();
-        if (error)
-                goto Thaw;
 
         /* Free memory before shutting down devices. */
         error = swsusp_shrink_memory();
         if (error)
-                goto Finish;
+                goto Thaw;
 
         error = platform_prepare();
         if (error)
-                goto Finish;
+                goto Thaw;
 
         suspend_console();
         error = device_suspend(PMSG_FREEZE);
@@ -186,7 +191,7 @@ int pm_suspend_disk(void)
                         power_down();
                 else {
                         swsusp_free();
-                        goto Finish;
+                        goto Thaw;
                 }
         } else {
                 pr_debug("PM: Image restored successfully.\n");
@@ -199,10 +204,12 @@ int pm_suspend_disk(void)
         platform_finish();
         device_resume();
         resume_console();
- Finish:
-        free_basic_memory_bitmaps();
  Thaw:
         unprepare_processes();
+ Finish:
+        free_basic_memory_bitmaps();
+ Exit:
+        atomic_inc(&snapshot_device_available);
         return error;
 }
 
@@ -250,9 +257,15 @@ static int software_resume(void)
         if (error)
                 goto Unlock;
 
+        /* The snapshot device should not be opened while we're running */
+        if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
+                error = -EBUSY;
+                goto Unlock;
+        }
+
         error = create_basic_memory_bitmaps();
         if (error)
-                goto Unlock;
+                goto Finish;
 
         pr_debug("PM: Preparing processes for restore.\n");
         error = prepare_processes();
@@ -290,6 +303,8 @@ static int software_resume(void)
         unprepare_processes();
  Done:
         free_basic_memory_bitmaps();
+ Finish:
+        atomic_inc(&snapshot_device_available);
         /* For success case, the suspend path will release the lock */
  Unlock:
         mutex_unlock(&pm_mutex);