PM / Hibernate: Fix blkdev refleaks

While cruising through the swsusp code I found few blkdev reference
leaks of resume_bdev.

swsusp_read: remove blkdev_put altogether. Some fail paths do
             not do that.
swsusp_check: make sure we always put a reference on fail paths
software_resume: all fail paths between swsusp_check and swsusp_read
                 omit swsusp_close. Add it in those cases. And since
                 swsusp_read doesn't drop the reference anymore, do
                 it here unconditionally.

[rjw: Fixed a small coding style issue.]

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

2 files changed, 12 insertions, 7 deletions

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 04b3a83d686f..04a9e90d248f 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -693,21 +693,22 @@ static int software_resume(void)
         /* The snapshot device should not be opened while we're running */
         if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
                 error = -EBUSY;
+                swsusp_close(FMODE_READ);
                 goto Unlock;
         }
 
         pm_prepare_console();
         error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
         if (error)
-                goto Finish;
+                goto close_finish;
 
         error = usermodehelper_disable();
         if (error)
-                goto Finish;
+                goto close_finish;
 
         error = create_basic_memory_bitmaps();
         if (error)
-                goto Finish;
+                goto close_finish;
 
         pr_debug("PM: Preparing processes for restore.\n");
         error = prepare_processes();
@@ -719,6 +720,7 @@ static int software_resume(void)
         pr_debug("PM: Reading hibernation image.\n");
 
         error = swsusp_read(&flags);
+        swsusp_close(FMODE_READ);
         if (!error)
                 hibernation_restore(flags & SF_PLATFORM_MODE);
 
@@ -737,6 +739,9 @@ static int software_resume(void)
         mutex_unlock(&pm_mutex);
         pr_debug("PM: Resume from disk failed.\n");
         return error;
+close_finish:
+        swsusp_close(FMODE_READ);
+        goto Finish;
 }
 
 late_initcall(software_resume);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index b101cdc4df3f..a4388624ed98 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -572,8 +572,6 @@ int swsusp_read(unsigned int *flags_p)
                 error = load_image(&handle, &snapshot, header->pages - 1);
         release_swap_reader(&handle);
 
-        blkdev_put(resume_bdev, FMODE_READ);
-
         if (!error)
                 pr_debug("PM: Image successfully loaded\n");
         else
@@ -596,7 +594,7 @@ int swsusp_check(void)
                 error = bio_read_page(swsusp_resume_block,
                                         swsusp_header, NULL);
                 if (error)
-                        return error;
+                        goto put;
 
                 if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
                         memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
@@ -604,8 +602,10 @@ int swsusp_check(void)
                         error = bio_write_page(swsusp_resume_block,
                                                 swsusp_header, NULL);
                 } else {
-                        return -EINVAL;
+                        error = -EINVAL;
                 }
+
+put:
                 if (error)
                         blkdev_put(resume_bdev, FMODE_READ);
                 else