[PATCH v3 1/3] PM: hibernate: clear in_suspend before freeing the snapshot

[Haowen Tu]

in_suspend indicates that a hibernation snapshot has been created and is
still available.  Keep that state consistent with the lifetime of the
snapshot memory by clearing in_suspend before swsusp_free() releases it.

If image creation fails after in_suspend has been set,
hibernation_snapshot() releases the snapshot memory but currently leaves
in_suspend set.  Preserve its value locally long enough to select the
appropriate device resume message, then clear it before releasing the
snapshot.

Also clear in_suspend before releasing the snapshot after swsusp_write()
returns.

Signed-off-by: Haowen Tu <tuhaowen@xxxxxxxxxxxxx>
---
Changes in v3:
- Split this cleanup from the helper patch.

 kernel/power/hibernate.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index af8d07bafe02..6d3e637c5a02 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -418,6 +418,7 @@ static void shrink_shmem_memory(void)
 int hibernation_snapshot(int platform_mode)
 {
 	pm_message_t msg;
+	bool snapshot_done;
 	int error;
 
 	pm_suspend_clear_flags();
@@ -474,15 +475,18 @@ int hibernation_snapshot(int platform_mode)
 	 * returns here (1) after the image has been created or the
 	 * image creation has failed and (2) after a successful restore.
 	 */
+	snapshot_done = in_suspend;
 
 	/* We may need to release the preallocated image pages here. */
-	if (error || !in_suspend)
+	if (error || !snapshot_done) {
+		in_suspend = 0;
 		swsusp_free();
+	}
 
-	msg = in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
+	msg = snapshot_done ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE;
 	dpm_resume(msg);
 
-	if (error || !in_suspend)
+	if (error || !snapshot_done)
 		pm_restore_gfp_mask();
 
 	console_resume_all();
@@ -865,6 +869,7 @@ int hibernate(void)
 
 		pm_pr_dbg("Writing hibernation image.\n");
 		error = swsusp_write(flags);
+		in_suspend = 0;
 		swsusp_free();
 		if (!error) {
 			if (hibernation_mode == HIBERNATION_TEST_RESUME)
@@ -872,7 +877,6 @@ int hibernate(void)
 			else
 				power_down();
 		}
-		in_suspend = 0;
 		pm_restore_gfp_mask();
 	} else {
 		pm_pr_dbg("Hibernation image restored successfully.\n");
-- 
2.20.1