linux-kernel - [PATCH] PM / Hibernate: Thaw processes in SNAPSHOT_CREATE

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Date:	Thu, 01 Dec 2011 18:45:37 +0530
From:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To:	rjw@...k.pl
Cc:	pavel@....cz, len.brown@...el.com, tj@...nel.org,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: [PATCH] PM / Hibernate: Thaw processes in SNAPSHOT_CREATE_IMAGE ioctl
 error/test paths

Commit 2aede851ddf08666f68ffc17be446420e9d2a056 (PM / Hibernate: Freeze
kernel threads after preallocating memory) moved the freezing of kernel
threads to hibernation_snapshot() function.

So now, if the call to hibernation_snapshot() fails or returns early due
to a successful hibernation test, the caller has to thaw processes to
ensure that the system gets back to its original state.

But in SNAPSHOT_CREATE_IMAGE hibernation ioctl, the caller does not thaw
processes. Fix this issue. But note that if hibernation_snapshot() returned
due to a successful freezer test, we still send the value of 'in_suspend'
(which is now 0) to userspace, because we are not in an error path per-se,
and moreover, the value of in_suspend correctly depicts the situation here.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@...ux.vnet.ibm.com>
---

 kernel/power/hibernate.c |    2 +-
 kernel/power/power.h     |    2 ++
 kernel/power/user.c      |   13 ++++++++++---
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index a6b0503..624538a 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -55,7 +55,7 @@ enum {
 
 static int hibernation_mode = HIBERNATION_SHUTDOWN;
 
-static bool freezer_test_done;
+bool freezer_test_done;
 
 static const struct platform_hibernation_ops *hibernation_ops;
 
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 23a2db1..0c4defe 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -50,6 +50,8 @@ static inline char *check_image_kernel(struct swsusp_info *info)
 #define SPARE_PAGES	((1024 * 1024) >> PAGE_SHIFT)
 
 /* kernel/power/hibernate.c */
+extern bool freezer_test_done;
+
 extern int hibernation_snapshot(int platform_mode);
 extern int hibernation_restore(int platform_mode);
 extern int hibernation_platform_enter(void);
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 6d8f535..b98b7e1 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -283,10 +283,17 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 		}
 		pm_restore_gfp_mask();
 		error = hibernation_snapshot(data->platform_support);
-		if (!error)
+		if (error) {
+			thaw_processes();
+		} else {
 			error = put_user(in_suspend, (int __user *)arg);
-		if (!error)
-			data->ready = 1;
+			if (!error && !freezer_test_done)
+				data->ready = 1;
+			if (freezer_test_done) {
+				freezer_test_done = false;
+				thaw_processes();
+			}
+		}
 		break;
 
 	case SNAPSHOT_ATOMIC_RESTORE:

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