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authorTejun Heo <tj@kernel.org>2011-11-21 12:32:24 -0800
committerTejun Heo <tj@kernel.org>2011-11-21 12:32:24 -0800
commit03afed8bc296fa70186ba832c1126228bb992465 (patch)
tree96d0a6a9bffdcfc678d31f21caa88e43693bde94 /kernel/power
parent376fede80e74d98b49d1ba9ac18f23c9fd026ddd (diff)
freezer: clean up freeze_processes() failure path
freeze_processes() failure path is rather messy. Freezing is canceled for workqueues and tasks which aren't frozen yet but frozen tasks are left alone and should be thawed by the caller and of course some callers (xen and kexec) didn't do it. This patch updates __thaw_task() to handle cancelation correctly and makes freeze_processes() and freeze_kernel_threads() call thaw_processes() on failure instead so that the system is fully thawed on failure. Unnecessary [suspend_]thaw_processes() calls are removed from kernel/power/hibernate.c, suspend.c and user.c. While at it, restructure error checking if clause in suspend_prepare() to be less weird. -v2: Srivatsa spotted missing removal of suspend_thaw_processes() in suspend_prepare() and error in commit message. Updated. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/power')
-rw-r--r--kernel/power/hibernate.c15
-rw-r--r--kernel/power/process.c16
-rw-r--r--kernel/power/suspend.c8
-rw-r--r--kernel/power/user.c4
4 files changed, 14 insertions, 29 deletions
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 196c01268eb..ba2319ffc86 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -607,17 +607,6 @@ static void power_down(void)
while(1);
}
-static int prepare_processes(void)
-{
- int error = 0;
-
- if (freeze_processes()) {
- error = -EBUSY;
- thaw_processes();
- }
- return error;
-}
-
/**
* hibernate - Carry out system hibernation, including saving the image.
*/
@@ -650,7 +639,7 @@ int hibernate(void)
sys_sync();
printk("done.\n");
- error = prepare_processes();
+ error = freeze_processes();
if (error)
goto Finish;
@@ -811,7 +800,7 @@ static int software_resume(void)
goto close_finish;
pr_debug("PM: Preparing processes for restore.\n");
- error = prepare_processes();
+ error = freeze_processes();
if (error) {
swsusp_close(FMODE_READ);
goto Done;
diff --git a/kernel/power/process.c b/kernel/power/process.c
index e59676f5811..ce643838a00 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -91,11 +91,6 @@ static int try_to_freeze_tasks(bool sig_only)
elapsed_csecs = elapsed_csecs64;
if (todo) {
- /* This does not unfreeze processes that are already frozen
- * (we have slightly ugly calling convention in that respect,
- * and caller must call thaw_processes() if something fails),
- * but it cleans up leftover PF_FREEZE requests.
- */
printk("\n");
printk(KERN_ERR "Freezing of tasks %s after %d.%02d seconds "
"(%d tasks refusing to freeze, wq_busy=%d):\n",
@@ -103,14 +98,11 @@ static int try_to_freeze_tasks(bool sig_only)
elapsed_csecs / 100, elapsed_csecs % 100,
todo - wq_busy, wq_busy);
- thaw_workqueues();
-
read_lock(&tasklist_lock);
do_each_thread(g, p) {
if (!wakeup && !freezer_should_skip(p) &&
freezing(p) && !frozen(p))
sched_show_task(p);
- cancel_freezing(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
} else {
@@ -123,6 +115,8 @@ static int try_to_freeze_tasks(bool sig_only)
/**
* freeze_processes - Signal user space processes to enter the refrigerator.
+ *
+ * On success, returns 0. On failure, -errno and system is fully thawed.
*/
int freeze_processes(void)
{
@@ -137,11 +131,15 @@ int freeze_processes(void)
printk("\n");
BUG_ON(in_atomic());
+ if (error)
+ thaw_processes();
return error;
}
/**
* freeze_kernel_threads - Make freezable kernel threads go to the refrigerator.
+ *
+ * On success, returns 0. On failure, -errno and system is fully thawed.
*/
int freeze_kernel_threads(void)
{
@@ -155,6 +153,8 @@ int freeze_kernel_threads(void)
printk("\n");
BUG_ON(in_atomic());
+ if (error)
+ thaw_processes();
return error;
}
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 4953dc054c5..d336b27d110 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -106,13 +106,11 @@ static int suspend_prepare(void)
goto Finish;
error = suspend_freeze_processes();
- if (error) {
- suspend_stats.failed_freeze++;
- dpm_save_failed_step(SUSPEND_FREEZE);
- } else
+ if (!error)
return 0;
- suspend_thaw_processes();
+ suspend_stats.failed_freeze++;
+ dpm_save_failed_step(SUSPEND_FREEZE);
usermodehelper_enable();
Finish:
pm_notifier_call_chain(PM_POST_SUSPEND);
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 6d8f535c2b8..7cc3f5bc5c2 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -257,10 +257,8 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
break;
error = freeze_processes();
- if (error) {
- thaw_processes();
+ if (error)
usermodehelper_enable();
- }
if (!error)
data->frozen = 1;
break;