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>
diff --git a/kernel/power/process.c b/kernel/power/process.c
index e59676f..ce64383 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -91,11 +91,6 @@
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 @@
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 @@
/**
* 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 @@
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 @@
printk("\n");
BUG_ON(in_atomic());
+ if (error)
+ thaw_processes();
return error;
}