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authorSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>2012-02-04 01:22:41 +0400
committerRafael J. Wysocki <rjw@sisk.pl>2012-02-05 01:23:05 +0400
commit379e0be812ab8a2a351e784b0c987788f5123090 (patch)
tree70f1e7ac57e198d0a94a89a65933da9a2ca35ccc /kernel/power/power.h
parentfe9161db2e6053da21e4649d77bbefaf3030b11d (diff)
downloadlinux-379e0be812ab8a2a351e784b0c987788f5123090.tar.xz
PM / Freezer: Thaw only kernel threads if freezing of kernel threads fails
If freezing of kernel threads fails, we are expected to automatically thaw tasks in the error recovery path. However, at times, we encounter situations in which we would like the automatic error recovery path to thaw only the kernel threads, because we want to be able to do some more cleanup before we thaw userspace. Something like: error = freeze_kernel_threads(); if (error) { /* Do some cleanup */ /* Only then thaw userspace tasks*/ thaw_processes(); } An example of such a situation is where we freeze/thaw filesystems during suspend/hibernation. There, if freezing of kernel threads fails, we would like to thaw the frozen filesystems before thawing the userspace tasks. So, modify freeze_kernel_threads() to thaw only kernel threads in case of freezing failure. And change suspend_freeze_processes() accordingly. (At the same time, let us also get rid of the rather cryptic usage of the conditional operator (:?) in that function.) [rjw: In fact, this patch fixes a regression introduced during the 3.3 merge window, because without it thaw_processes() may be called before swsusp_free() in some situations and that may lead to massive memory allocation failures.] Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Nigel Cunningham <nigel@tuxonice.net> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'kernel/power/power.h')
-rw-r--r--kernel/power/power.h24
1 files changed, 22 insertions, 2 deletions
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 0c4defe6d3b8..21724eee5206 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -231,8 +231,28 @@ extern int pm_test_level;
#ifdef CONFIG_SUSPEND_FREEZER
static inline int suspend_freeze_processes(void)
{
- int error = freeze_processes();
- return error ? : freeze_kernel_threads();
+ int error;
+
+ error = freeze_processes();
+
+ /*
+ * freeze_processes() automatically thaws every task if freezing
+ * fails. So we need not do anything extra upon error.
+ */
+ if (error)
+ goto Finish;
+
+ error = freeze_kernel_threads();
+
+ /*
+ * freeze_kernel_threads() thaws only kernel threads upon freezing
+ * failure. So we have to thaw the userspace tasks ourselves.
+ */
+ if (error)
+ thaw_processes();
+
+ Finish:
+ return error;
}
static inline void suspend_thaw_processes(void)