This patch applies the introduced memalloc_noio_save() and
memalloc_noio_restore() to force memory allocation with no I/O
during runtime_resume/runtime_suspend callback on device with
the flag of 'memalloc_noio' set.
Cc: Alan Stern <st...@rowland.harvard.edu>
Cc: Oliver Neukum <oneu...@suse.de>
Cc: Rafael J. Wysocki <r...@sisk.pl>
Signed-off-by: Ming Lei <ming....@canonical.com>
---
v5:
- use inline memalloc_noio_save()
v4:
- runtime_suspend need this too because rpm_resume may wait for
completion of concurrent runtime_suspend, so deadlock still may
be triggered in runtime_suspend path.
---
drivers/base/power/runtime.c | 32 ++++++++++++++++++++++++++++++--
1 file changed, 30 insertions(+), 2 deletions(-)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 3e198a0..96d99ea 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -371,6 +371,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
int (*callback)(struct device *);
struct device *parent = NULL;
int retval;
+ unsigned int noio_flag;
trace_rpm_suspend(dev, rpmflags);
@@ -480,7 +481,20 @@ static int rpm_suspend(struct device *dev, int rpmflags)
if (!callback && dev->driver && dev->driver->pm)
callback = dev->driver->pm->runtime_suspend;
- retval = rpm_callback(callback, dev);
+ /*
+ * Deadlock might be caused if memory allocation with GFP_KERNEL
+ * happens inside runtime_suspend callback of one block device's
+ * ancestor or the block device itself. Network device might be
+ * thought as part of iSCSI block device, so network device and
+ * its ancestor should be marked as memalloc_noio.
+ */
+ if (dev->power.memalloc_noio) {
+ noio_flag = memalloc_noio_save();
+ retval = rpm_callback(callback, dev);
+ memalloc_noio_restore(noio_flag);
+ } else {
+ retval = rpm_callback(callback, dev);
+ }
if (retval)
goto fail;
@@ -563,6 +577,7 @@ static int rpm_resume(struct device *dev, int rpmflags)
int (*callback)(struct device *);
struct device *parent = NULL;
int retval = 0;
+ unsigned int noio_flag;
trace_rpm_resume(dev, rpmflags);
@@ -712,7 +727,20 @@ static int rpm_resume(struct device *dev, int rpmflags)
if (!callback && dev->driver && dev->driver->pm)
callback = dev->driver->pm->runtime_resume;
- retval = rpm_callback(callback, dev);
+ /*
+ * Deadlock might be caused if memory allocation with GFP_KERNEL
+ * happens inside runtime_resume callback of one block device's
+ * ancestor or the block device itself. Network device might be
+ * thought as part of iSCSI block device, so network device and
+ * its ancestor should be marked as memalloc_noio.
+ */
+ if (dev->power.memalloc_noio) {
+ noio_flag = memalloc_noio_save();
+ retval = rpm_callback(callback, dev);
+ memalloc_noio_restore(noio_flag);
+ } else {
+ retval = rpm_callback(callback, dev);
+ }
if (retval) {
__update_runtime_status(dev, RPM_SUSPENDED);
pm_runtime_cancel_pending(dev);
--
1.7.9.5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
