This patch applies the introduced memalloc_noio_save() and
memalloc_noio_restore() to force memory allocation with no I/O
during runtime_resume callback on device which is marked as
memalloc_noio_resume.
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>
---
drivers/base/power/runtime.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 9fa6ea7..c9e26b9 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -575,6 +575,7 @@ 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);
@@ -724,7 +725,20 @@ 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_resume.
+ */
+ if (dev->power.memalloc_noio_resume) {
+ memalloc_noio_save(noio_flag);
+ 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
--
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