@@ -368,6 +368,7 @@ 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);
@@ -477,7 +478,20 @@ 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) {
+ memalloc_noio_save(noio_flag);
+ retval = rpm_callback(callback, dev);
+ memalloc_noio_restore(noio_flag);
+ } else {
+ retval = rpm_callback(callback, dev);
+ }
if (retval)
goto fail;
@@ -560,6 +574,7 @@ 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);
@@ -709,7 +724,20 @@ 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) {
+ 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);
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 <stern@rowland.harvard.edu> Cc: Oliver Neukum <oneukum@suse.de> Cc: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Ming Lei <ming.lei@canonical.com> --- 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(-)