On Saturday, November 24, 2012 08:59:17 PM Ming Lei wrote: > 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@xxxxxxxxxxxxxxxxxxx> > Cc: Oliver Neukum <oneukum@xxxxxxx> > Cc: Rafael J. Wysocki <rjw@xxxxxxx> > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx> > --- > 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); > + } Please don't duplicate code this way. You can move that whole thing to rpm_callback(). Yes, you'll probably need to check dev->power.memalloc_noio twice in there, but that's OK. > if (retval) { > __update_runtime_status(dev, RPM_SUSPENDED); > pm_runtime_cancel_pending(dev); > Thanks, Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html