pm / runtime: force memory allocation with no I/O during Runtime PM callbcack

[karo-tx-linux.git] / drivers / base / power / runtime.c

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index cd92e1c77cb72933d54c07bac49a86b240dfaab1..1244930e3d7a4ae73843afb7ecb34c356a5cc72b 100644 (file)
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -348,7 +348,24 @@ static int rpm_callback(int (*cb)(struct device *), struct device *dev)
        if (!cb)
                return -ENOSYS;
 
-       retval = __rpm_callback(cb, dev);
+       if (dev->power.memalloc_noio) {
+               unsigned int noio_flag;
+
+               /*
+                * Deadlock might be caused if memory allocation with
+                * GFP_KERNEL happens inside runtime_suspend and
+                * runtime_resume callbacks 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 too.
+                */
+               noio_flag = memalloc_noio_save();
+               retval = __rpm_callback(cb, dev);
+               memalloc_noio_restore(noio_flag);
+       } else {
+               retval = __rpm_callback(cb, dev);
+       }
 
        dev->power.runtime_error = retval;
        return retval != -EACCES ? retval : -EIO;