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>
--
v7:
- move memalloc_noio_save/memalloc_noio_restore into
rpm_callback to avoid code duplication, as suggested
by Rafael
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 | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index cd92e1c..1244930 100644
--- 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;
--
1.7.9.5
--
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