[v6,3/6] block/genhd.c: apply pm_runtime_set_memalloc_noio on block devices

Commit Message

Ming Lei Nov. 24, 2012, 12:59 p.m. UTC

This patch applyes the introduced pm_runtime_set_memalloc_noio on
block device so that PM core will teach mm to not allocate memory with
GFP_IOFS when calling the runtime_resume and runtime_suspend callback
for block devices and its ancestors.

Cc: Jens Axboe <[e-mail]>
Signed-off-by: Ming Lei <[e-mail]>
---
v5:
	- fix code style and one typo
v4:
	- call pm_runtime_set_memalloc_noio(ddev, true) after device_add
---
 block/genhd.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

Patch

diff --git a/block/genhd.c b/block/genhd.c
index 9a289d7..1905966 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -18,6 +18,7 @@ 
 #include <linux/mutex.h>
 #include <linux/idr.h>
 #include <linux/log2.h>
+#include <linux/pm_runtime.h>
 
 #include "blk.h"
 
@@ -532,6 +533,14 @@  static void register_disk(struct gendisk *disk)
 			return;
 		}
 	}
+
+	/*
+	 * avoid probable deadlock caused by allocating memory with
+	 * GFP_KERNEL in runtime_resume callback of its all ancestor
+	 * devices
+	 */
+	pm_runtime_set_memalloc_noio(ddev, true);
+
 	disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
 	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
 
@@ -661,6 +670,7 @@  void del_gendisk(struct gendisk *disk)
 	disk->driverfs_dev = NULL;
 	if (!sysfs_deprecated)
 		sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
+	pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
 	device_del(disk_to_dev(disk));
 }
 EXPORT_SYMBOL(del_gendisk);