[dm-devel] [PATCH 1/7] dm: use __GFP_HIGH instead PF_MEMALLOC

[KOSAKI Motohiro]

Non MM subsystem must not use PF_MEMALLOC. Memory reclaim need few
memory, anyone must not prevent it. Otherwise the system cause
mysterious hang-up and/or OOM Killer invokation.

Cc: Alasdair G Kergon <agk at redhat.com>
Cc: dm-devel at redhat.com
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro at jp.fujitsu.com>
---
 drivers/md/dm-ioctl.c |   18 +++++++-----------
 1 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index a679429..4d24b0a 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1396,7 +1396,13 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
 	if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data)))
 		return -EINVAL;
 
-	dmi = vmalloc(tmp.data_size);
+
+	/*
+	 * We use __vmalloc(__GFP_HIGH) instead vmalloc() because trying to
+	 * avoid low memory issues when a device is suspended.
+	 */
+	dmi = __vmalloc(tmp.data_size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_HIGH,
+			PAGE_KERNEL);
 	if (!dmi)
 		return -ENOMEM;
 
@@ -1473,20 +1479,10 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
 		DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
 		return -ENOTTY;
 	}
-
-	/*
-	 * Trying to avoid low memory issues when a device is
-	 * suspended.
-	 */
-	current->flags |= PF_MEMALLOC;
-
 	/*
 	 * Copy the parameters into kernel space.
 	 */
 	r = copy_params(user, &param);
-
-	current->flags &= ~PF_MEMALLOC;
-
 	if (r)
 		return r;
 
-- 
1.6.2.5