[SRU][Bionic][Cosmic][PATCH 1/1] s390/qeth: use vzalloc for QUERY OAT buffer

[Joseph Salisbury]

From: Wenjia Zhang <wenjia at linux.ibm.com>

BugLink: https://bugs.launchpad.net/bugs/1793086

qeth_query_oat_command() currently allocates the kernel buffer for
the SIOC_QETH_QUERY_OAT ioctl with kzalloc. So on systems with
fragmented memory, large allocations may fail (eg. the qethqoat tool by
default uses 132KB).

Solve this issue by using vzalloc, backing the allocation with
non-contiguous memory.

Signed-off-by: Wenjia Zhang <wenjia at linux.ibm.com>
Reviewed-by: Julian Wiedmann <jwi at linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi at linux.ibm.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit aec45e857c5538664edb76a60dd452e3265f37d1)
Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
---
 drivers/s390/net/qeth_core_main.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index d01ac29..02b7352 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -25,6 +25,7 @@
 #include <linux/netdevice.h>
 #include <linux/netdev_features.h>
 #include <linux/skbuff.h>
+#include <linux/vmalloc.h>
 
 #include <net/iucv/af_iucv.h>
 #include <net/dsfield.h>
@@ -4737,7 +4738,7 @@ static int qeth_query_oat_command(struct qeth_card *card, char __user *udata)
 
 	priv.buffer_len = oat_data.buffer_len;
 	priv.response_len = 0;
-	priv.buffer =  kzalloc(oat_data.buffer_len, GFP_KERNEL);
+	priv.buffer = vzalloc(oat_data.buffer_len);
 	if (!priv.buffer) {
 		rc = -ENOMEM;
 		goto out;
@@ -4778,7 +4779,7 @@ static int qeth_query_oat_command(struct qeth_card *card, char __user *udata)
 			rc = -EFAULT;
 
 out_free:
-	kfree(priv.buffer);
+	vfree(priv.buffer);
 out:
 	return rc;
 }
-- 
2.7.4