[PATCH 4.9 46/59] s390/qeth: use vzalloc for QUERY OAT buffer

Greg Kroah-Hartman
2018-10-08T18:40:58Z

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

[ Upstream commit aec45e857c5538664edb76a60dd452e3265f37d1 ]

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@linux.ibm.com>
Reviewed-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/s390/net/qeth_core_main.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -23,6 +23,7 @@
#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>
@@ -4715,7 +4716,7 @@ int qeth_query_oat_command(struct qeth_c

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;
@@ -4756,7 +4757,7 @@ int qeth_query_oat_command(struct qeth_c
rc = -EFAULT;

out_free:
- kfree(priv.buffer);
+ vfree(priv.buffer);
out:
return rc;
}