s390/qeth: use vzalloc for QUERY OAT buffer

[ Upstream commit aec45e8 ]

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>

Author: Wenjia Zhang

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>
@@ -4728,7 +4729,7 @@ 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;
@@ -4769,7 +4770,7 @@ 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;
 }