Merge tag 'mmc-v4.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc

[mirror_ubuntu-bionic-kernel.git] / drivers / s390 / net / qeth_core_main.c

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 49b9efeba1bda1e2390289b8ba536fa7bad0542c..430e3214f7e26791af247d402734efb0ebb9cfc3 100644 (file)
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *    Copyright IBM Corp. 2007, 2009
  *    Author(s): Utz Bacher <utz.bacher@de.ibm.com>,
@@ -19,6 +20,11 @@
 #include <linux/mii.h>
 #include <linux/kthread.h>
 #include <linux/slab.h>
+#include <linux/if_vlan.h>
+#include <linux/netdevice.h>
+#include <linux/netdev_features.h>
+#include <linux/skbuff.h>
+
 #include <net/iucv/af_iucv.h>
 #include <net/dsfield.h>
 
@@ -6438,6 +6444,32 @@ netdev_features_t qeth_fix_features(struct net_device *dev,
 }
 EXPORT_SYMBOL_GPL(qeth_fix_features);
 
+netdev_features_t qeth_features_check(struct sk_buff *skb,
+                                     struct net_device *dev,
+                                     netdev_features_t features)
+{
+       /* GSO segmentation builds skbs with
+        *      a (small) linear part for the headers, and
+        *      page frags for the data.
+        * Compared to a linear skb, the header-only part consumes an
+        * additional buffer element. This reduces buffer utilization, and
+        * hurts throughput. So compress small segments into one element.
+        */
+       if (netif_needs_gso(skb, features)) {
+               /* match skb_segment(): */
+               unsigned int doffset = skb->data - skb_mac_header(skb);
+               unsigned int hsize = skb_shinfo(skb)->gso_size;
+               unsigned int hroom = skb_headroom(skb);
+
+               /* linearize only if resulting skb allocations are order-0: */
+               if (SKB_DATA_ALIGN(hroom + doffset + hsize) <= SKB_MAX_HEAD(0))
+                       features &= ~NETIF_F_SG;
+       }
+
+       return vlan_features_check(skb, features);
+}
+EXPORT_SYMBOL_GPL(qeth_features_check);
+
 static int __init qeth_core_init(void)
 {
        int rc;