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authorXie Xiaobo <xiaobo.xie@nxp.com>2017-12-12 08:12:33 (GMT)
committerXie Xiaobo <xiaobo.xie@nxp.com>2017-12-12 08:12:33 (GMT)
commitc0246a9ec4d461ef4dd7647f94005380bb9e7f0b (patch)
tree7588601aa6ce98f5e9fd083a1b351d9023c0b295 /drivers/net/virtio_net.c
parent50fd1a6d79d48a7c35890aecce5a5d6b872a461d (diff)
parent56f4a560c6d6318b5a8e18a1b3e44909a5158d1e (diff)
downloadlinux-c0246a9ec4d461ef4dd7647f94005380bb9e7f0b.tar.xz
Merge Linaro linux 4.9.62 into linux-4.9
Signed-off-by: Xiaobo Xie <xiaobo.xie@nxp.com>
Diffstat (limited to 'drivers/net/virtio_net.c')
-rw-r--r--drivers/net/virtio_net.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f4ec348..15e87ad 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -47,8 +47,16 @@ module_param(gso, bool, 0444);
*/
DECLARE_EWMA(pkt_len, 1, 64)
+/* With mergeable buffers we align buffer address and use the low bits to
+ * encode its true size. Buffer size is up to 1 page so we need to align to
+ * square root of page size to ensure we reserve enough bits to encode the true
+ * size.
+ */
+#define MERGEABLE_BUFFER_MIN_ALIGN_SHIFT ((PAGE_SHIFT + 1) / 2)
+
/* Minimum alignment for mergeable packet buffers. */
-#define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, 256)
+#define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, \
+ 1 << MERGEABLE_BUFFER_MIN_ALIGN_SHIFT)
#define VIRTNET_DRIVER_VERSION "1.0.0"