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Subject[PATCH V5 2/6 net-next] netdevice.h: Add zero-copy flag in netdevice
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Signed-off-by: Shirley Ma <xma@us.ibm.com>
---
include/linux/netdevice.h | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a134d80..2646251 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1066,6 +1066,16 @@ struct net_device {
#define NETIF_F_NOCACHE_COPY (1 << 30) /* Use no-cache copyfromuser */
#define NETIF_F_LOOPBACK (1 << 31) /* Enable loopback */

+/*
+ * Bit 31 is for device to map userspace buffers -- zerocopy
+ * Device can set this flag when it supports HIGHDMA.
+ * Device can't recycle this kind of skb buffers.
+ * There are 256 bytes copied, the rest of buffers are mapped.
+ * The userspace callback should only be called when last reference to this skb
+ * is gone.
+ */
+#define NETIF_F_ZEROCOPY (1 << 31)
+
/* Segmentation offload features */
#define NETIF_F_GSO_SHIFT 16
#define NETIF_F_GSO_MASK 0x00ff0000



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