Re: [PATCH V5 2/6 net-next] netdevice.h: Add zero-copy flag in netdevice
From: Ben Hutchings <hidden>
Date: 2011-05-16 19:35:26
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On Mon, 2011-05-16 at 12:28 -0700, Shirley Ma wrote:
quoted hunk ↗ jump to hunk
Signed-off-by: Shirley Ma <redacted> --- 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)
Sorry, bit 31 is taken. You get the job of turning features into a wider bitmap. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.