RE: [RFC net-next 01/22] xdp: introduce mb in xdp_buff/xdp_frame

-----Original Message-----
From: Lorenzo Bianconi <lorenzo@kernel.org>
Sent: Thursday, July 23, 2020 2:42 PM
To: netdev@vger.kernel.org
Cc: bpf@vger.kernel.org; davem@davemloft.net; ast@kernel.org;
brouer@redhat.com; daniel@iogearbox.net; lorenzo.bianconi@redhat.com;
echaudro@redhat.com; Jubran, Samih [off-list ref];
kuba@kernel.org
Subject: [EXTERNAL] [RFC net-next 01/22] xdp: introduce mb in
xdp_buff/xdp_frame

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Introduce multi-buffer bit (mb) in xdp_frame/xdp_buffer to specify if
shared_info area has been properly initialized for non-linear xdp buffers

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 include/net/xdp.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/net/xdp.h b/include/net/xdp.h index

dbe9c60797e1..2ef6935c5646 100644

--- a/include/net/xdp.h
+++ b/include/net/xdp.h

@@ -72,7 +72,8 @@ struct xdp_buff {
        void *data_hard_start;
        struct xdp_rxq_info *rxq;
        struct xdp_txq_info *txq;
-       u32 frame_sz; /* frame size to deduce data_hard_end/reserved

tailroom*/
+       u32 frame_sz:31; /* frame size to deduce data_hard_end/reserved
tailroom*/

+       u32 mb:1; /* xdp non-linear buffer */
 };

 /* Reserve memory area at end-of data area.

@@ -96,7 +97,8 @@ struct xdp_frame {
        u16 len;
        u16 headroom;
        u32 metasize:8;
-       u32 frame_sz:24;
+       u32 frame_sz:23;
+       u32 mb:1; /* xdp non-linear frame */
        /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
         * while mem info is valid on remote CPU.
         */

@@ -141,6 +143,7 @@ void xdp_convert_frame_to_buff(struct xdp_frame

*frame, struct xdp_buff *xdp)
        xdp->data_end = frame->data + frame->len;
        xdp->data_meta = frame->data - frame->metasize;
        xdp->frame_sz = frame->frame_sz;
+       xdp->mb = frame->mb;
 }

 static inline

@@ -167,6 +170,7 @@ int xdp_update_frame_from_buff(struct xdp_buff

*xdp,
        xdp_frame->headroom = headroom - sizeof(*xdp_frame);
        xdp_frame->metasize = metasize;
        xdp_frame->frame_sz = xdp->frame_sz;
+       xdp_frame->mb = xdp->mb;

        return 0;
 }
--
2.26.2