[PATCH v9 bpf-next 02/14] xdp: introduce flags field in xdp_buff/xdp_frame

Lorenzo Bianconi
2021-06-14T12:50:43Z

Introduce flags field in xdp_frame/xdp_buffer data structure
to define additional buffer features. At the moment the only
supported buffer feature is multi-buffer bit (mb). Multi-buffer bit
is used to specify if this is a linear buffer (mb = 0) or a multi-buffer
frame (mb = 1). In the latter case the shared_info area at the end of
the first buffer will be properly initialized to link together
subsequent buffers.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
include/net/xdp.h | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/include/net/xdp.h b/include/net/xdp.h
index 5533f0ab2afc..de11d981fa44 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -66,6 +66,10 @@ struct xdp_txq_info {
struct net_device *dev;
};

+enum xdp_buff_flags {
+ XDP_FLAGS_MULTI_BUFF = BIT(0), /* non-linear xdp buff */
+};
+
struct xdp_buff {
void *data;
void *data_end;
@@ -74,13 +78,30 @@ struct xdp_buff {
struct xdp_rxq_info *rxq;
struct xdp_txq_info *txq;
u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/
+ u16 flags; /* supported values defined in xdp_flags */
};

+static __always_inline bool xdp_buff_is_mb(struct xdp_buff *xdp)
+{
+ return !!(xdp->flags & XDP_FLAGS_MULTI_BUFF);
+}
+
+static __always_inline void xdp_buff_set_mb(struct xdp_buff *xdp)
+{
+ xdp->flags |= XDP_FLAGS_MULTI_BUFF;
+}
+
+static __always_inline void xdp_buff_clear_mb(struct xdp_buff *xdp)
+{
+ xdp->flags &= ~XDP_FLAGS_MULTI_BUFF;
+}
+
static __always_inline void
xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq)
{
xdp->frame_sz = frame_sz;
xdp->rxq = rxq;
+ xdp->flags = 0;
}

static __always_inline void
@@ -117,13 +138,19 @@ struct xdp_frame {
u16 headroom;
u32 metasize:8;
u32 frame_sz:24;
+ struct net_device *dev_rx; /* used by cpumap */
/* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
* while mem info is valid on remote CPU.
*/
struct xdp_mem_info mem;
- struct net_device *dev_rx; /* used by cpumap */
+ u16 flags; /* supported values defined in xdp_flags */
};

+static __always_inline bool xdp_frame_is_mb(struct xdp_frame *frame)
+{
+ return !!(frame->flags & XDP_FLAGS_MULTI_BUFF);
+}
+
#define XDP_BULK_QUEUE_SIZE 16
struct xdp_frame_bulk {
int count;
@@ -180,6 +207,7 @@ 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->flags = frame->flags;
}

static inline
@@ -206,6 +234,7 @@ 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->flags = xdp->flags;

return 0;
}
--
2.31.1