[PATCH 5.9 220/757] samples/bpf: Fix to xdpsock to avoid recycling frames

Greg Kroah-Hartman
2020-10-27T15:58:25Z

From: Weqaar Janjua <weqaar.a.janjua@intel.com>

[ Upstream commit b69e56cf765155dcac0037d7d0f162a2afab76c2 ]

The txpush program in the xdpsock sample application is supposed
to send out all packets in the umem in a round-robin fashion.
The problem is that it only cycled through the first BATCH_SIZE
worth of packets. Fixed this so that it cycles through all buffers
in the umem as intended.

Fixes: 248c7f9c0e21 ("samples/bpf: convert xdpsock to use libbpf for AF_XDP access")
Signed-off-by: Weqaar Janjua <weqaar.a.janjua@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/20200828161717.42705-1-weqaar.a.janjua@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
samples/bpf/xdpsock_user.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
index 19c679456a0e2..c821e98671393 100644
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -1004,7 +1004,7 @@ static void rx_drop_all(void)
}
}

-static void tx_only(struct xsk_socket_info *xsk, u32 frame_nb, int batch_size)
+static void tx_only(struct xsk_socket_info *xsk, u32 *frame_nb, int batch_size)
{
u32 idx;
unsigned int i;
@@ -1017,14 +1017,14 @@ static void tx_only(struct xsk_socket_info *xsk, u32 frame_nb, int batch_size)
for (i = 0; i < batch_size; i++) {
struct xdp_desc *tx_desc = xsk_ring_prod__tx_desc(&xsk->tx,
idx + i);
- tx_desc->addr = (frame_nb + i) << XSK_UMEM__DEFAULT_FRAME_SHIFT;
+ tx_desc->addr = (*frame_nb + i) << XSK_UMEM__DEFAULT_FRAME_SHIFT;
tx_desc->len = PKT_SIZE;
}

xsk_ring_prod__submit(&xsk->tx, batch_size);
xsk->outstanding_tx += batch_size;
- frame_nb += batch_size;
- frame_nb %= NUM_FRAMES;
+ *frame_nb += batch_size;
+ *frame_nb %= NUM_FRAMES;
complete_tx_only(xsk, batch_size);
}

@@ -1080,7 +1080,7 @@ static void tx_only_all(void)
}

for (i = 0; i < num_socks; i++)
- tx_only(xsks[i], frame_nb[i], batch_size);
+ tx_only(xsks[i], &frame_nb[i], batch_size);

pkt_cnt += batch_size;

--
2.25.1