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xdp: fix bug in devmap teardown code path 

Like cpumap teardown, the devmap teardown code also flush remaining
xdp_frames, via bq_xmit_all() in case map entry is removed.  The code
can call xdp_return_frame_rx_napi, from the the wrong context, in-case
ndo_xdp_xmit() fails.

Fixes: 389ab7f01a ("xdp: introduce xdp_return_frame_rx_napi")
Fixes: 735fc4054b ("xdp: change ndo_xdp_xmit API to support bulking")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Jesper Dangaard Brouer 2018-08-08 23:00:45 +02:00 committed by Daniel Borkmann
parent 37d7ff2595
commit 1bf9116d08
1 changed files with 9 additions and 5 deletions
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14
kernel/bpf/devmap.c
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@ -217,7 +217,8 @@ void __dev_map_insert_ctx(struct bpf_map *map, u32 bit)
}
static int bq_xmit_all(struct bpf_dtab_netdev *obj,
struct xdp_bulk_queue *bq, u32 flags)
struct xdp_bulk_queue *bq, u32 flags,
bool in_napi_ctx)
{
struct net_device *dev = obj->dev;
int sent = 0, drops = 0, err = 0;
@ -254,7 +255,10 @@ static int bq_xmit_all(struct bpf_dtab_netdev *obj,
struct xdp_frame *xdpf = bq->q[i];
/* RX path under NAPI protection, can return frames faster */
xdp_return_frame_rx_napi(xdpf);
if (likely(in_napi_ctx))
xdp_return_frame_rx_napi(xdpf);
else
xdp_return_frame(xdpf);
drops++;
}
goto out;
@ -286,7 +290,7 @@ void __dev_map_flush(struct bpf_map *map)
__clear_bit(bit, bitmap);
bq = this_cpu_ptr(dev->bulkq);
bq_xmit_all(dev, bq, XDP_XMIT_FLUSH);
bq_xmit_all(dev, bq, XDP_XMIT_FLUSH, true);
}
}
@ -316,7 +320,7 @@ static int bq_enqueue(struct bpf_dtab_netdev *obj, struct xdp_frame *xdpf,
struct xdp_bulk_queue *bq = this_cpu_ptr(obj->bulkq);
if (unlikely(bq->count == DEV_MAP_BULK_SIZE))
bq_xmit_all(obj, bq, 0);
bq_xmit_all(obj, bq, 0, true);
/* Ingress dev_rx will be the same for all xdp_frame's in
* bulk_queue, because bq stored per-CPU and must be flushed
@ -385,7 +389,7 @@ static void dev_map_flush_old(struct bpf_dtab_netdev *dev)
__clear_bit(dev->bit, bitmap);
bq = per_cpu_ptr(dev->bulkq, cpu);
bq_xmit_all(dev, bq, XDP_XMIT_FLUSH);
bq_xmit_all(dev, bq, XDP_XMIT_FLUSH, false);
}
}
}