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net: ena: Use bitmask to indicate packet redirection

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Redirecting packets with XDP Redirect is done in two phases:
1. A packet is passed by the driver to the kernel using
   xdp_do_redirect().
2. After finishing polling for new packets the driver lets the kernel
   know that it can now process the redirected packet using
   xdp_do_flush_map().
   The packets' redirection is handled in the napi context of the
   queue that called xdp_do_redirect()

To avoid calling xdp_do_flush_map() each time the driver first checks
whether any packets were redirected, using
	xdp_flags |= xdp_verdict;
and
	if (xdp_flags & XDP_REDIRECT)
	    xdp_do_flush_map()

essentially treating XDP instructions as a bitmask, which isn't the case:
    enum xdp_action {
	    XDP_ABORTED = 0,
	    XDP_DROP,
	    XDP_PASS,
	    XDP_TX,
	    XDP_REDIRECT,
    };

Given the current possible values of xdp_action, the current design
doesn't have a bug (since XDP_REDIRECT = 100b), but it is still
flawed.

This patch makes the driver use a bitmask instead, to avoid future
issues.

Fixes: a318c70ad1 ("net: ena: introduce XDP redirect implementation")
Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Arinzon 2022-12-29 07:30:08 +00:00 committed by David S. Miller
parent c7f5e34d90
commit 59811faa2c
2 changed files with 25 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
drivers/net/ethernet/amazon/ena/ena_netdev.c
View File

@ -374,9 +374,9 @@ static int ena_xdp_xmit(struct net_device *dev, int n,
static int ena_xdp_execute(struct ena_ring *rx_ring, struct xdp_buff *xdp)
{
u32 verdict = ENA_XDP_PASS;
struct bpf_prog *xdp_prog;
struct ena_ring *xdp_ring;
u32 verdict = XDP_PASS;
struct xdp_frame *xdpf;
u64 *xdp_stat;
@ -393,7 +393,7 @@ static int ena_xdp_execute(struct ena_ring *rx_ring, struct xdp_buff *xdp)
if (unlikely(!xdpf)) {
trace_xdp_exception(rx_ring->netdev, xdp_prog, verdict);
xdp_stat = &rx_ring->rx_stats.xdp_aborted;
verdict = XDP_ABORTED;
verdict = ENA_XDP_DROP;
break;
}
@ -409,29 +409,35 @@ static int ena_xdp_execute(struct ena_ring *rx_ring, struct xdp_buff *xdp)
spin_unlock(&xdp_ring->xdp_tx_lock);
xdp_stat = &rx_ring->rx_stats.xdp_tx;
verdict = ENA_XDP_TX;
break;
case XDP_REDIRECT:
if (likely(!xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog))) {
xdp_stat = &rx_ring->rx_stats.xdp_redirect;
verdict = ENA_XDP_REDIRECT;
break;
}
trace_xdp_exception(rx_ring->netdev, xdp_prog, verdict);
xdp_stat = &rx_ring->rx_stats.xdp_aborted;
verdict = XDP_ABORTED;
verdict = ENA_XDP_DROP;
break;
case XDP_ABORTED:
trace_xdp_exception(rx_ring->netdev, xdp_prog, verdict);
xdp_stat = &rx_ring->rx_stats.xdp_aborted;
verdict = ENA_XDP_DROP;
break;
case XDP_DROP:
xdp_stat = &rx_ring->rx_stats.xdp_drop;
verdict = ENA_XDP_DROP;
break;
case XDP_PASS:
xdp_stat = &rx_ring->rx_stats.xdp_pass;
verdict = ENA_XDP_PASS;
break;
default:
bpf_warn_invalid_xdp_action(rx_ring->netdev, xdp_prog, verdict);
xdp_stat = &rx_ring->rx_stats.xdp_invalid;
verdict = ENA_XDP_DROP;
}
ena_increase_stat(xdp_stat, 1, &rx_ring->syncp);
@ -1621,12 +1627,12 @@ static int ena_xdp_handle_buff(struct ena_ring *rx_ring, struct xdp_buff *xdp)
* we expect, then we simply drop it
*/
if (unlikely(rx_ring->ena_bufs[0].len > ENA_XDP_MAX_MTU))
return XDP_DROP;
return ENA_XDP_DROP;
ret = ena_xdp_execute(rx_ring, xdp);
/* The xdp program might expand the headers */
if (ret == XDP_PASS) {
if (ret == ENA_XDP_PASS) {
rx_info->page_offset = xdp->data - xdp->data_hard_start;
rx_ring->ena_bufs[0].len = xdp->data_end - xdp->data;
}
@ -1665,7 +1671,7 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
xdp_init_buff(&xdp, ENA_PAGE_SIZE, &rx_ring->xdp_rxq);
do {
xdp_verdict = XDP_PASS;
xdp_verdict = ENA_XDP_PASS;
skb = NULL;
ena_rx_ctx.ena_bufs = rx_ring->ena_bufs;
ena_rx_ctx.max_bufs = rx_ring->sgl_size;
@ -1693,7 +1699,7 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
xdp_verdict = ena_xdp_handle_buff(rx_ring, &xdp);
/* allocate skb and fill it */
if (xdp_verdict == XDP_PASS)
if (xdp_verdict == ENA_XDP_PASS)
skb = ena_rx_skb(rx_ring,
rx_ring->ena_bufs,
ena_rx_ctx.descs,
@ -1711,13 +1717,13 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
/* Packets was passed for transmission, unmap it
* from RX side.
*/
if (xdp_verdict == XDP_TX || xdp_verdict == XDP_REDIRECT) {
if (xdp_verdict & ENA_XDP_FORWARDED) {
ena_unmap_rx_buff(rx_ring,
&rx_ring->rx_buffer_info[req_id]);
rx_ring->rx_buffer_info[req_id].page = NULL;
}
}
if (xdp_verdict != XDP_PASS) {
if (xdp_verdict != ENA_XDP_PASS) {
xdp_flags |= xdp_verdict;
total_len += ena_rx_ctx.ena_bufs[0].len;
res_budget--;
@ -1763,7 +1769,7 @@ static int ena_clean_rx_irq(struct ena_ring *rx_ring, struct napi_struct *napi,
ena_refill_rx_bufs(rx_ring, refill_required);
}
if (xdp_flags & XDP_REDIRECT)
if (xdp_flags & ENA_XDP_REDIRECT)
xdp_do_flush_map();
return work_done;

9
drivers/net/ethernet/amazon/ena/ena_netdev.h
View File

@ -409,6 +409,15 @@ enum ena_xdp_errors_t {
ENA_XDP_NO_ENOUGH_QUEUES,
};
enum ENA_XDP_ACTIONS {
ENA_XDP_PASS = 0,
ENA_XDP_TX = BIT(0),
ENA_XDP_REDIRECT = BIT(1),
ENA_XDP_DROP = BIT(2)
};
#define ENA_XDP_FORWARDED (ENA_XDP_TX | ENA_XDP_REDIRECT)
static inline bool ena_xdp_present(struct ena_adapter *adapter)
{
return !!adapter->xdp_bpf_prog;