net: ena: Use bitmask to indicate packet redirection

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: a318c70ad152 ("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>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.h b/drivers/net/ethernet/amazon/ena/ena_netdev.h
index 1bdce99bf688..290ae9bf47ee 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.h
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.h
@@ -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;