net/af_xdp: fix build with Linux < 5.4

Prior to this change, two implementations of rx_syscall_handler
existed although only one was needed (for the zero copy path which
is only available from kernel 5.4 and onwards). Remove the second
definition from compat.h and move the first definition back to where
it is called in the Rx function. Doing this removes a build warning
on kernels before 5.4 which complained about the second function
being defined but not used.

Fixes: 2aa51cdd559e ("net/af_xdp: fix trigger for syscall on Tx")
Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>

diff --git a/drivers/net/af_xdp/compat.h b/drivers/net/af_xdp/compat.h
index 52fd447b69b6d3000259007fe983b27a436830c8..3880dc7dd7f5b42b67ff6e0e6d31a4966f31a8bd 100644 (file)
--- a/drivers/net/af_xdp/compat.h
+++ b/drivers/net/af_xdp/compat.h
@@ -42,37 +42,12 @@ create_shared_socket(struct xsk_socket **xsk_ptr __rte_unused,
 #endif
 
 #ifdef XDP_USE_NEED_WAKEUP
-static void
-rx_syscall_handler(struct xsk_ring_prod *q, uint32_t busy_budget,
-                  struct pollfd *fds, struct xsk_socket *xsk)
-{
-       /* we can assume a kernel >= 5.11 is in use if busy polling is enabled
-        * and thus we can safely use the recvfrom() syscall which is only
-        * supported for AF_XDP sockets in kernels >= 5.11.
-        */
-       if (busy_budget) {
-               (void)recvfrom(xsk_socket__fd(xsk), NULL, 0,
-                       MSG_DONTWAIT, NULL, NULL);
-               return;
-       }
-
-       if (xsk_ring_prod__needs_wakeup(q))
-               (void)poll(fds, 1, 1000);
-}
 static int
 tx_syscall_needed(struct xsk_ring_prod *q)
 {
        return xsk_ring_prod__needs_wakeup(q);
 }
 #else
-static void
-rx_syscall_handler(struct xsk_ring_prod *q __rte_unused, uint32_t busy_budget,
-                  struct pollfd *fds __rte_unused, struct xsk_socket *xsk)
-{
-       if (busy_budget)
-               (void)recvfrom(xsk_socket__fd(xsk), NULL, 0,
-                       MSG_DONTWAIT, NULL, NULL);
-}
 static int
 tx_syscall_needed(struct xsk_ring_prod *q __rte_unused)
 {

diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c b/drivers/net/af_xdp/rte_eth_af_xdp.c
index c2db21f9c1d80374dbf191af447f6ee2d5f1296a..eb5660a3dcab7b69c67a5bcd634e35ba86c40e88 100644 (file)
--- a/drivers/net/af_xdp/rte_eth_af_xdp.c
+++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
@@ -272,8 +272,18 @@ af_xdp_rx_zc(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
        nb_pkts = xsk_ring_cons__peek(rx, nb_pkts, &idx_rx);
 
        if (nb_pkts == 0) {
-               rx_syscall_handler(&rxq->fq, rxq->busy_budget, &rxq->fds[0],
-                                  rxq->xsk);
+               /* we can assume a kernel >= 5.11 is in use if busy polling is
+                * enabled and thus we can safely use the recvfrom() syscall
+                * which is only supported for AF_XDP sockets in kernels >=
+                * 5.11.
+                */
+               if (rxq->busy_budget) {
+                       (void)recvfrom(xsk_socket__fd(rxq->xsk), NULL, 0,
+                                      MSG_DONTWAIT, NULL, NULL);
+               } else if (xsk_ring_prod__needs_wakeup(fq)) {
+                       (void)poll(&rxq->fds[0], 1, 1000);
+               }
+
                return 0;
        }