From: Kevin Laatz <kevin.laatz@intel.com>
Date: Tue, 27 Aug 2019 02:25:29 +0000
Subject: samples/bpf: add buffer recycling for unaligned chunks to xdpsock
Patch-mainline: v5.4-rc1
Git-commit: 03895e63ff97447e5eab1b71ed46e3662a45bfe8
References: bsc#1155518

This patch adds buffer recycling support for unaligned buffers. Since we
don't mask the addr to 2k at umem_reg in unaligned mode, we need to make
sure we give back the correct (original) addr to the fill queue. We achieve
this using the new descriptor format and associated masks. The new format
uses the upper 16-bits for the offset and the lower 48-bits for the addr.
Since we have a field for the offset, we no longer need to modify the
actual address. As such, all we have to do to get back the original address
is mask for the lower 48 bits (i.e. strip the offset and we get the address
on it's own).

Signed-off-by: Kevin Laatz <kevin.laatz@intel.com>
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Gary Lin <glin@suse.com>
---
 samples/bpf/xdpsock_user.c |   26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c
@@ -484,6 +484,7 @@ static void kick_tx(struct xsk_socket_in
 static inline void complete_tx_l2fwd(struct xsk_socket_info *xsk,
 				     struct pollfd *fds)
 {
+	struct xsk_umem_info *umem = xsk->umem;
 	u32 idx_cq = 0, idx_fq = 0;
 	unsigned int rcvd;
 	size_t ndescs;
@@ -498,24 +499,23 @@ static inline void complete_tx_l2fwd(str
 		xsk->outstanding_tx;
 
 	/* re-add completed Tx buffers */
-	rcvd = xsk_ring_cons__peek(&xsk->umem->cq, ndescs, &idx_cq);
+	rcvd = xsk_ring_cons__peek(&umem->cq, ndescs, &idx_cq);
 	if (rcvd > 0) {
 		unsigned int i;
 		int ret;
 
-		ret = xsk_ring_prod__reserve(&xsk->umem->fq, rcvd, &idx_fq);
+		ret = xsk_ring_prod__reserve(&umem->fq, rcvd, &idx_fq);
 		while (ret != rcvd) {
 			if (ret < 0)
 				exit_with_error(-ret);
-			if (xsk_ring_prod__needs_wakeup(&xsk->umem->fq))
+			if (xsk_ring_prod__needs_wakeup(&umem->fq))
 				ret = poll(fds, num_socks, opt_timeout);
-			ret = xsk_ring_prod__reserve(&xsk->umem->fq, rcvd,
-						     &idx_fq);
+			ret = xsk_ring_prod__reserve(&umem->fq, rcvd, &idx_fq);
 		}
+
 		for (i = 0; i < rcvd; i++)
-			*xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) =
-				*xsk_ring_cons__comp_addr(&xsk->umem->cq,
-							  idx_cq++);
+			*xsk_ring_prod__fill_addr(&umem->fq, idx_fq++) =
+				*xsk_ring_cons__comp_addr(&umem->cq, idx_cq++);
 
 		xsk_ring_prod__submit(&xsk->umem->fq, rcvd);
 		xsk_ring_cons__release(&xsk->umem->cq, rcvd);
@@ -568,10 +568,13 @@ static void rx_drop(struct xsk_socket_in
 	for (i = 0; i < rcvd; i++) {
 		u64 addr = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx)->addr;
 		u32 len = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx++)->len;
+		u64 orig = xsk_umem__extract_addr(addr);
+
+		addr = xsk_umem__add_offset_to_addr(addr);
 		char *pkt = xsk_umem__get_data(xsk->umem->buffer, addr);
 
 		hex_dump(pkt, len, addr);
-		*xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) = addr;
+		*xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) = orig;
 	}
 
 	xsk_ring_prod__submit(&xsk->umem->fq, rcvd);
@@ -680,12 +683,15 @@ static void l2fwd(struct xsk_socket_info
 	for (i = 0; i < rcvd; i++) {
 		u64 addr = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx)->addr;
 		u32 len = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx++)->len;
+		u64 orig = xsk_umem__extract_addr(addr);
+
+		addr = xsk_umem__add_offset_to_addr(addr);
 		char *pkt = xsk_umem__get_data(xsk->umem->buffer, addr);
 
 		swap_mac_addresses(pkt);
 
 		hex_dump(pkt, len, addr);
-		xsk_ring_prod__tx_desc(&xsk->tx, idx_tx)->addr = addr;
+		xsk_ring_prod__tx_desc(&xsk->tx, idx_tx)->addr = orig;
 		xsk_ring_prod__tx_desc(&xsk->tx, idx_tx++)->len = len;
 	}