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 <redacted>
Signed-off-by: Bruce Richardson <redacted>

---
v2:
  - Removed unused defines
  - Fix buffer recycling for unaligned case
  - Remove --buf-size (--frame-size merged before this)
  - Modifications to use the new descriptor format for buffer 
recycling
---
 samples/bpf/xdpsock_user.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/samples/bpf/xdpsock_user.c b/samples/bpf/xdpsock_user.c
index 756b00eb1afe..62b2059cd0e3 100644
--- a/samples/bpf/xdpsock_user.c
+++ b/samples/bpf/xdpsock_user.c

@@ -475,6 +475,7 @@ static void kick_tx(struct xsk_socket_info *xsk)

 static inline void complete_tx_l2fwd(struct xsk_socket_info *xsk)
 {
+	struct xsk_umem_info *umem = xsk->umem;
 	u32 idx_cq = 0, idx_fq = 0;
 	unsigned int rcvd;
 	size_t ndescs;

@@ -487,22 +488,21 @@ static inline void complete_tx_l2fwd(struct 

xsk_socket_info *xsk)
 		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);
-			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);

@@ -549,7 +549,11 @@ static void rx_drop(struct xsk_socket_info *xsk)
 	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;
-		char *pkt = xsk_umem__get_data(xsk->umem->buffer, addr);
+		u64 offset = addr >> XSK_UNALIGNED_BUF_OFFSET_SHIFT;
+
+		addr &= XSK_UNALIGNED_BUF_ADDR_MASK;
+		char *pkt = xsk_umem__get_data(xsk->umem->buffer,
+				addr + offset);

 		hex_dump(pkt, len, addr);
 		*xsk_ring_prod__fill_addr(&xsk->umem->fq, idx_fq++) = addr;

@@ -655,7 +659,9 @@ static void l2fwd(struct xsk_socket_info *xsk)
 							  idx_rx)->addr;
 			u32 len = xsk_ring_cons__rx_desc(&xsk->rx,
 							 idx_rx++)->len;
-			char *pkt = xsk_umem__get_data(xsk->umem->buffer, addr);
+			u64 offset = addr >> XSK_UNALIGNED_BUF_OFFSET_SHIFT;
+			char *pkt = xsk_umem__get_data(xsk->umem->buffer,
+				(addr & XSK_UNALIGNED_BUF_ADDR_MASK) + offset);

 			swap_mac_addresses(pkt);

-- 
2.17.1