[PATCH v2 bpf-next 3/6] xsk: get rid of xdp_buff_xsk::orig_addr

[Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>]

Continue the process of dieting xdp_buff_xsk by removing orig_addr
member. It can be calculated from xdp->data_hard_start where it was
previously used, so it is not anything that has to be carried around in
struct used widely in hot path.

This has been used for initializing xdp_buff_xsk::frame_dma during pool
setup and as a shortcut in xp_get_handle() to retrieve address provided
to xsk Rx queue.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
---
 include/net/xsk_buff_pool.h | 19 +++++++++++--------
 net/xdp/xsk.c               |  2 +-
 net/xdp/xsk_buff_pool.c     |  4 +++-
 3 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index af8b6f776f86..468a23b1b4c5 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -28,7 +28,6 @@ struct xdp_buff_xsk {
 	dma_addr_t dma;
 	dma_addr_t frame_dma;
 	struct xsk_buff_pool *pool;
-	u64 orig_addr;
 	struct list_head list_node;
 };
 
@@ -119,7 +118,6 @@ void xp_free(struct xdp_buff_xsk *xskb);
 static inline void xp_init_xskb_addr(struct xdp_buff_xsk *xskb, struct xsk_buff_pool *pool,
 				     u64 addr)
 {
-	xskb->orig_addr = addr;
 	xskb->xdp.data_hard_start = pool->addrs + addr + pool->headroom;
 }
 
@@ -221,14 +219,19 @@ static inline void xp_release(struct xdp_buff_xsk *xskb)
 		xskb->pool->free_heads[xskb->pool->free_heads_cnt++] = xskb;
 }
 
-static inline u64 xp_get_handle(struct xdp_buff_xsk *xskb)
+static inline u64 xp_get_handle(struct xdp_buff_xsk *xskb,
+				struct xsk_buff_pool *pool)
 {
-	u64 offset = xskb->xdp.data - xskb->xdp.data_hard_start;
+	u64 orig_addr = xskb->xdp.data - pool->addrs;
+	u64 offset;
 
-	offset += xskb->pool->headroom;
-	if (!xskb->pool->unaligned)
-		return xskb->orig_addr + offset;
-	return xskb->orig_addr + (offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT);
+	if (!pool->unaligned)
+		return orig_addr;
+
+	offset = xskb->xdp.data - xskb->xdp.data_hard_start;
+	orig_addr -= offset;
+	offset += pool->headroom;
+	return orig_addr + (offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT);
 }
 
 static inline bool xp_tx_metadata_enabled(const struct xsk_buff_pool *pool)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 520023405908..6c31c1de1619 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -141,7 +141,7 @@ static int __xsk_rcv_zc(struct xdp_sock *xs, struct xdp_buff_xsk *xskb, u32 len,
 	u64 addr;
 	int err;
 
-	addr = xp_get_handle(xskb);
+	addr = xp_get_handle(xskb, xskb->pool);
 	err = xskq_prod_reserve_desc(xs->rx, addr, len, flags);
 	if (err) {
 		xs->rx_queue_full++;
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 973557d5e4f7..7ecd4ccd2473 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -416,8 +416,10 @@ static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_
 
 		for (i = 0; i < pool->heads_cnt; i++) {
 			struct xdp_buff_xsk *xskb = &pool->heads[i];
+			u64 orig_addr;
 
-			xp_init_xskb_dma(xskb, pool, dma_map->dma_pages, xskb->orig_addr);
+			orig_addr = xskb->xdp.data_hard_start - pool->addrs - pool->headroom;
+			xp_init_xskb_dma(xskb, pool, dma_map->dma_pages, orig_addr);
 		}
 	}
 
-- 
2.34.1