1 files changed, 46 insertions, 56 deletions

diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 8bfa2ee6864c..1436116767ea 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -34,8 +34,7 @@ struct xsk_queue {
 	u32 ring_mask;
 	u32 nentries;
 	u32 cached_prod;
-	u32 cons_head;
-	u32 cons_tail;
+	u32 cached_cons;
 	struct xdp_ring *ring;
 	u64 invalid_descs;
 };
@@ -89,43 +88,48 @@ static inline u64 xskq_nb_invalid_descs(struct xsk_queue *q)
 	return q ? q->invalid_descs : 0;
 }
 
-static inline u32 xskq_nb_avail(struct xsk_queue *q)
+static inline void __xskq_cons_release(struct xsk_queue *q)
 {
-	u32 entries = q->cached_prod - q->cons_tail;
+	smp_mb(); /* D, matches A */
+	WRITE_ONCE(q->ring->consumer, q->cached_cons);
+}
 
-	if (entries == 0) {
-		/* Refresh the local pointer */
-		q->cached_prod = READ_ONCE(q->ring->producer);
-		entries = q->cached_prod - q->cons_tail;
-	}
+static inline void __xskq_cons_peek(struct xsk_queue *q)
+{
+	/* Refresh the local pointer */
+	q->cached_prod = READ_ONCE(q->ring->producer);
+	smp_rmb(); /* C, matches B */
+}
 
-	return entries;
+static inline void xskq_cons_get_entries(struct xsk_queue *q)
+{
+	__xskq_cons_release(q);
+	__xskq_cons_peek(q);
 }
 
 static inline bool xskq_prod_is_full(struct xsk_queue *q)
 {
-	u32 free_entries = q->nentries - (q->cached_prod - q->cons_tail);
+	u32 free_entries = q->nentries - (q->cached_prod - q->cached_cons);
 
 	if (free_entries)
 		return false;
 
 	/* Refresh the local tail pointer */
-	q->cons_tail = READ_ONCE(q->ring->consumer);
-	free_entries = q->nentries - (q->cached_prod - q->cons_tail);
+	q->cached_cons = READ_ONCE(q->ring->consumer);
+	free_entries = q->nentries - (q->cached_prod - q->cached_cons);
 
 	return !free_entries;
 }
 
-static inline bool xskq_has_addrs(struct xsk_queue *q, u32 cnt)
+static inline bool xskq_cons_has_entries(struct xsk_queue *q, u32 cnt)
 {
-	u32 entries = q->cached_prod - q->cons_tail;
+	u32 entries = q->cached_prod - q->cached_cons;
 
 	if (entries >= cnt)
 		return true;
 
-	/* Refresh the local pointer. */
-	q->cached_prod = READ_ONCE(q->ring->producer);
-	entries = q->cached_prod - q->cons_tail;
+	__xskq_cons_peek(q);
+	entries = q->cached_prod - q->cached_cons;
 
 	return entries >= cnt;
 }
@@ -172,9 +176,10 @@ static inline bool xskq_is_valid_addr_unaligned(struct xsk_queue *q, u64 addr,
 static inline u64 *xskq_validate_addr(struct xsk_queue *q, u64 *addr,
 				      struct xdp_umem *umem)
 {
-	while (q->cons_tail != q->cons_head) {
-		struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
-		unsigned int idx = q->cons_tail & q->ring_mask;
+	struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
+
+	while (q->cached_cons != q->cached_prod) {
+		u32 idx = q->cached_cons & q->ring_mask;
 
 		*addr = READ_ONCE(ring->desc[idx]) & q->chunk_mask;
 
@@ -190,30 +195,27 @@ static inline u64 *xskq_validate_addr(struct xsk_queue *q, u64 *addr,
 			return addr;
 
 out:
-		q->cons_tail++;
+		q->cached_cons++;
 	}
 
 	return NULL;
 }
 
-static inline u64 *xskq_peek_addr(struct xsk_queue *q, u64 *addr,
-				  struct xdp_umem *umem)
+static inline u64 *xskq_cons_peek_addr(struct xsk_queue *q, u64 *addr,
+				       struct xdp_umem *umem)
 {
-	if (q->cons_tail == q->cons_head) {
-		smp_mb(); /* D, matches A */
-		WRITE_ONCE(q->ring->consumer, q->cons_tail);
-		q->cons_head = q->cons_tail + xskq_nb_avail(q);
-
-		/* Order consumer and data */
-		smp_rmb();
-	}
-
+	if (q->cached_prod == q->cached_cons)
+		xskq_cons_get_entries(q);
 	return xskq_validate_addr(q, addr, umem);
 }
 
-static inline void xskq_discard_addr(struct xsk_queue *q)
+static inline void xskq_cons_release(struct xsk_queue *q)
 {
-	q->cons_tail++;
+	/* To improve performance, only update local state here.
+	 * Do the actual release operation when we get new entries
+	 * from the ring in xskq_cons_get_entries() instead.
+	 */
+	q->cached_cons++;
 }
 
 static inline int xskq_prod_reserve(struct xsk_queue *q)
@@ -299,41 +301,29 @@ static inline struct xdp_desc *xskq_validate_desc(struct xsk_queue *q,
 						  struct xdp_desc *desc,
 						  struct xdp_umem *umem)
 {
-	while (q->cons_tail != q->cons_head) {
+	while (q->cached_cons != q->cached_prod) {
 		struct xdp_rxtx_ring *ring = (struct xdp_rxtx_ring *)q->ring;
-		unsigned int idx = q->cons_tail & q->ring_mask;
+		u32 idx = q->cached_cons & q->ring_mask;
 
 		*desc = READ_ONCE(ring->desc[idx]);
 		if (xskq_is_valid_desc(q, desc, umem))
 			return desc;
 
-		q->cons_tail++;
+		q->cached_cons++;
 	}
 
 	return NULL;
 }
 
-static inline struct xdp_desc *xskq_peek_desc(struct xsk_queue *q,
-					      struct xdp_desc *desc,
-					      struct xdp_umem *umem)
+static inline struct xdp_desc *xskq_cons_peek_desc(struct xsk_queue *q,
+						   struct xdp_desc *desc,
+						   struct xdp_umem *umem)
 {
-	if (q->cons_tail == q->cons_head) {
-		smp_mb(); /* D, matches A */
-		WRITE_ONCE(q->ring->consumer, q->cons_tail);
-		q->cons_head = q->cons_tail + xskq_nb_avail(q);
-
-		/* Order consumer and data */
-		smp_rmb(); /* C, matches B */
-	}
-
+	if (q->cached_prod == q->cached_cons)
+		xskq_cons_get_entries(q);
 	return xskq_validate_desc(q, desc, umem);
 }
 
-static inline void xskq_discard_desc(struct xsk_queue *q)
-{
-	q->cons_tail++;
-}
-
 static inline int xskq_prod_reserve_desc(struct xsk_queue *q,
 					 u64 addr, u32 len)
 {
@@ -351,7 +341,7 @@ static inline int xskq_prod_reserve_desc(struct xsk_queue *q,
 	return 0;
 }
 
-static inline bool xskq_full_desc(struct xsk_queue *q)
+static inline bool xskq_cons_is_full(struct xsk_queue *q)
 {
 	/* No barriers needed since data is not accessed */
 	return READ_ONCE(q->ring->producer) - READ_ONCE(q->ring->consumer) ==