xsk: make xsk_buff_add_frag() really add the frag via __xdp_buff_add_frag()

Currently, xsk_buff_add_frag() only adds the frag to pool's linked list,
not doing anything with the &xdp_buff. The drivers do that manually and
the logic is the same.
Make it really add an skb frag, just like xdp_buff_add_frag() does that,
and freeing frags on error if needed. This allows to remove repeating
code from i40e and ice and not add the same code again and again.

Acked-by: Maciej Fijalkowski <[email protected]>
Signed-off-by: Alexander Lobakin <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: alobakin

drivers/net/ethernet/intel/i40e/i40e_xsk.c

@@ -395,32 +395,6 @@ static void i40e_handle_xdp_result_zc(struct i40e_ring *rx_ring,
 	WARN_ON_ONCE(1);
 }
 
-static int
-i40e_add_xsk_frag(struct i40e_ring *rx_ring, struct xdp_buff *first,
-		  struct xdp_buff *xdp, const unsigned int size)
-{
-	struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(first);
-
-	if (!xdp_buff_has_frags(first)) {
-		sinfo->nr_frags = 0;
-		sinfo->xdp_frags_size = 0;
-		xdp_buff_set_frags_flag(first);
-	}
-
-	if (unlikely(sinfo->nr_frags == MAX_SKB_FRAGS)) {
-		xsk_buff_free(first);
-		return -ENOMEM;
-	}
-
-	__skb_fill_page_desc_noacc(sinfo, sinfo->nr_frags++,
-				   virt_to_page(xdp->data_hard_start),
-				   XDP_PACKET_HEADROOM, size);
-	sinfo->xdp_frags_size += size;
-	xsk_buff_add_frag(xdp);
-
-	return 0;
-}
-
 /**
  * i40e_clean_rx_irq_zc - Consumes Rx packets from the hardware ring
  * @rx_ring: Rx ring
@@ -486,8 +460,10 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
 
 		if (!first)
 			first = bi;
-		else if (i40e_add_xsk_frag(rx_ring, first, bi, size))
+		else if (!xsk_buff_add_frag(first, bi)) {
+			xsk_buff_free(first);
 			break;
+		}
 
 		if (++next_to_process == count)
 			next_to_process = 0;

drivers/net/ethernet/intel/ice/ice_xsk.c

@@ -801,35 +801,6 @@ ice_run_xdp_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
 	return result;
 }
 
-static int
-ice_add_xsk_frag(struct ice_rx_ring *rx_ring, struct xdp_buff *first,
-		 struct xdp_buff *xdp, const unsigned int size)
-{
-	struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(first);
-
-	if (!size)
-		return 0;
-
-	if (!xdp_buff_has_frags(first)) {
-		sinfo->nr_frags = 0;
-		sinfo->xdp_frags_size = 0;
-		xdp_buff_set_frags_flag(first);
-	}
-
-	if (unlikely(sinfo->nr_frags == MAX_SKB_FRAGS)) {
-		xsk_buff_free(first);
-		return -ENOMEM;
-	}
-
-	__skb_fill_page_desc_noacc(sinfo, sinfo->nr_frags++,
-				   virt_to_page(xdp->data_hard_start),
-				   XDP_PACKET_HEADROOM, size);
-	sinfo->xdp_frags_size += size;
-	xsk_buff_add_frag(xdp);
-
-	return 0;
-}
-
 /**
  * ice_clean_rx_irq_zc - consumes packets from the hardware ring
  * @rx_ring: AF_XDP Rx ring
@@ -895,7 +866,8 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring,
 
 		if (!first) {
 			first = xdp;
-		} else if (ice_add_xsk_frag(rx_ring, first, xdp, size)) {
+		} else if (likely(size) && !xsk_buff_add_frag(first, xdp)) {
+			xsk_buff_free(first);
 			break;
 		}
 

include/net/xdp_sock_drv.h

@@ -136,11 +136,21 @@ static inline void xsk_buff_free(struct xdp_buff *xdp)
 	xp_free(xskb);
 }
 
-static inline void xsk_buff_add_frag(struct xdp_buff *xdp)
+static inline bool xsk_buff_add_frag(struct xdp_buff *head,
+				     struct xdp_buff *xdp)
 {
-	struct xdp_buff_xsk *frag = container_of(xdp, struct xdp_buff_xsk, xdp);
+	const void *data = xdp->data;
+	struct xdp_buff_xsk *frag;
+
+	if (!__xdp_buff_add_frag(head, virt_to_netmem(data),
+				 offset_in_page(data), xdp->data_end - data,
+				 xdp->frame_sz, false))
+		return false;
 
+	frag = container_of(xdp, struct xdp_buff_xsk, xdp);
 	list_add_tail(&frag->list_node, &frag->pool->xskb_list);
+
+	return true;
 }
 
 static inline struct xdp_buff *xsk_buff_get_frag(const struct xdp_buff *first)
@@ -357,8 +367,10 @@ static inline void xsk_buff_free(struct xdp_buff *xdp)
 {
 }
 
-static inline void xsk_buff_add_frag(struct xdp_buff *xdp)
+static inline bool xsk_buff_add_frag(struct xdp_buff *head,
+				     struct xdp_buff *xdp)
 {
+	return false;
 }
 
 static inline struct xdp_buff *xsk_buff_get_frag(const struct xdp_buff *first)