ice: Pull out next_to_clean bump out of ice_put_rx_buf()

Plan is to move ice_put_rx_buf() to the end of ice_clean_rx_irq() so
in order to keep the ability of walking through HW Rx descriptors, pull
out next_to_clean handling out of ice_put_rx_buf().
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Link: https://lore.kernel.org/bpf/20230131204506.219292-5-maciej.fijalkowski@intel.com

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

@@ -898,11 +898,12 @@ ice_reuse_rx_page(struct ice_rx_ring *rx_ring, struct ice_rx_buf *old_buf)
  * for use by the CPU.
  */
 static struct ice_rx_buf *
-ice_get_rx_buf(struct ice_rx_ring *rx_ring, const unsigned int size)
+ice_get_rx_buf(struct ice_rx_ring *rx_ring, const unsigned int size,
+	       const unsigned int ntc)
 {
 	struct ice_rx_buf *rx_buf;
 
-	rx_buf = &rx_ring->rx_buf[rx_ring->next_to_clean];
+	rx_buf = &rx_ring->rx_buf[ntc];
 	rx_buf->pgcnt =
 #if (PAGE_SIZE < 8192)
 		page_count(rx_buf->page);
@@ -1040,19 +1041,12 @@ ice_construct_skb(struct ice_rx_ring *rx_ring, struct ice_rx_buf *rx_buf,
  * @rx_ring: Rx descriptor ring to transact packets on
  * @rx_buf: Rx buffer to pull data from
  *
- * This function will update next_to_clean and then clean up the contents
- * of the rx_buf. It will either recycle the buffer or unmap it and free
- * the associated resources.
+ * This function will clean up the contents of the rx_buf. It will either
+ * recycle the buffer or unmap it and free the associated resources.
  */
 static void
 ice_put_rx_buf(struct ice_rx_ring *rx_ring, struct ice_rx_buf *rx_buf)
 {
-	u16 ntc = rx_ring->next_to_clean + 1;
-
-	/* fetch, update, and store next to clean */
-	ntc = (ntc < rx_ring->count) ? ntc : 0;
-	rx_ring->next_to_clean = ntc;
-
 	if (!rx_buf)
 		return;
 
@@ -1114,6 +1108,8 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 	unsigned int xdp_res, xdp_xmit = 0;
 	struct sk_buff *skb = rx_ring->skb;
 	struct bpf_prog *xdp_prog = NULL;
+	u32 ntc = rx_ring->next_to_clean;
+	u32 cnt = rx_ring->count;
 	bool failure;
 
 	/* Frame size depend on rx_ring setup when PAGE_SIZE=4K */
@@ -1136,7 +1132,7 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 		u16 rx_ptype;
 
 		/* get the Rx desc from Rx ring based on 'next_to_clean' */
-		rx_desc = ICE_RX_DESC(rx_ring, rx_ring->next_to_clean);
+		rx_desc = ICE_RX_DESC(rx_ring, ntc);
 
 		/* status_error_len will always be zero for unused descriptors
 		 * because it's cleared in cleanup, and overlaps with hdr_addr
@@ -1160,6 +1156,8 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 			if (rx_desc->wb.rxdid == FDIR_DESC_RXDID &&
 			    ctrl_vsi->vf)
 				ice_vc_fdir_irq_handler(ctrl_vsi, rx_desc);
+			if (++ntc == cnt)
+				ntc = 0;
 			ice_put_rx_buf(rx_ring, NULL);
 			cleaned_count++;
 			continue;
@@ -1169,7 +1167,7 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 			ICE_RX_FLX_DESC_PKT_LEN_M;
 
 		/* retrieve a buffer from the ring */
-		rx_buf = ice_get_rx_buf(rx_ring, size);
+		rx_buf = ice_get_rx_buf(rx_ring, size, ntc);
 
 		if (!size) {
 			xdp->data = NULL;
@@ -1203,6 +1201,8 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 		total_rx_pkts++;
 
 		cleaned_count++;
+		if (++ntc == cnt)
+			ntc = 0;
 		ice_put_rx_buf(rx_ring, rx_buf);
 		continue;
 construct_skb:
@@ -1222,6 +1222,8 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 			break;
 		}
 
+		if (++ntc == cnt)
+			ntc = 0;
 		ice_put_rx_buf(rx_ring, rx_buf);
 		cleaned_count++;
 
@@ -1262,6 +1264,7 @@ int ice_clean_rx_irq(struct ice_rx_ring *rx_ring, int budget)
 		total_rx_pkts++;
 	}
 
+	rx_ring->next_to_clean = ntc;
 	/* return up to cleaned_count buffers to hardware */
 	failure = ice_alloc_rx_bufs(rx_ring, cleaned_count);