ice: xsk: Fix cleaning of XDP_TX frames

Incrementation of xsk_frames inside the for-loop produces
infinite loop, if we have both normal AF_XDP-TX and XDP_TXed
buffers to complete.

Split xsk_frames into 2 variables (xsk_frames and completed_frames)
to eliminate this bug.

Fixes: 2932279 ("ice: xsk: change batched Tx descriptor cleaning")
Acked-by: Maciej Fijalkowski <[email protected]>
Signed-off-by: Larysa Zaremba <[email protected]>
Reviewed-by: Alexander Duyck <[email protected]>
Acked-by: Tony Nguyen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: walking-machine

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

@@ -800,6 +800,7 @@ static void ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring)
 	struct ice_tx_desc *tx_desc;
 	u16 cnt = xdp_ring->count;
 	struct ice_tx_buf *tx_buf;
+	u16 completed_frames = 0;
 	u16 xsk_frames = 0;
 	u16 last_rs;
 	int i;
@@ -809,19 +810,21 @@ static void ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring)
 	if ((tx_desc->cmd_type_offset_bsz &
 	    cpu_to_le64(ICE_TX_DESC_DTYPE_DESC_DONE))) {
 		if (last_rs >= ntc)
-			xsk_frames = last_rs - ntc + 1;
+			completed_frames = last_rs - ntc + 1;
 		else
-			xsk_frames = last_rs + cnt - ntc + 1;
+			completed_frames = last_rs + cnt - ntc + 1;
 	}
 
-	if (!xsk_frames)
+	if (!completed_frames)
 		return;
 
-	if (likely(!xdp_ring->xdp_tx_active))
+	if (likely(!xdp_ring->xdp_tx_active)) {
+		xsk_frames = completed_frames;
 		goto skip;
+	}
 
 	ntc = xdp_ring->next_to_clean;
-	for (i = 0; i < xsk_frames; i++) {
+	for (i = 0; i < completed_frames; i++) {
 		tx_buf = &xdp_ring->tx_buf[ntc];
 
 		if (tx_buf->raw_buf) {
@@ -837,7 +840,7 @@ static void ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring)
 	}
 skip:
 	tx_desc->cmd_type_offset_bsz = 0;
-	xdp_ring->next_to_clean += xsk_frames;
+	xdp_ring->next_to_clean += completed_frames;
 	if (xdp_ring->next_to_clean >= cnt)
 		xdp_ring->next_to_clean -= cnt;
 	if (xsk_frames)