From: Magnus Karlsson <magnus.karlsson@intel.com>
Date: Fri, 31 Aug 2018 13:40:01 +0200
Subject: i40e: fix possible compiler warning in xsk TX path
Patch-mainline: v4.20-rc1
Git-commit: cf484f9f91f702e61eb47f7b142de6edc33a4a88
References: bsc#1111981 FATE#326312 FATE#326313

With certain gcc versions, it was possible to get the warning
"'tx_desc' may be used uninitialized in this function" for the
i40e_xmit_zc. This was not possible, however this commit simplifies
the code path so that this warning is no longer emitted.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/i40e/i40e_xsk.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c
@@ -668,9 +668,8 @@ int i40e_clean_rx_irq_zc(struct i40e_rin
  **/
 static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget)
 {
-	unsigned int total_packets = 0;
+	struct i40e_tx_desc *tx_desc = NULL;
 	struct i40e_tx_buffer *tx_bi;
-	struct i40e_tx_desc *tx_desc;
 	bool work_done = true;
 	dma_addr_t dma;
 	u32 len;
@@ -697,14 +696,13 @@ static bool i40e_xmit_zc(struct i40e_rin
 			build_ctob(I40E_TX_DESC_CMD_ICRC
 				   | I40E_TX_DESC_CMD_EOP,
 				   0, len, 0);
-		total_packets++;
 
 		xdp_ring->next_to_use++;
 		if (xdp_ring->next_to_use == xdp_ring->count)
 			xdp_ring->next_to_use = 0;
 	}
 
-	if (total_packets > 0) {
+	if (tx_desc) {
 		/* Request an interrupt for the last frame and bump tail ptr. */
 		tx_desc->cmd_type_offset_bsz |= (I40E_TX_DESC_CMD_RS <<
 						 I40E_TXD_QW1_CMD_SHIFT);