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Commit 6044735d authored by Eilon Greenstein's avatar Eilon Greenstein Committed by David S. Miller
Browse files

bnx2x: Reduce the likelihood of smb_mb 



As the comment explains, this smb_mb is needed only if the queue is stopped
(which is unlikely) so the barrier can be moved to that location

Signed-off-by: default avatarEilon Greenstein <eilong@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0d1a8d2d

drivers/net/bnx2x_main.c

+8 −7
Original line number Original line Diff line number Diff line
@@ -916,18 +916,19 @@ static void bnx2x_tx_int(struct bnx2x_fastpath *fp, int work) 
	fp->tx_pkt_cons = sw_cons;

	fp->tx_pkt_cons = sw_cons;

	fp->tx_bd_cons = bd_cons;

	fp->tx_bd_cons = bd_cons;





	/* Need to make the tx_bd_cons update visible to start_xmit()

	 * before checking for netif_tx_queue_stopped().  Without the

	 * memory barrier, there is a small possibility that start_xmit()

	 * will miss it and cause the queue to be stopped forever.

	 */

	smp_mb();



	/* TBD need a thresh? */

	/* TBD need a thresh? */

	if (unlikely(netif_tx_queue_stopped(txq))) {

	if (unlikely(netif_tx_queue_stopped(txq))) {





		__netif_tx_lock(txq, smp_processor_id());

		__netif_tx_lock(txq, smp_processor_id());





		/* Need to make the tx_bd_cons update visible to start_xmit()

		 * before checking for netif_tx_queue_stopped().  Without the

		 * memory barrier, there is a small possibility that

		 * start_xmit() will miss it and cause the queue to be stopped

		 * forever.

		 */

		smp_mb();



		if ((netif_tx_queue_stopped(txq)) &&

		if ((netif_tx_queue_stopped(txq)) &&

		    (bp->state == BNX2X_STATE_OPEN) &&

		    (bp->state == BNX2X_STATE_OPEN) &&

		    (bnx2x_tx_avail(fp) >= MAX_SKB_FRAGS + 3))

		    (bnx2x_tx_avail(fp) >= MAX_SKB_FRAGS + 3))