From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yegor Yefremov Subject: Re: [PATCH 1/1] KS8695: update ksp->next_rx_desc_read at the end of rx loop Date: Wed, 17 Mar 2010 10:40:10 +0100 Message-ID: References: <1268754720.3094.55.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: netdev , davem@davemloft.net To: Eric Dumazet Return-path: Received: from mail-ew0-f220.google.com ([209.85.219.220]:43940 "EHLO mail-ew0-f220.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753860Ab0CQJkM (ORCPT ); Wed, 17 Mar 2010 05:40:12 -0400 Received: by ewy20 with SMTP id 20so308737ewy.1 for ; Wed, 17 Mar 2010 02:40:10 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: KS8695: update ksp->next_rx_desc_read at the end of rx loop There is no need to adjust the next rx descriptor after each packet, so do it only once at the end of the routine. Signed-off-by: Eric Dumazet Signed-off-by: Yegor Yefremov Index: linux-2.6.34-rc1/drivers/net/arm/ks8695net.c =================================================================== --- linux-2.6.34-rc1.orig/drivers/net/arm/ks8695net.c +++ linux-2.6.34-rc1/drivers/net/arm/ks8695net.c @@ -449,11 +449,10 @@ ks8695_rx_irq(int irq, void *dev_id) } /** - * ks8695_rx - Receive packets called by NAPI poll method + * ks8695_rx - Receive packets called by NAPI poll method * @ksp: Private data for the KS8695 Ethernet - * @budget: The max packets would be receive + * @budget: Number of packets allowed to process */ - static int ks8695_rx(struct ks8695_priv *ksp, int budget) { struct net_device *ndev = ksp->ndev; @@ -461,7 +460,6 @@ static int ks8695_rx(struct ks8695_priv int buff_n; u32 flags; int pktlen; - int last_rx_processed = -1; int received = 0; buff_n = ksp->next_rx_desc_read; @@ -471,6 +469,7 @@ static int ks8695_rx(struct ks8695_priv cpu_to_le32(RDES_OWN)))) { rmb(); flags = le32_to_cpu(ksp->rx_ring[buff_n].status); + /* Found an SKB which we own, this means we * received a packet */ @@ -533,23 +532,18 @@ rx_failure: ksp->rx_ring[buff_n].status = cpu_to_le32(RDES_OWN); rx_finished: received++; - /* And note this as processed so we can start - * from here next time - */ - last_rx_processed = buff_n; buff_n = (buff_n + 1) & MAX_RX_DESC_MASK; - /*And note which RX descriptor we last did */ - if (likely(last_rx_processed != -1)) - ksp->next_rx_desc_read = - (last_rx_processed + 1) & - MAX_RX_DESC_MASK; } + + /* And note which RX descriptor we last did */ + ksp->next_rx_desc_read = buff_n; + /* And refill the buffers */ ks8695_refill_rxbuffers(ksp); - /* Kick the RX DMA engine, in case it became - * suspended */ + /* Kick the RX DMA engine, in case it became suspended */ ks8695_writereg(ksp, KS8695_DRSC, 0); + return received; }