From mboxrd@z Thu Jan 1 00:00:00 1970 From: nicolas.ferre@atmel.com (Nicolas Ferre) Date: Wed, 31 Oct 2012 10:59:24 +0100 Subject: [PATCH v3 06/10] net/macb: clean up ring buffer logic In-Reply-To: References: <75eb5df193c504e68ebff7d6a6a88d9a1cc678cb.1351591858.git.nicolas.ferre@atmel.com> Message-ID: <5090F67C.9020104@atmel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10/30/2012 07:22 PM, H?vard Skinnemoen : > On Tue, Oct 30, 2012 at 4:12 AM, David Laight wrote: >>> Instead of masking head and tail every time we increment them, just let them >>> wrap through UINT_MAX and mask them when subscripting. Add simple accessor >>> functions to do the subscripting properly to minimize the chances of messing >>> this up. >> ... >>> +static unsigned int macb_tx_ring_avail(struct macb *bp) >>> +{ >>> + return TX_RING_SIZE - (bp->tx_head - bp->tx_tail); >>> +} >> >> That one doesn't look quite right to me. >> Surely it should be masking with 'TX_RING_SIZE - 1' > > Why is that? head and tail can never be more than TX_RING_SIZE apart, > so it shouldn't make any difference. Absolutely. Best regards, -- Nicolas Ferre