From mboxrd@z Thu Jan 1 00:00:00 1970 From: u.kleine-koenig@pengutronix.de (Uwe =?iso-8859-1?Q?Kleine-K=F6nig?=) Date: Mon, 27 Apr 2015 08:56:57 +0200 Subject: [PATCH 3/4] mtd: mxc_nand: fix truncate of unaligned oob copying In-Reply-To: <20150427044618.GS2258@tarshish> References: <1f8e85fd8e75170e1005473c075942cb3d4479fe.1430034929.git.baruch@tkos.co.il> <20150426195211.GB19431@pengutronix.de> <20150427044618.GS2258@tarshish> Message-ID: <20150427065657.GD19431@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello Baruch, On Mon, Apr 27, 2015 at 07:46:18AM +0300, Baruch Siach wrote: > On Sun, Apr 26, 2015 at 09:52:11PM +0200, Uwe Kleine-K?nig wrote: > > On Sun, Apr 26, 2015 at 11:16:50AM +0300, Baruch Siach wrote: > > > diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c > > > index c650f0950b20..c05f5e8fef17 100644 > > > --- a/drivers/mtd/nand/mxc_nand.c > > > +++ b/drivers/mtd/nand/mxc_nand.c > > > @@ -840,22 +840,22 @@ static void copy_spare(struct mtd_info *mtd, bool bfrom) > > > for (i = 0; i < num_chunks - 1; i++) > > > memcpy32_fromio(d + i * oob_chunk_size, > > > s + i * sparebuf_size, > > > - oob_chunk_size); > > > + ALIGN(oob_chunk_size, 4)); > > If oob_chunk_size isn't 32-bit-aligned, d + i * oob_chunk_size isn't > > either for uneven i. That's not nice. I suggest to use memcpy16_fromio. > > memcpy32_fromio() was introduced by Sascha in 096bcc231fd2 (mtd: mxc_nand: use > 32bit copy functions, 2012-05-29), replacing memcpy_fromio() to force 32bit io > access. Are you sure the hypothetical memcpy16_fromio() would work? according to the reference manual you can use 16-bit or 32-bit accesses. And giving that in some cases the amount of valid data (in bytes) is ? 2 (mod 4) 16-bit access seem to be the obvious thing. Also Sascha only wrote about byte accesses being problematic in 096bcc231fd2. So I'm expecting that 16-bit operators should be fine. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-K?nig | Industrial Linux Solutions | http://www.pengutronix.de/ |