From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.bootlin.com ([62.4.15.54]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ffP34-0002bz-1e for linux-mtd@lists.infradead.org; Tue, 17 Jul 2018 12:25:47 +0000 Date: Tue, 17 Jul 2018 14:25:24 +0200 From: Boris Brezillon To: Miquel Raynal Cc: Richard Weinberger , David Woodhouse , Brian Norris , Marek Vasut , linux-mtd@lists.infradead.org Subject: Re: [PATCH] mtd: remove stale comment in mtd_oob_ops structure Message-ID: <20180717142524.434972e6@bbrezillon> In-Reply-To: <20180714123234.16127-1-miquel.raynal@bootlin.com> References: <20180714123234.16127-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, 14 Jul 2018 14:32:34 +0200 Miquel Raynal wrote: > A comment in the kernel doc of the mtd_oob_ops structure tells that it > is not possible to write more than one page with OOB. This was > probably true at some time in the past but today it is entirely wrong. > > As one can see for instance in the nand_do_write_ops() helper available > in the NAND core, this implementation called by mtd->_write_oob() > simply loops over the pages until everything has been written. > > Signed-off-by: Miquel Raynal > --- > include/linux/mtd/mtd.h | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h > index a86c4fa93115..59578aab277a 100644 > --- a/include/linux/mtd/mtd.h > +++ b/include/linux/mtd/mtd.h > @@ -66,10 +66,6 @@ struct mtd_erase_region_info { > * mode = MTD_OPS_PLACE_OOB or MTD_OPS_RAW) > * @datbuf: data buffer - if NULL only oob data are read/written > * @oobbuf: oob data buffer > - * > - * Note, it is allowed to read more than one OOB area at one go, but not write. > - * The interface assumes that the OOB write requests program only one page's > - * OOB area. Hm, I wouldn't be so prompt at nuking this comment since some implementations (like onenand) really have this limitation. How about adjusting the comment to reflect the fact that this limitation is implementation dependent? " Note, some MTD drivers do not allow you to write more than one OOB area at one go. If you try to do that on such an MTD device, -EINVAL will be returned. If you want to make your implementation portable on all kind of MTD devices you should split the write request into several sub-requests when the request crosses a page boundary. " > */ > struct mtd_oob_ops { > unsigned int mode;