| Message ID | 20180718203302.5666-1-miquel.raynal@bootlin.com |
|---|---|
| State | Accepted |
| Delegated to: | Boris Brezillon |
| Headers | show |
| Series | [v2] mtd: adapt misleading comment in mtd_oob_ops structure | expand |
On Wed, 18 Jul 2018 22:33:02 +0200 Miquel Raynal <miquel.raynal@bootlin.com> 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 is actually > true for only a few MTD devices like 'onenand' but it is definitely not > a general limitation. While this would benefit to be handled elsewhere > either by the MTD layer or by the limited drivers, let's update this > comment to reflect the reality. > > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Applied. Thanks, Boris > --- > > Changes since v1: > ================= > * Boris pointed out that this comment was not entirely false but rather > too much restrictive compared to the reality and proposed an > alternative that I simply copied there. > > > include/linux/mtd/mtd.h | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h > index a86c4fa93115..cd0be91bdefa 100644 > --- a/include/linux/mtd/mtd.h > +++ b/include/linux/mtd/mtd.h > @@ -67,9 +67,11 @@ struct mtd_erase_region_info { > * @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. > + * 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;
================= * Boris pointed out that this comment was not entirely false but rather too much restrictive compared to the reality and proposed an alternative that I simply copied there. include/linux/mtd/mtd.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index a86c4fa93115..cd0be91bdefa 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -67,9 +67,11 @@ struct mtd_erase_region_info { * @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. + * 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;
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 is actually true for only a few MTD devices like 'onenand' but it is definitely not a general limitation. While this would benefit to be handled elsewhere either by the MTD layer or by the limited drivers, let's update this comment to reflect the reality. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> --- Changes since v1: