Re: [PATCHv2 4/5] libmtd: add support for 64-bit offsets, OOB

[Artem Bityutskiy <dedekind1@gmail.com>]

On Wed, 2010-07-07 at 17:30 -0700, Kevin Cernekee wrote:
> Change mtd_erase() so that it attempts to use MEMERASE64 first, then falls
> back to the old <2.6.31 MEMERASE if MEMERASE64 is unsupported.
> 
> Add mtd_read_oob(), mtd_write_oob() functions to wrap the OOB ioctls.
> Similar ioctl fallback logic is used in these functions as well.
> 
> Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
> ---
>  include/libmtd.h |   36 ++++++++++++++++++++++-
>  lib/libmtd.c     |   82 ++++++++++++++++++++++++++++++++++++++++++++++++++---
>  2 files changed, 111 insertions(+), 7 deletions(-)
> 
> diff --git a/include/libmtd.h b/include/libmtd.h
> index 0aea966..292d8c3 100644
> --- a/include/libmtd.h
> +++ b/include/libmtd.h
> @@ -66,6 +66,7 @@ struct mtd_info
>   * @region_cnt: count of additional erase regions
>   * @writable: zero if the device is read-only
>   * @bb_allowed: non-zero if the MTD device may have bad eraseblocks
> + * @legacy_ioctls: non-zero if the kernel lacks MEMERASE64, MEM*OOB64
>   */
>  struct mtd_dev_info
>  {
> @@ -84,6 +85,7 @@ struct mtd_dev_info
>  	int region_cnt;
>  	unsigned int writable:1;
>  	unsigned int bb_allowed:1;
> +	unsigned int legacy_ioctls:1;
>  };

Kevin, I'm sorry, but thinking about this some more, this is not a
property of mtd device, this is a property of whole mtd subsystem. So
this flag should live in 'struct mtd_info', just like the 'unsigned int
sysfs_supported:1;' field.

You should find out whether the new ioctl's are supported in
'libmtd_open()'. This also means that all libmtd calls which need this
flag will need a 'libmtd_t desc' parameter.

Also, is it possible to have 2 separate patches - 1st adds support for
64-bit offest, second adds OOB calls.

Is this doable? I think this should not be too difficult to change.

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)