[RFC] mtd: Fix error code loss in mtdchar_read() function.

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "Miquel Raynal" <miquel.raynal at bootlin.com>
>> Given this a second thought. I don't think a NAND driver is allowed to return
>> less than requests bytes and setting EBADMSG.
>> UBI's IO path has a comment on that:
>> 
>>                 /*
>>                  * The driver should never return -EBADMSG if it failed to read
>>                  * all the requested data. But some buggy drivers might do
>>                  * this, so we change it to -EIO.
>>                  */
>>                 if (read != len && mtd_is_eccerr(err)) {
>>                         ubi_assert(0);
>>                         err = -EIO;
>>                 }
> 
> Interesting. Shall we add this check to the mtd_read() path as well?
> 
> Maybe with a WARN_ON()?

WARN_ON_ONCE(), please. But yes, let's add it.

Thanks,
//richard