Re: [PATCH v3 4/4] mtdchar: add MEMREAD ioctl

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "Miquel Raynal" <miquel.raynal@xxxxxxxxxxx>
>> If mtd->erasesize is large (which is not uncommon these days) you might
>> request more from kmalloc() than it can serve.
>> Maybe kvmalloc() makes more sense?
> 
> Mmmh, I would really like these buffers dma-able.
> 
> I just discovered mtd_kmalloc_up_to(). Would this work?

mtd_kmalloc_up_to() makes sense to be more friendly to the system.
It tries to get memory without forcing write-back and such.
But if we're out of continuous memory it won't help much. 

Regarding dma-able, as soon you use something like UBI/UBIFS ontop of it
the mtd driver has to be able to deal in any way with vmalloc()'ed memory.

Another option would be not working on full erase blocks.

Thanks,
//richard