[U-Boot] [PATCH v2 1/4] nand: Extend nand_(read|write)_skip_bad with *actual and limit parameters

[Tom Rini <trini@ti.com>]

On Tue, Feb 26, 2013 at 10:56:08AM -0500, Tom Rini wrote:

> We make these two functions take a size_t pointer to how much space
> was used on NAND to read or write the buffer (when reads/writes happen)
> so that bad blocks can be accounted for.  We also make them take an
> loff_t limit on how much data can be read or written.  This means that
> we can now catch the case of when writing to a partition would exceed
> the partition size due to bad blocks.  To do this we also need to make
[snip]
>  int nand_read_skip_bad(nand_info_t *nand, loff_t offset, size_t *length,
> -		       u_char *buffer)
> +		       size_t *actual, loff_t lim, u_char *buffer)
[snip]
> +	if (*actual > lim) {
> +		puts("Size of read exceeds partition or device limit\n");
> +		*length = 0;
> +		return -EFBIG;
> +	}

The more I look at this and try testing things, I think I shouldn't be
introducing a change here.  Before you could do:
nand read ${address} partname-with-badblock

And it would suceed but bleed into the next partition if it wasn't the
last one.  So your production system could do "nand read ${address}
kernel" and be OK.  But with this change, it would fail because reading
the whole partition is now too large with a bad block (you would need
partition+(blocksize*number bad blocks).

So I'm going to put this back to a check simply against requested size
being greater than lim rather than required size greater than lim (since
required size exceeds device is still caught).

-- 
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 836 bytes
Desc: Digital signature
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20130227/b62f0136/attachment.pgp>