Re: [PATCH] Fix accesses at LBA28 boundary (old bug, but nasty) (v2)

[Jeff Garzik <jgarzik@pobox.com>]

On 04/07/2010 01:52 PM, Mark Lord wrote:
> Most drives from Seagate, Hitachi, and possibly other brands,
> do not allow LBA28 access to sector number 0x0fffffff (2^28 - 1).
> So instead use LBA48 for such accesses.
>
> This bug could bite a lot of systems, especially when the user has
> taken care to align partitions to 4KB boundaries. On misaligned systems,
> it is less likely to be encountered, since a 4KB read would end at
> 0x10000000 rather than at 0x0fffffff.
>
> Signed-off-by: Mark Lord <mlord@pobox.com>
> ---
>
> Reposting with the pre-existing (u64) cast removed.
>
> --- linux-2.6.34-rc3/include/linux/ata.h 2010-03-30 12:24:39.000000000
> -0400
> +++ linux/include/linux/ata.h 2010-04-06 18:39:41.167702612 -0400
> @@ -1025,8 +1025,8 @@
>
> static inline int lba_28_ok(u64 block, u32 n_block)
> {
> - /* check the ending block number */
> - return ((block + n_block) < ((u64)1 << 28)) && (n_block <= 256);
> + /* check the ending block number: must be LESS THAN 0x0fffffff */
> + return ((block + n_block) < ((1 << 28) - 1)) && (n_block <= 256);
> }

applied.

Neither 'git am' nor patch(1) would apply the patch for some reason, so 
I applied it manually.  Weird...  I could not spot obvious whitespace or 
word-wrap corruption.