[syslinux] [syslinux:disklib] disklib: make CHS calculation match core/fs/diskio.c

[H. Peter Anvin]

On 10/13/2010 02:44 PM, Michal Soltys wrote:
> On 10-10-13 23:30, H. Peter Anvin wrote:
>> On 10/13/2010 08:36 AM, syslinux-bot for Michal Soltys wrote:
>>>  Commit-ID:  9c8db7560e2dc83d1191bb2f90b4d4d0ae3d37d6
>>>  Gitweb:     http://syslinux.zytor.com/commit/9c8db7560e2dc83d1191bb2f90b4d4d0ae3d37d6
>>>  Author:     Michal Soltys<soltys at ziu.info>
>>>  AuthorDate: Wed, 13 Oct 2010 10:57:36 +0200
>>>  Committer:  Michal Soltys<soltys at ziu.info>
>>>  CommitDate: Wed, 13 Oct 2010 10:57:36 +0200
>>>
>>>  disklib: make CHS calculation match core/fs/diskio.c
>>>
>>>  Signed-off-by: Michal Soltys<soltys at ziu.info>
>>>
>>
>> I note that this code still:
>>
>> a) duplicates the code between read and write, and
> 
> Oki, I'll shrink it.
> 
>> b) doesn't check for CHS overflow.
>>
> 
> lbacnt set in disk_get_params() is always valid (if function is 
> successful), and it's checked at the very begining of read/write 
> functions (along with other sanity checks).
> 
> CHS check is no longer necessary, as CHS is used only if ebios == 0, and 
> that implies that lbacnt is calculated from valid geometry (cbios == 1) 
> or faked (1/1/1) in which lbacnt == 1.
> 
> I'll update the comments to make it more clear.
> 

Ideally, the code should be merged as closely as possible with
core/fs/diskio.c, with the goal of making the diskio.c the *only* code
in Syslinux 5.

	-hpa