2007-08-10 20:39:14

by Alasdair G Kergon

[permalink] [raw]
Subject: Re: [patch 05/11] dm-snap: remove SECTOR_SHIFT define

On Fri, Aug 10, 2007 at 10:02:09PM +0200, Jan Blunck wrote:
> Sector size on Linux is always 512 bytes. Don't even try to give the
> impression this is changeable.

If that's what worries you, add a comment next to the definition,
perhaps?

It's there so you can easily locate all the places within dm that
perform these conversions by using a simple search. Searching for '9'
wouldn't be as easy. (I don't know about other people, but I find the
code easier to read the way it is.)

BTW When changing one thing across the whole of dm, you may combine
the sub-component patches into a single patch.

Alasdair
--
[email protected]


2007-08-13 13:25:11

by Jan Blunck

[permalink] [raw]
Subject: Re: [patch 05/11] dm-snap: remove SECTOR_SHIFT define

On Fri, Aug 10, Alasdair G Kergon wrote:

> On Fri, Aug 10, 2007 at 10:02:09PM +0200, Jan Blunck wrote:
> > Sector size on Linux is always 512 bytes. Don't even try to give the
> > impression this is changeable.
>
> If that's what worries you, add a comment next to the definition,
> perhaps?

That and that the code just looks more like the rest of the block layer
code. Only a few users (UFS, MSDOS, HFS, IDE) use a predefined
SECTOR_{SHIFT,SIZE}.

> It's there so you can easily locate all the places within dm that
> perform these conversions by using a simple search. Searching for '9'
> wouldn't be as easy. (I don't know about other people, but I find the
> code easier to read the way it is.)

Hmm, so I guess this is more about dis/like of how the code looks. Maybe we
should define a global SECTOR_{SIZE,SHIFT} into blkdev.h.

Regards,
Jan

--
Jan Blunck <[email protected]>