Re: Size of sector_t in userspace [Was: fix 41 'make headers_check' warnings]

[Jens Axboe]

On Wed, Jan 21 2009, Sam Ravnborg wrote:
> Hi Jens.
> 
> In an attempt to fix some of the issues in our exported Headers jsr
> encountered some strange stuff in types.h.
> 
> types.h is exported to userspace where we do not have access to CONFIG_*
> symbols.
> Despite this we use CONFGI_LBD to decide the size of sector_t like this:
> 
> #ifdef CONFIG_LBD
> typedef u64 sector_t;
> typedef u64 blkcnt_t;
> #else
> typedef unsigned long sector_t;
> typedef unsigned long blkcnt_t;
> #endif
> 
> But as CONFIG_LBD is never defined in userspace sector_t is now 32
> bit on 32 bit boxes and 64 bit on 64 bit boxes (in userspace).
> 
> Is sector:t (and the companion blkcnt_t) really used by userspace?
> If it is - what size is it expected to have?

I don't think it's used by userspace, at least it cannot be used in
userspace <-> kernelspace interactions, since the size isn't fixed.

-- 
Jens Axboe

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/