[Qemu-devel] Re: [PATCH] block.h: Make BDRV_SECTOR_SIZE 64 bit safe

[Jes Sorensen]

On 05/28/10 10:32, Paolo Bonzini wrote:
> On 05/27/2010 05:44 PM, Jes Sorensen wrote:
>> >  Candidate for stable too?
>> It should be safe to apply, but I didn't find any current users where
>> the mask was applied in a way where it was causing problems. Not sure if
>> you want the noise, or apply it as better safe than sorry?
> 
> The only use in fact is this:
> 
>         addr = qemu_get_be64(f);
>         flags = addr & ~BDRV_SECTOR_MASK;
> 
> which is safe since the ~~ cancels to give back 511 again.  So
> nevermind, just asking.  If there are no bugs related to it it seems
> just as safe not to apply it.

That is correct, which is why I don't think it is necessary for the
stable release. However I want to see the fix in upstream as the macro
is likely to get used for other things in the future and it's a hidden
bug waiting to happen.

Cheers,
Jes