2005-03-09 16:09:34

by Bagalkote, Sreenivas

Subject: RE: [ANNOUNCE][PATCH 2.6.11 2/3] megaraid_sas: Announcing new mod ule for LSI Logic's SAS based MegaRAID controllers

>
>> . And since this is compile time
>> system-wide property, I kept it as driver global.
>
>that step I don't understand... why is it a global *VARIABLE* if it's
>compile time system-wide property...
>

I see your point! Are you saying I should use if(sizeof(dma_addr_t)==8)
instead of the shortcut if(is_dma64)? Are you thinking of "const" modifier?
Please advice.

2005-03-09 17:16:47

by Arjan van de Ven

Subject: RE: [ANNOUNCE][PATCH 2.6.11 2/3] megaraid_sas: Announcing new mod ule for LSI Logic's SAS based MegaRAID controllers

On Wed, 2005-03-09 at 11:01 -0500, Bagalkote, Sreenivas wrote:
> >
> >> . And since this is compile time
> >> system-wide property, I kept it as driver global.
> >
> >that step I don't understand... why is it a global *VARIABLE* if it's
> >compile time system-wide property...
> >
>
> I see your point! Are you saying I should use if(sizeof(dma_addr_t)==8)
> instead of the shortcut if(is_dma64)?
yep
well you can use a preprocessor define of something to make it slightly
more readable (eg shortcut) if you want, but that's what I mean yeah..

gcc will optimize the entire unused code away this way, including the
actual conditional jump, so for performance and bloat-ness point of view
it's nice.... and of course generic design beauty ;)