Re: [PATCH 4/4] mvsas: Fine-tuned tags array for alignment

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Sat, 2009-05-09 at 02:52 -0400, Jeff Garzik wrote:
> Ying Chu wrote:
> > Hi, James
> > 
> > DECLARE_BITMAP isn't a good option for mvsas, since the tags array couldn't be global(it's chip-related) and even if we define the static tag array both in mv64xx.c and mv94xx.c, it still couldn't honor 88SE9480 as there are 2 separate cores. So if we use DECLARE_BITMAP, it's hard to maintain the corresponding tag for different core.  
> > 
> > Can we use the following replacement:
> >  -	u8 tags[MVS_SLOTS >> 3];
> >  +	unsigned long tags[MVS_SLOTS / BITS_PER_LONG];
> 
> You are doing exactly the same thing as DECLARE_BITMAP here, so just use 
> DECLARE_BITMAP :)
> 
> include/linux/types.h:
> 	#define DECLARE_BITMAP(name,bits) \
> 	        unsigned long name[BITS_TO_LONGS(bits)]

Right, it's one of those annoying definitions that's designed to be
compound, so things like

static DECLARE_BITMAP(x, y);

is legal as well as

struct {
	DECLARE_BITMAP(x,y);
};

in either case, the scope is precisely what an ordinary variable would
have had at that point.

Most of our DECLARE_XX are designed like this.

James