Re: [PATCH] Remove arbitrary md= boot device limit

[Neil Brown]

On Monday January 29, [e-mail] wrote:
> linux-2.4.1p11-1/drivers/md/md.c
> line 3643
> -#define MAX_MD_BOOT_DEVS     8
> +#define MAX_MD_BOOT_DEVS     MAX_MD_DEVS
> 
> -------------------------------------------------------
> To:  Dave Cinege <[e-mail]>
> 
> On Mon, 29 Jan 2001, Dave Cinege wrote:
> 
> > -#define MAX_MD_BOOT_DEVS     8
> > +#define MAX_MD_BOOT_DEVS     MAX_MD_DEVS
> 
> sure this is fine.
> 
>         Ingo

Actually, this is not fine.  Check the code that says:

	if (minor >= MAX_MD_BOOT_DEVS) {
		printk ("md: Minor device number too high.\n");
		return 0;
	} else if (md_setup_args.set & (1 << minor)) {
		printk ("md: Warning - md=%d,... has been specified twice;\n"
			"    will discard the first definition.\n", minor);
	}
     ..........
	md_setup_args.set |= (1 << minor);

Note that "md_setup_args.set" is an unsigned long.
If minor >= 32, then we wont successfully set a bit in the set, and
things wont work right.

NeilBrown

> -------------------------------------------------------
> To:	Ingo Molnar <[e-mail]>
> 
> Devices above md8 will not be initialized when speced with md=.
> Error ("md: Minor device number too high.\n");
> 
> The limitation is imposed by
>         #define MAX_MD_BOOT_DEVS        8
> However it appears arbitray to me. Doesn't make much sence since you can create
> /dev/md100 and it may well be the only md device you have...
> 
> Is there any reason the next 2.4.1 prepatch should not include this?
> 
> -#define MAX_MD_BOOT_DEVS       8
> +#define MAX_MD_BOOT_DEVS       MAX_MD_DEVS
> 
> (If not I assume you will be submitting this to Linus...)
> 
> -- 
> "Nobody will ever be safe until the last cop is dead."
> 		NH Rep. Tom Alciere - (My new Hero)
> -
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