Re: lots and lots of disks again

[Christoph Hellwig <hch@infradead.org>]

On Tue, Feb 10, 2004 at 12:26:58PM +0100, Kurt Garloff wrote:
> +/* sd_index_bits array size / disks
> + * 			32  /    256
> + * 		      4096  /  32768
> + * 		     32768  / 262144
> + */
> +#ifdef CONFIG_EMBEDDED
> +# define SD_DISKS	256
> +#else
> +# define SD_DISKS	32768	// we can raise this to 262144 if needed
> +#endif

Umm, using CONFIG_EMBEDDED doesn't mean no config option - it just mean
another config option which no-one would think of changing the number of
support scsi disks.

Really, any solution that requires huge static allocations is wrong.  The
bitmap either needs to be replaced with a saner algorithm or dynamic
allocation and reallocation on growth.

>  }
>  
> +static int inv_sd_major(int major)
> +{
> +	switch (major) {
> +	case SCSI_DISK0_MAJOR:
> +		return 0;
> +	case SCSI_DISK1_MAJOR ... SCSI_DISK7_MAJOR:
> +		return major + 1 - SCSI_DISK1_MAJOR;
> +	case SCSI_DISK8_MAJOR ... SCSI_DISK15_MAJOR:
> +		return major + 8 - SCSI_DISK8_MAJOR;
> +	default:
> +		BUG();
> +		return 0;	/* shut up gcc */
> +	}
> +}
> +
> +unsigned int dev_to_sd_nr(unsigned int dev) {
> +	return  ((dev >> 4) & 15) | (inv_sd_major(dev >> 20) << 4) |
> +		(dev & 0x3ff00);
> +}
> +unsigned int dev_to_sd_part(unsigned int dev) {
> +	return  (dev & 15) | ((dev >> 14) & 0x30);
> +}
> +

Maybe I missed something but this seems completely unused?

Also please follow the coding style guidelines, that is opening brace
for functions on the next line and non-exported functions always static.