Re: [RFC 4/8] scsi-ml: scsi_sgtable implementation

[Mike Christie <michaelc@cs.wisc.edu>]

Boaz Harrosh wrote:
> +/*
> + * Should fit within a single page.
> + */
> +enum { SCSI_MAX_SG_SEGMENTS =
> +	((PAGE_SIZE - sizeof(struct scsi_sgtable)) /
> +	sizeof(struct scatterlist)) };
> +
> +enum { SG_MEMPOOL_NR =
> +	(SCSI_MAX_SG_SEGMENTS >= 7) +
> +	(SCSI_MAX_SG_SEGMENTS >= 15) +
> +	(SCSI_MAX_SG_SEGMENTS >= 31) +
> +	(SCSI_MAX_SG_SEGMENTS >= 63) +
> +	(SCSI_MAX_SG_SEGMENTS >= 127) +
> +	(SCSI_MAX_SG_SEGMENTS >= 255) +
> +	(SCSI_MAX_SG_SEGMENTS >= 511)
> +};
>  

What does SCSI_MAX_SG_SEGMENTS end up being on x86 now? On x86_64 or 
some other arch, we were going over a page when doing 
SCSI_MAX_PHYS_SEGMENTS of 256 right?

What happened to Jens's scatter list chaining and how does this relate 
to it then?