Re: 2.6.6-mm5

[hch@infradead.org]

> +disk-barrier-core.patch
> +disk-barrier-core-tweaks.patch
> +disk-barrier-ide.patch
> +disk-barrier-ide-symbol-expoprt.patch
> +disk-barrier-ide-warning-fix.patch
> +disk-barrier-scsi.patch
> 
>  Support for IDE and SCSI barriers
> 
> +disk-barrier-dm.patch
> +disk-barrier-md.patch
> 
>  Via device mapper and raid as well.

Some comments on the API and the SCSI part:

 - issue_flush_fn prototype choice is bad, the request_queue_t argument
   wile always be disk->queue so it's not needed and only causes
   confusion.
 - issue_flush sounds a little strange to me, what about cache_flush
   or sync_cache instead?
 - scsi_drive.issue_flush should take a scsi_device * as first parameter,
   not struct device * - makes life for bother caller and callee easier.
 - should probably add a small helper to get the scsi_driver from the
   gendisk instead of duplicating the code, ala:

static inline struct scsi_driver *scsi_disk_driver(struct gendisk *disk)
{
	return *(struct scsi_driver **) disk->private_data;
}

 - the WCE check should move into sd_sync_cache
 - NULL scsi_disk can't happen for sd_issue_flush, no need to check,
   and thus the disctinction of sd_issue_flush vs sd_sync_cache can
   go and sd_shutdown can simply call the cache flush method.