On Thu, 8 Jun 2006, James Bottomley wrote: > On Tue, 2006-06-06 at 11:31 -0400, Alan Stern wrote: > > This patch (as695) changes the scsi_test_unit_ready() routine in the > > SCSI > > core to set a new flag when no medium is present. The sd driver is > > changed to use this new flag for reporting -ENOMEDIUM in from the > > sd_media_changed method. > > This would appear to be duplicating the struct scsi_disk media_present > flag. Correct, although the semantics of the two flags aren't exactly the same. > Moving the media_present flag from scsi_disk to scsi_device may > make a bit of sense long term ... however, there's also dupication with > the sr driver and the cdrom layer now (that stores media change at the > cdrom level), so is there an argument why it's better in scsi_device > than scsi_disk? I did it that way in the patch because it was the only simple choice. The scsi_test_unit_ready() routine is part of the SCSI core and can be called for devices that aren't disks. Hence any flag it sets cannot be part of the scsi_disk structure. In principle the information could be conveyed in the return value from scsi_test_unit_ready() rather than in a static flag. But the routine has several callers and I didn't want to change all of them to recognize a -ENOMEDIUM return code. Now in the long run, perhaps that would be a good thing to do. Or perhaps moving the flag to scsi_device would be better, I don't know... Ultimately this boils down to how you want to represent "No medium present" in the SCSI core. What do you think is the bets way? Alan Stern - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
