Re: [PROPOSED] ata: Report 16/32bit PIO as best we can

From: Jeff Garzik
Date: Mon Apr 13 2009 - 12:58:21 EST


Alan Cox wrote:
On Mon, 13 Apr 2009 12:32:57 -0400
Jeff Garzik <jeff@xxxxxxxxxx> wrote:

I'm not sure sysfs helps much anyway - you have to open the device file
and keep it open while accessing the sysfs nodes anyway (something huge
numbers of apps hopelessly fail to do so)
FWIW... here is the sysfs work I referred to (in a message sent several days ago in this thread)...

http://lwn.net/Articles/294608/

Which indeed shows the same problems. There is nothing to stop changes in
the rest of the topology from causing me to write to the sysfs at the
wrong moment and reconfigure/misconfigure a different object to the one
intended.

The horse has already left the barn, on that one...

Google's ata transport class is consistent with existing transport class work in the kernel. It is also consistent with recent admonitions in the osdblk thread, regarding the "one piece of data per sysfs file" rule.

Personally I think a netlink-like approach to managing and controlling SAS and ATA would be better, but that's not what gets merged...

Jeff



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