Re: [PATCH]usblp read race

Am Dienstag, 15. Mai 2007 06:14 schrieb Pete Zaitcev:
> On Tue, 15 May 2007 05:10:36 +0200, Oliver Neukum <[email protected]> wrote:
> 
> > 	rv = usblp_rwait_and_lock(usblp, !!(file->f_flags & O_NONBLOCK));
> > 	if (rv < 0) {
> > 		count = rv;
> > 		goto done;
> > 	}
> > 
> > If you get a signal, the mutex will _not_ be locked, yet it'll be unlocked.
> 
> You are quite right, thanks. The oddest thing though, I tested this
> path by running cat </dev/usb/lp0 and ^C, and nothing bad happened.
> Mutex debugging didn't catch it.

They might think that unlocking an unlocked mutex is a nop.
I know nothing about mutex debugging.

> 
> > 2. usblp_write():	
> > 	if ((rv = usb_submit_urb(usblp->writeurb, GFP_KERNEL)) < 0) {
> > 			usblp->wcomplete = 1;
> > 			usblp->wstatus = 0;
> > 			mutex_unlock (&usblp->mut);
> > 			return writecount ? writecount : -EIO;
> > 
> > At least ENOMEM we'd probably like to report as such.
> 
> Actually yes, I did not preserve what the old driver did here, sorry.
> But oddly enough, it only returned ENOMEM for writes, but not reads.
> I changed this to match the legacy.

OK.

	Regards
		Oliver

-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/
_______________________________________________
[email protected]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel