Re: eata irq abuse (was: Re: Linux 2.5.60)

[James Bottomley <James.Bottomley@steeleye.com>]

On Wed, 2003-02-12 at 08:51, Christoph Hellwig wrote:
> On Wed, Feb 12, 2003 at 08:40:34AM -0600, James Bottomley wrote:
> > > Ah, you don't need the lock but the disabled interrupts!
> > 
> > In general, that's not correct: most HBA registers have to be accessed
> > in sequence, thus you need global protection from anyone else touching
> > them while you're at the registers.  This is what host_lock was designed
> > for.
> 
> Of course.  but that's not how driver_lock in eata.c works.  It's taken
> when we enter eata2x_detect(), dropped before scsi_register(), reacquired
> afterwards and released when we leave eata2x_detect().  I don't really
> see what it is supposed to protect.

I agree, I'll look over the driver while I'm travelling today and see if
we can do better.  I just didn't want to give the impression that
local_irq_disable() is sufficient protection when accessing board
registers (having seen one or two SMP problems related to this).

James