Subject: Re: [PATCH v3 02/10] mtd: powernv_flash: Lock around concurrent access to OPAL

From: Cyril Bur <[email-masked]>
Date: Mon, 17 Jul 2017 17:55:50 +1000

On Mon, 2017-07-17 at 17:34 +1000, Balbir Singh wrote:
> On Wed, 2017-07-12 at 14:22 +1000, Cyril Bur wrote:
> > OPAL can only manage one flash access at a time and will return an
> > OPAL_BUSY error for each concurrent access to the flash. The simplest
> > way to prevent this from happening is with a mutex.
> > 
> > Signed-off-by: Cyril Bur <[email-masked]>
> > ---
> 
> Should the mutex_lock() be mutex_lock_interruptible()? Are we OK waiting on
> the mutex while other operations with the lock are busy?
> 

This is a good question. My best interpretation is that
_interruptible() should be used when you'll only be coming from a user
context. Which is mostly true for this driver, however, MTD does
provide kernel interfaces, so I was hesitant, there isn't a great deal
of use of _interruptible() in drivers/mtd. 

Thoughts?

Cyril

> Balbir Singh.