On Mon, 2017-07-17 at 19:29 +1000, Balbir Singh wrote: > On Mon, 2017-07-17 at 17:55 +1000, Cyril Bur wrote: > > 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 <cyril...@gmail.com> > > > > --- > > > > > > 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? > > What are the kernel interfaces (I have not read through mtd in detail)? > I would still like to see us not blocked in mutex_lock() across threads > for parallel calls, one option is to use mutex_trylock() and return if > someone already holds the mutex with -EBUSY, but you'll need to evaluate > what that means for every call. >
Yeah maybe mutex_trylock() is the way to go, thinking quickly, I don't see how it could be a problem for userspace using powernv_flash. I'm honestly not too sure about the depths of the mtd kernel interfaces but I've seen a tonne of cool stuff you could do, hence my reluctance to go with _interruptible() Cyril > Balbir Singh. >
