From: Balbir Singh <bsingharora@gmail.com>
To: Cyril Bur <cyrilbur@gmail.com>,
linuxppc-dev@lists.ozlabs.org, linux-mtd@lists.infradead.org
Cc: stewart@linux.vnet.ibm.com, alistair@popple.id.au,
dwmw2@infradead.org, rlippert@google.com
Subject: Re: [PATCH v3 02/10] mtd: powernv_flash: Lock around concurrent access to OPAL
Date: Mon, 17 Jul 2017 19:29:14 +1000 [thread overview]
Message-ID: <1500283754.8256.11.camel@gmail.com> (raw)
In-Reply-To: <1500278150.29477.1.camel@gmail.com>
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 <cyrilbur@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.
Balbir Singh.
next prev parent reply other threads:[~2017-07-17 9:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-12 4:22 [PATCH v3 00/10] Allow opal-async waiters to get interrupted Cyril Bur
2017-07-12 4:22 ` [PATCH v3 01/10] mtd: powernv_flash: Use WARN_ON_ONCE() rather than BUG_ON() Cyril Bur
2017-07-17 6:19 ` Balbir Singh
2017-07-17 11:33 ` Frans Klaver
2017-07-18 0:27 ` Cyril Bur
2017-07-12 4:22 ` [PATCH v3 02/10] mtd: powernv_flash: Lock around concurrent access to OPAL Cyril Bur
2017-07-17 7:34 ` Balbir Singh
2017-07-17 7:55 ` Cyril Bur
2017-07-17 9:29 ` Balbir Singh [this message]
2017-07-18 1:14 ` Cyril Bur
2017-07-18 3:12 ` Michael Ellerman
2017-07-12 4:22 ` [PATCH v3 03/10] mtd: powernv_flash: Don't treat OPAL_SUCCESS as an error Cyril Bur
2017-07-17 8:50 ` Balbir Singh
2017-07-18 0:42 ` Cyril Bur
2017-07-12 4:22 ` [PATCH v3 04/10] mtd: powernv_flash: Remove pointless goto in driver init Cyril Bur
2017-07-12 4:22 ` [PATCH v3 05/10] powerpc/opal: Make __opal_async_{get, release}_token() static Cyril Bur
2017-07-12 4:23 ` [PATCH v3 06/10] powerpc/opal: Rework the opal-async interface Cyril Bur
2017-07-17 11:30 ` Balbir Singh
2017-07-18 0:40 ` Cyril Bur
2017-07-18 3:20 ` Michael Ellerman
2017-07-12 4:23 ` [PATCH v3 07/10] powernv/opal-sensor: remove not needed lock Cyril Bur
2017-07-12 4:23 ` [PATCH v3 08/10] powerpc/opal: Add opal_async_wait_response_interruptible() to opal-async Cyril Bur
2017-07-12 4:23 ` [PATCH v3 09/10] powerpc/powernv: Add OPAL_BUSY to opal_error_code() Cyril Bur
2017-07-12 4:23 ` [PATCH v3 10/10] mtd: powernv_flash: Use opal_async_wait_response_interruptible() Cyril Bur
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