From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Cameron Subject: Re: [PATCH 2/2] iio: ti_am335x_adc: Add continuous sampling support Date: Thu, 19 Sep 2013 06:33:37 +0100 Message-ID: <39ea39e8-2d11-4c84-ac49-33fdcfa870ed@email.android.com> References: <1379393047-11772-1-git-send-email-zubair.lutfullah@gmail.com> <1379393047-11772-3-git-send-email-zubair.lutfullah@gmail.com> <20130918042726.GB13196@core.coreip.homeip.net> <20130918065406.GA13451@gmail.com> <53771776-0d33-436d-9687-995ed0d6345d@email.android.com> <20130918141533.GA16424@core.coreip.homeip.net> <20130918162442.GA14803@core.coreip.homeip.net> <20130919051611.GA4363@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20130919051611.GA4363-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Zubair Lutfullah :" Cc: Dmitry Torokhov , linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-input-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org List-Id: linux-input@vger.kernel.org "Zubair Lutfullah :" wrote: >On Wed, Sep 18, 2013 at 06:05:12PM +0100, Jonathan Cameron wrote: >> >> >> >However in this case such conversion us dangerous. With all but >IRQ >> >> >resource managed by the traditional methods they will be released >> >first >> >> >with IRQ handler deregistered very last. Therefore if device is >not >> >> >properly quiesced IRQ raised during driver unbinding is likely to >> >> >result >> >> >in kernel oops. >> >> > >> >> >IOW devm_request_irq() is very often evil (it is still useful if >> >_all_ >> >> >your resources are managed by devm_*). >> >> > >> >> >In case of your driver I'd recommend switching to >> >> >request_irq()/free_irq() instead. >> >> > >> >> >Thanks. >> >> >> >> Pretty much all resources are devm managed in here >> >> >> >> >> >>https://git.kernel.org/cgit/linux/kernel/git/jic23/iio.git/tree/drivers/iio/adc/ti_am335x_adc.c?h=togreg&id=7a1aeba7ed0d5a1e83fd5a8ee2a2869430d40347 >> > >> > >> >So we are guaranteed that that new kfifo that is being allocated >just >> >before we requesting IRQ and will be freed way before we free the >IRQ >> >will not be used by the IOTQ handler? >> > >> >Thanks. >> Good point. I forgot about that. The source of interrupts 'should' >be disabled before the kfifo is freed but I guess perhaps better to >play it safe. Would take a fair bit of review to be sure that is not >going to cause grief. >> >> A few more devm handlers need writing before it is truly useful here. >> >> Thanks for pointing this out. >> >> J > >If I understand the conclusion correctly, no devm here? No devm for the irq. The rest are fine. > >Zubair >-- >To unsubscribe from this list: send the line "unsubscribe linux-iio" in >the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >More majordomo info at http://vger.kernel.org/majordomo-info.html -- Sent from my Android phone with K-9 Mail. Please excuse my brevity.