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Date: Wed, 8 Oct 2014 15:33:28 +0300
Message-ID: <CAE1zot+muJn5ngxpq8LeF9J+7kZqCiStzvcxLLP0wf08TjWG4A@mail.gmail.com>
Subject: Re: [PATCH v6 1/4] mfd: add support for Diolan DLN-2 devices
From: Octavian Purdila <octavian.purdila@intel.com>
To: Johan Hovold <johan@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Alexandre Courbot <gnurou@gmail.com>, Wolfram Sang <wsa@the-dreams.de>,
        Samuel Ortiz <sameo@linux.intel.com>, Lee Jones <lee.jones@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>, Daniel Baluta <daniel.baluta@intel.com>,
        Laurentiu Palcu <laurentiu.palcu@intel.com>, linux-usb@vger.kernel.org,
        lkml <linux-kernel@vger.kernel.org>,
        "linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
        linux-i2c@vger.kernel.org
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Sender: linux-kernel-owner@vger.kernel.org

On Wed, Oct 8, 2014 at 3:04 PM, Johan Hovold <johan@kernel.org> wrote:
> On Wed, Oct 08, 2014 at 01:54:07PM +0300, Octavian Purdila wrote:
>> On Wed, Oct 8, 2014 at 12:23 PM, Johan Hovold <johan@kernel.org> wrote:
>> > On Thu, Sep 25, 2014 at 07:07:31PM +0300, Octavian Purdila wrote:
>> >
>> >> +static void dln2_rx_transfer(struct dln2_dev *dln2, struct urb *urb,
>> >> +                          u16 handle, u16 rx_slot)
>> >> +{
>> >> +     struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
>> >> +     struct dln2_rx_context *rxc;
>> >> +     struct device *dev = &dln2->interface->dev;
>> >> +
>> >> +     spin_lock(&rxs->lock);
>> >
>> > You must use spin_lock_irqsave here as you call it from the completion
>> > handler.
>>
>> Why? AFAICS the completion handler gets called from the HCD irq handler:
>
> The completion handler is currently called with local interrupts
> disabled but that is about to change once all drivers have been updated:
>
>         http://marc.info/?l=linux-usb&m=137353360511003&w=2
>
> In this case you could probably get away with not disabling interrupts
> anyway, but using the irqsave versions would make it obvious.
>

I was not assuming that interrupts are disabled while running the
completion handler. Since that spinlock is not touched by any other
interrupt context code I don't think irqsave is necessary.
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