linux-kernel - Re: [PATCH v2] PM / wakeirq: Convert to SRCU

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Date:   Mon, 26 Jun 2017 13:37:11 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-rockchip@...ts.infradead.org,
        Julia Cartwright <julia@...com>,
        LKML <linux-kernel@...r.kernel.org>, linux-gpio@...r.kernel.org,
        John Keeping <john@...anate.com>, linux-pm@...r.kernel.org,
        Doug Anderson <dianders@...omium.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Tony Lindgren <tony@...mide.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>
Subject: Re: [PATCH v2]  PM / wakeirq: Convert to SRCU

On Sun, Jun 25, 2017 at 07:31:13PM +0200, Thomas Gleixner wrote:
> The wakeirq infrastructure uses RCU to protect the list of wakeirqs. That
> breaks the irq bus locking infrastructure, which is allows sleeping
> functions to be called so interrupt controllers behind slow busses,
> e.g. i2c, can be handled.
> 
> The wakeirq functions hold rcu_read_lock and call into irq functions, which
> in case of interrupts using the irq bus locking will trigger a
> might_sleep() splat.
> 
> Convert the wakeirq infrastructure to Sleepable RCU and unbreak it.
> 
> Fixes: 4990d4fe327b ("PM / Wakeirq: Add automated device wake IRQ handling")
> Reported-by: Brian Norris <briannorris@...omium.org>
> Suggested-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---
>  drivers/base/power/wakeup.c |   32 ++++++++++++++++++--------------
>  1 file changed, 18 insertions(+), 14 deletions(-)

This resolves the warnings I've seen, for sure. And I don't seem to have
any new suspend/resume problems, so:

Tested-by: Brian Norris <briannorris@...omium.org>