linux-kernel - Re: [PATCH 8/9] acpi: Use built-in RCU list checking for acpi

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Message-ID: <CAJZ5v0jdx1dgBZLyH_Loj1XVuLCV+HMHjk8r_n8xG7qmoH_z3A@mail.gmail.com>
Date:   Mon, 15 Jul 2019 23:44:31 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     "Joel Fernandes (Google)" <joel@...lfernandes.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Borislav Petkov <bp@...en8.de>, c0d1n61at3@...il.com,
        "David S. Miller" <davem@...emloft.net>, edumazet@...gle.com,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
        Jonathan Corbet <corbet@....net>,
        Josh Triplett <josh@...htriplett.org>,
        Kees Cook <keescook@...omium.org>,
        Kernel Hardening <kernel-hardening@...ts.openwall.com>,
        "Cc: Android Kernel" <kernel-team@...roid.com>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Len Brown <lenb@...nel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        Linux PCI <linux-pci@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        NeilBrown <neilb@...e.com>, netdev <netdev@...r.kernel.org>,
        Oleg Nesterov <oleg@...hat.com>,
        "Paul E. McKenney" <paulmck@...ux.ibm.com>,
        Pavel Machek <pavel@....cz>,
        Peter Zijlstra <peterz@...radead.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Rasmus Villemoes <rasmus.villemoes@...vas.dk>,
        rcu@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
        Tejun Heo <tj@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Will Deacon <will@...nel.org>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>
Subject: Re: [PATCH 8/9] acpi: Use built-in RCU list checking for
 acpi_ioremaps list (v1)

On Mon, Jul 15, 2019 at 4:43 PM Joel Fernandes (Google)
<joel@...lfernandes.org> wrote:
>
> list_for_each_entry_rcu has built-in RCU and lock checking. Make use of
> it for acpi_ioremaps list traversal.
>
> Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

> ---
>  drivers/acpi/osl.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index 9c0edf2fc0dd..2f9d0d20b836 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -14,6 +14,7 @@
>  #include <linux/slab.h>
>  #include <linux/mm.h>
>  #include <linux/highmem.h>
> +#include <linux/lockdep.h>
>  #include <linux/pci.h>
>  #include <linux/interrupt.h>
>  #include <linux/kmod.h>
> @@ -80,6 +81,7 @@ struct acpi_ioremap {
>
>  static LIST_HEAD(acpi_ioremaps);
>  static DEFINE_MUTEX(acpi_ioremap_lock);
> +#define acpi_ioremap_lock_held() lock_is_held(&acpi_ioremap_lock.dep_map)
>
>  static void __init acpi_request_region (struct acpi_generic_address *gas,
>         unsigned int length, char *desc)
> @@ -206,7 +208,7 @@ acpi_map_lookup(acpi_physical_address phys, acpi_size size)
>  {
>         struct acpi_ioremap *map;
>
> -       list_for_each_entry_rcu(map, &acpi_ioremaps, list)
> +       list_for_each_entry_rcu(map, &acpi_ioremaps, list, acpi_ioremap_lock_held())
>                 if (map->phys <= phys &&
>                     phys + size <= map->phys + map->size)
>                         return map;
> @@ -249,7 +251,7 @@ acpi_map_lookup_virt(void __iomem *virt, acpi_size size)
>  {
>         struct acpi_ioremap *map;
>
> -       list_for_each_entry_rcu(map, &acpi_ioremaps, list)
> +       list_for_each_entry_rcu(map, &acpi_ioremaps, list, acpi_ioremap_lock_held())
>                 if (map->virt <= virt &&
>                     virt + size <= map->virt + map->size)
>                         return map;
> --
> 2.22.0.510.g264f2c817a-goog
>