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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Mon, 15 Jul 2019 23:44:31 +0200
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Subject: Re: [PATCH 8/9] acpi: Use built-in RCU list checking for
 acpi_ioremaps list (v1)
To:     "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
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On Mon, Jul 15, 2019 at 4:43 PM Joel Fernandes (Google)
<joel@joelfernandes.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@joelfernandes.org>

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