[v2,03/28] acpi: utils: Cleanup acpi_dev_match_cb
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Message ID 1560534863-15115-4-git-send-email-suzuki.poulose@arm.com
State New
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Series
  • [v2,01/28] staging: most-core: Use bus_find_device_by_name
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Commit Message

Suzuki K Poulose June 14, 2019, 5:53 p.m. UTC
The prototype of bus_find_device() will be unified with that of
class_find_device() subsequently, but for this purpose the callback
functions passed to it need to take (const void *) as the second
argument.  Consequently, they cannot modify the memory pointed to by
that argument which currently is not the case for acpi_dev_match_cb().
However, acpi_dev_match_cb() really need not modify the "match" object
passed to it, because acpi_dev_get_first_match_dev() which uses it via
bus_find_device() can easily convert the result of bus_find_device()
into the pointer to return.

For this reason, update acpi_dev_match_cb() to avoid the redundant
memory updates.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/acpi/utils.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

Comments

Rafael J. Wysocki June 17, 2019, 10:08 p.m. UTC | #1
On Fri, Jun 14, 2019 at 7:54 PM Suzuki K Poulose <suzuki.poulose@arm.com> wrote:
>
> The prototype of bus_find_device() will be unified with that of
> class_find_device() subsequently, but for this purpose the callback
> functions passed to it need to take (const void *) as the second
> argument.  Consequently, they cannot modify the memory pointed to by
> that argument which currently is not the case for acpi_dev_match_cb().
> However, acpi_dev_match_cb() really need not modify the "match" object
> passed to it, because acpi_dev_get_first_match_dev() which uses it via
> bus_find_device() can easily convert the result of bus_find_device()
> into the pointer to return.
>
> For this reason, update acpi_dev_match_cb() to avoid the redundant
> memory updates.
>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Len Brown <lenb@kernel.org>
> Cc: linux-acpi@vger.kernel.org
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

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

Or if you want me to take this patch, please let me know.

> ---
>  drivers/acpi/utils.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
> index 7def63a..1391b63 100644
> --- a/drivers/acpi/utils.c
> +++ b/drivers/acpi/utils.c
> @@ -725,8 +725,6 @@ bool acpi_dev_found(const char *hid)
>  EXPORT_SYMBOL(acpi_dev_found);
>
>  struct acpi_dev_match_info {
> -       const char *dev_name;
> -       struct acpi_device *adev;
>         struct acpi_device_id hid[2];
>         const char *uid;
>         s64 hrv;
> @@ -746,9 +744,6 @@ static int acpi_dev_match_cb(struct device *dev, void *data)
>             strcmp(adev->pnp.unique_id, match->uid)))
>                 return 0;
>
> -       match->dev_name = acpi_dev_name(adev);
> -       match->adev = adev;
> -
>         if (match->hrv == -1)
>                 return 1;
>
> @@ -818,7 +813,7 @@ acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
>         match.hrv = hrv;
>
>         dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
> -       return dev ? match.adev : NULL;
> +       return dev ? to_acpi_device(dev) : NULL;
>  }
>  EXPORT_SYMBOL(acpi_dev_get_first_match_dev);
>
> --
> 2.7.4
>
Greg KH June 24, 2019, 3:20 a.m. UTC | #2
On Tue, Jun 18, 2019 at 12:08:45AM +0200, Rafael J. Wysocki wrote:
> On Fri, Jun 14, 2019 at 7:54 PM Suzuki K Poulose <suzuki.poulose@arm.com> wrote:
> >
> > The prototype of bus_find_device() will be unified with that of
> > class_find_device() subsequently, but for this purpose the callback
> > functions passed to it need to take (const void *) as the second
> > argument.  Consequently, they cannot modify the memory pointed to by
> > that argument which currently is not the case for acpi_dev_match_cb().
> > However, acpi_dev_match_cb() really need not modify the "match" object
> > passed to it, because acpi_dev_get_first_match_dev() which uses it via
> > bus_find_device() can easily convert the result of bus_find_device()
> > into the pointer to return.
> >
> > For this reason, update acpi_dev_match_cb() to avoid the redundant
> > memory updates.
> >
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> > Cc: Len Brown <lenb@kernel.org>
> > Cc: linux-acpi@vger.kernel.org
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> 
> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Or if you want me to take this patch, please let me know.

I'll take it now, thanks.

greg k-h

Patch
diff mbox series

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 7def63a..1391b63 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -725,8 +725,6 @@  bool acpi_dev_found(const char *hid)
 EXPORT_SYMBOL(acpi_dev_found);
 
 struct acpi_dev_match_info {
-	const char *dev_name;
-	struct acpi_device *adev;
 	struct acpi_device_id hid[2];
 	const char *uid;
 	s64 hrv;
@@ -746,9 +744,6 @@  static int acpi_dev_match_cb(struct device *dev, void *data)
 	    strcmp(adev->pnp.unique_id, match->uid)))
 		return 0;
 
-	match->dev_name = acpi_dev_name(adev);
-	match->adev = adev;
-
 	if (match->hrv == -1)
 		return 1;
 
@@ -818,7 +813,7 @@  acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv)
 	match.hrv = hrv;
 
 	dev = bus_find_device(&acpi_bus_type, NULL, &match, acpi_dev_match_cb);
-	return dev ? match.adev : NULL;
+	return dev ? to_acpi_device(dev) : NULL;
 }
 EXPORT_SYMBOL(acpi_dev_get_first_match_dev);