On Thu, Feb 8, 2018 at 5:53 PM, Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> On Thu, 2018-02-08 at 16:59 +0100, Rafael J. Wysocki wrote:
>> On Wed, Feb 7, 2018 at 3:56 PM, Andy Shevchenko
>> <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>> >
>
>> And as far as I'm concerned you can do:
>>
>> if (!strcmp(ACPI_DT_NAMESPACE_HID, hwid->id)
>> return (const struct acpi_device_id
>> *)acpi_of_match_device(device, of_ids);
>>
>> and update the comment accordingly.
>
> Would the following work for you?
Yes, it would.
> --- 8< --- 8< --- 8< ---
> From 03013c0c1e487cda4c0d8dc5065ed2f0031095de Mon Sep 17 00:00:00 2001
> From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Date: Thu, 1 Feb 2018 21:52:14 +0200
> Subject: [PATCH 1/1] ACPI / bus: Do not traverse through non-existed
> device
> table
>
> When __acpi_match_device() is called it would be possible to have
> ACPI ID table a MULL pointer. To avoid potential dereference,
> check for this before traverse.
>
> This patch implies a bit of refactoring acpi_of_match_device() to return
> pointer to OF ID when matched followed by refactoring
> __acpi_match_device() to return either ACPI or OF ID when matches.
>
> While here, remove redundant 'else'.
>
> Cc: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
> Cc: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> Cc: Vinod Koul <vinod.koul@xxxxxxxxx>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> drivers/acpi/bus.c | 66 +++++++++++++++++++++++++++++++++------------
> ---------
> 1 file changed, 41 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> index 676c9788e1c8..33c5166e6028 100644
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -660,13 +660,15 @@ struct acpi_device *acpi_companion_match(const
> struct device *dev)
> * acpi_of_match_device - Match device object using the "compatible"
> property.
> * @adev: ACPI device object to match.
> * @of_match_table: List of device IDs to match against.
> + * @of_id: OF ID if matched
> *
> * If @dev has an ACPI companion which has ACPI_DT_NAMESPACE_HID in its
> list of
> * identifiers and a _DSD object with the "compatible" property, use
> that
> * property to match against the given list of identifiers.
> */
> static bool acpi_of_match_device(struct acpi_device *adev,
> - const struct of_device_id
> *of_match_table)
> + const struct of_device_id
> *of_match_table,
> + const struct of_device_id **of_id)
> {
> const union acpi_object *of_compatible, *obj;
> int i, nval;
> @@ -690,8 +692,11 @@ static bool acpi_of_match_device(struct acpi_device
> *adev,
> const struct of_device_id *id;
>
> for (id = of_match_table; id->compatible[0]; id++)
> - if (!strcasecmp(obj->string.pointer, id-
>>compatible))
> + if (!strcasecmp(obj->string.pointer, id-
>>compatible)) {
> + if (of_id)
> + *of_id = id;
> return true;
> + }
> }
>
> return false;
> @@ -762,10 +767,11 @@ static bool __acpi_match_device_cls(const struct
> acpi_device_id *id,
> return true;
> }
>
> -static const struct acpi_device_id *__acpi_match_device(
> - struct acpi_device *device,
> - const struct acpi_device_id *ids,
> - const struct of_device_id *of_ids)
> +static bool __acpi_match_device(struct acpi_device *device,
> + const struct acpi_device_id *acpi_ids,
> + const struct of_device_id *of_ids,
> + const struct acpi_device_id **acpi_id,
> + const struct of_device_id **of_id)
> {
> const struct acpi_device_id *id;
> struct acpi_hardware_id *hwid;
> @@ -775,30 +781,35 @@ static const struct acpi_device_id
> *__acpi_match_device(
> * driver for it.
> */
> if (!device || !device->status.present)
> - return NULL;
> + return false;
>
> list_for_each_entry(hwid, &device->pnp.ids, list) {
> /* First, check the ACPI/PNP IDs provided by the
> caller. */
> - for (id = ids; id->id[0] || id->cls; id++) {
> - if (id->id[0] && !strcmp((char *) id->id, hwid-
>>id))
> - return id;
> - else if (id->cls && __acpi_match_device_cls(id,
> hwid))
> - return id;
> + if (acpi_ids) {
> + bool found;
> +
> + for (id = acpi_ids; id->id[0] || id->cls; id++)
> {
> + found = false;
> + if (id->id[0] && !strcmp((char *)id-
>>id, hwid->id))
> + found = true;
> + if (id->cls &&
> __acpi_match_device_cls(id, hwid))
> + found = true;
> + if (found) {
> + if (acpi_id)
> + *acpi_id = id;
> + return true;
> + }
> + }
> }
>
> /*
> * Next, check ACPI_DT_NAMESPACE_HID and try to match
> the
> * "compatible" property if found.
> - *
> - * The id returned by the below is not valid, but the
> only
> - * caller passing non-NULL of_ids here is only
> interested in
> - * whether or not the return value is NULL.
> */
> - if (!strcmp(ACPI_DT_NAMESPACE_HID, hwid->id)
> - && acpi_of_match_device(device, of_ids))
> - return id;
> + if (!strcmp(ACPI_DT_NAMESPACE_HID, hwid->id))
> + return acpi_of_match_device(device, of_ids,
> of_id);
> }
> - return NULL;
> + return false;
> }
>
> /**
> @@ -815,7 +826,10 @@ static const struct acpi_device_id
> *__acpi_match_device(
> const struct acpi_device_id *acpi_match_device(const struct
> acpi_device_id *ids,
> const struct device
> *dev)
> {
> - return __acpi_match_device(acpi_companion_match(dev), ids,
> NULL);
> + const struct acpi_device_id *id = NULL;
> +
> + __acpi_match_device(acpi_companion_match(dev), ids, NULL, &id,
> NULL);
> + return id;
> }
> EXPORT_SYMBOL_GPL(acpi_match_device);
>
> @@ -840,7 +854,7 @@ EXPORT_SYMBOL_GPL(acpi_get_match_data);
> int acpi_match_device_ids(struct acpi_device *device,
> const struct acpi_device_id *ids)
> {
> - return __acpi_match_device(device, ids, NULL) ? 0 : -ENOENT;
> + return __acpi_match_device(device, ids, NULL, NULL, NULL) ? 0 :
> -ENOENT;
> }
> EXPORT_SYMBOL(acpi_match_device_ids);
>
> @@ -849,10 +863,12 @@ bool acpi_driver_match_device(struct device *dev,
> {
> if (!drv->acpi_match_table)
> return acpi_of_match_device(ACPI_COMPANION(dev),
> - drv->of_match_table);
> + drv->of_match_table,
> + NULL);
>
> - return !!__acpi_match_device(acpi_companion_match(dev),
> - drv->acpi_match_table, drv-
>>of_match_table);
> + return __acpi_match_device(acpi_companion_match(dev),
> + drv->acpi_match_table, drv-
>>of_match_table,
> + NULL, NULL);
> }
> EXPORT_SYMBOL_GPL(acpi_driver_match_device);
>
> --
> 2.15.1
>
>
>
> --
> Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Intel Finland Oy
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