Messages in this thread | | | Subject | Re: [PATCH 01/13] acpi: utils: Cleanup acpi_dev_match_cb | From | Suzuki K Poulose <> | Date | Thu, 6 Jun 2019 10:21:38 +0100 |
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Hi Rafael,
On 06/06/2019 10:14, Rafael J. Wysocki wrote: > On Wed, Jun 5, 2019 at 5:14 PM Suzuki K Poulose <suzuki.poulose@arm.com> wrote: >> >> acpi_dev_match_cb match function modifies the "data" argument >> to pass on a result which could be easily deduced from the result >> of the bus_find_device() call at the caller site. Clean this >> up in preparation to convert the "match" argument for bus_find_device >> to accept a "const" data pointer, similar to class_find_device. This >> would allow consolidating the match routines for these two APIs. > > This changelog can be improved IMO.
I agree. Will update it.
> > In fact, the final goal here is to pass (const void *) as the second > argument to acpi_dev_match_cb() (which you could do right away in this > patch if I'm not mistaken) which is because you want to modify the > prototype of bus_find_device(). > > So why don't you write something like this in the changelog: > > "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.
Sure.
> For this reason, update acpi_dev_match_cb() to avoid the redundant > memory updates and change the type of its second argument to (const > void *)."
We can't do that quite yet, until we unify the prototype of the bus_find_device().
>> >> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> >> 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(-) >> >> 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) > > And why not to change the type of the second arg to "const void *data" here?
Because, that would conflict with what bus_find_device() expects now. We make the change only later. Since this change was a bit more intrusive than simply changing the type of the parameter, I kept it as a preparatory patch.
Thanks for the review !
Suzuki
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