On Sun, 27 Oct 2024, Mario Limonciello wrote:
> If for any reason multiple profile handlers don't agree on the profile
> set for the system then the value shown in sysfs can be wrong.
>
> Explicitly check that they match.
>
> Tested-by: Matthew Schwartz <matthew.schwartz@xxxxxxxxx>
> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> ---
> drivers/acpi/platform_profile.c | 61 ++++++++++++++++++++++++---------
> 1 file changed, 45 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
> index db2ebd0393cf7..d22c4eb5f0c36 100644
> --- a/drivers/acpi/platform_profile.c
> +++ b/drivers/acpi/platform_profile.c
> @@ -51,6 +51,45 @@ static unsigned long platform_profile_get_choices(void)
> return seen;
> }
>
> +/* expected to be called under mutex */
Don't add comments like this but enforce it with a lockdep annotation.
"mutex" would have been too vague anyway :-).
> +static int platform_profile_get_active(enum platform_profile_option *profile)
> +{
> + struct platform_profile_handler *handler;
> + enum platform_profile_option active = PLATFORM_PROFILE_LAST;
> + enum platform_profile_option active2 = PLATFORM_PROFILE_LAST;
> + int err;
> +
> + list_for_each_entry(handler, &platform_profile_handler_list, list) {
> + if (active == PLATFORM_PROFILE_LAST)
> + err = handler->profile_get(handler, &active);
> + else
> + err = handler->profile_get(handler, &active2);
> + if (err) {
> + pr_err("Failed to get profile for handler %s\n", handler->name);
> + return err;
> + }
> +
> + if (WARN_ON(active == PLATFORM_PROFILE_LAST))
> + return -EINVAL;
> + if (active2 == PLATFORM_PROFILE_LAST)
> + continue;
> +
> + if (active != active2) {
> + pr_warn("Profile handlers don't agree on current profile\n");
> + return -EINVAL;
> + }
> + active = active2;
This looked very confusing (IMO). How about this:
enum platform_profile_option active = PLATFORM_PROFILE_LAST;
enum platform_profile_option val;
...
err = handler->profile_get(handler, &val);
if (err) {
pr_err(...);
return err;
}
if (WARN_ON(val == PLATFORM_PROFILE_LAST))
return -EINVAL;
if (active != val && active != PLATFORM_PROFILE_LAST) {
pr_warn("Profile handlers don't agree on current profile\n");
return -EINVAL;
}
active = val;
> + }
> +
> + /* Check that profile is valid index */
> + if (WARN_ON((active < 0) || (active >= ARRAY_SIZE(profile_names))))
What does that < 0 check do? Should it be checked right after reading
profile_get()? Or perhaps check both of these right there?
> + return -EIO;
> +
> + *profile = active;
> +
> + return 0;
> +}
> +
> static ssize_t platform_profile_choices_show(struct device *dev,
> struct device_attribute *attr,
> char *buf)
> @@ -80,24 +119,14 @@ static ssize_t platform_profile_show(struct device *dev,
> enum platform_profile_option profile = PLATFORM_PROFILE_BALANCED;
> int err;
>
> - err = mutex_lock_interruptible(&profile_lock);
> - if (err)
> - return err;
> -
> - if (!cur_profile) {
> - mutex_unlock(&profile_lock);
> - return -ENODEV;
> + scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
scoped_cond_guard() conversion should be made in the guard patch?
> + if (!platform_profile_is_registered())
> + return -ENODEV;
> + err = platform_profile_get_active(&profile);
> + if (err)
> + return err;
> }
>
> - err = cur_profile->profile_get(cur_profile, &profile);
> - mutex_unlock(&profile_lock);
> - if (err)
> - return err;
> -
> - /* Check that profile is valid index */
> - if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
> - return -EIO;
> -
> return sysfs_emit(buf, "%s\n", profile_names[profile]);
> }
>
>
--
i.
