diff mbox series

ACPI / device_sysfs: Prefer "compatible" modalias

Message ID 20210122125302.991591-1-kai.heng.feng@canonical.com
State Accepted
Commit 36af2d5c4433fb40ee2af912c4ac0a30991aecfc
Headers show
Series ACPI / device_sysfs: Prefer "compatible" modalias | expand

Commit Message

Kai-Heng Feng Jan. 22, 2021, 12:53 p.m. UTC
Commit 8765c5ba1949 ("ACPI / scan: Rework modalias creation when
"compatible" is present") may create two "MODALIAS=" in uevent file if
conditions are met.

This breaks systemd-udevd, which assumes each "key" in uevent file is
unique. The internal implementation of systemd-udevd overwrites the
first MODALIAS with the second one, so its kmod rule doesn't load driver
for the first MODALIAS.

So if both ACPI modalias and OF modalias are present, use the latter
one to ensure there's only one MODALIAS.

Reference: https://github.com/systemd/systemd/pull/18163
Cc: AceLan Kao <acelan.kao@canonical.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Fixes: 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/acpi/device_sysfs.c | 20 ++++++--------------
 1 file changed, 6 insertions(+), 14 deletions(-)

Comments

Greg KH Jan. 22, 2021, 1:06 p.m. UTC | #1
On Fri, Jan 22, 2021 at 08:53:02PM +0800, Kai-Heng Feng wrote:
> Commit 8765c5ba1949 ("ACPI / scan: Rework modalias creation when
> "compatible" is present") may create two "MODALIAS=" in uevent file if
> conditions are met.
> 
> This breaks systemd-udevd, which assumes each "key" in uevent file is
> unique. The internal implementation of systemd-udevd overwrites the
> first MODALIAS with the second one, so its kmod rule doesn't load driver
> for the first MODALIAS.
> 
> So if both ACPI modalias and OF modalias are present, use the latter
> one to ensure there's only one MODALIAS.
> 
> Reference: https://github.com/systemd/systemd/pull/18163
> Cc: AceLan Kao <acelan.kao@canonical.com>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Fixes: 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present")
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
>  drivers/acpi/device_sysfs.c | 20 ++++++--------------
>  1 file changed, 6 insertions(+), 14 deletions(-)

Thanks for fixing this up!

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rafael J. Wysocki Jan. 25, 2021, 4:08 p.m. UTC | #2
On Fri, Jan 22, 2021 at 2:06 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>

> On Fri, Jan 22, 2021 at 08:53:02PM +0800, Kai-Heng Feng wrote:

> > Commit 8765c5ba1949 ("ACPI / scan: Rework modalias creation when

> > "compatible" is present") may create two "MODALIAS=" in uevent file if

> > conditions are met.

> >

> > This breaks systemd-udevd, which assumes each "key" in uevent file is

> > unique. The internal implementation of systemd-udevd overwrites the

> > first MODALIAS with the second one, so its kmod rule doesn't load driver

> > for the first MODALIAS.

> >

> > So if both ACPI modalias and OF modalias are present, use the latter

> > one to ensure there's only one MODALIAS.

> >

> > Reference: https://github.com/systemd/systemd/pull/18163

> > Cc: AceLan Kao <acelan.kao@canonical.com>

> > Cc: "Rafael J. Wysocki" <rafael@kernel.org>

> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

> > Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> > Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

> > Fixes: 8765c5ba1949 ("ACPI / scan: Rework modalias creation when "compatible" is present")

> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>

> > ---

> >  drivers/acpi/device_sysfs.c | 20 ++++++--------------

> >  1 file changed, 6 insertions(+), 14 deletions(-)

>

> Thanks for fixing this up!

>

> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


Applied as 5.11-rc material with some minor edits in the subject and
changelog and with the tags.

Thanks everyone!
diff mbox series

Patch

diff --git a/drivers/acpi/device_sysfs.c b/drivers/acpi/device_sysfs.c
index 96869f1538b9..bfca116482b8 100644
--- a/drivers/acpi/device_sysfs.c
+++ b/drivers/acpi/device_sysfs.c
@@ -251,20 +251,12 @@  int __acpi_device_uevent_modalias(struct acpi_device *adev,
 	if (add_uevent_var(env, "MODALIAS="))
 		return -ENOMEM;
 
-	len = create_pnp_modalias(adev, &env->buf[env->buflen - 1],
-				  sizeof(env->buf) - env->buflen);
-	if (len < 0)
-		return len;
-
-	env->buflen += len;
-	if (!adev->data.of_compatible)
-		return 0;
-
-	if (len > 0 && add_uevent_var(env, "MODALIAS="))
-		return -ENOMEM;
-
-	len = create_of_modalias(adev, &env->buf[env->buflen - 1],
-				 sizeof(env->buf) - env->buflen);
+	if (adev->data.of_compatible)
+		len = create_of_modalias(adev, &env->buf[env->buflen - 1],
+					 sizeof(env->buf) - env->buflen);
+	else
+		len = create_pnp_modalias(adev, &env->buf[env->buflen - 1],
+					  sizeof(env->buf) - env->buflen);
 	if (len < 0)
 		return len;