** Description changed:
[ Impact ]
The existing 'new_device' interface for gpio-aggregator
(https://docs.kernel.org/admin-guide/gpio/gpio-aggregator.html) has several
limitations:
* No way to determine when GPIO aggregator creation is complete.
* No way to retrieve errors when creating a GPIO aggregator.
* No way to trace a GPIO line of an aggregator back to its corresponding
physical device.
* The 'new_device' echo does not indicate which virtual gpiochip<N> was
created.
* No way to assign names to GPIO lines exported through an aggregator.
While the GPIO aggregator concept is useful for resource isolation,
these limitations currently hinder its practical effectiveness. This
patch series addresses all those issues.
[ Fix ]
- Apply 12 patches in total:
+ For Plucky, I cherry-picked the v6 patch series [1] to include it in the
+ Release before the main patch series reached linux-next. See the APPLIED
+ announcement [2]. As a result, the code differs slightly from the v7 patch
+ series [3], which later made it to linux-next and was used for backporting to
+ Oracular/Noble/Jammy as explained below. However, since there are no
+ substantial differences between v6 and v7, I do not intend to modify Plucky to
+ match v7.
- * Apply [PATCH 1/3] to [PATCH 3/3] from [1], which have landed in
linux-next.
- * Add a "UBUNTU: [Config]" commit for the new config option
CONFIG_DEV_SYNC_PROBE.
- * Apply [PATCH 2/9] to [PATCH 9/9] from [2], which are under review.
+ For Plucky, (already) applied 12 patches in total:
- [1]
https://lore.kernel.org/all/20250221133501.2203897-1-koichiro....@canonical.com/
- [2]
https://lore.kernel.org/all/20250315164123.1855142-1-koichiro....@canonical.com/
+ * Applied [PATCH 1/3] to [PATCH 3/3] from [4], which had landed in
linux-next.
+ * Applied [PATCH 2/9] to [PATCH 9/9] from [1], which had been under review.
+ * Added a "UBUNTU: [Config]" commit for the new config option
CONFIG_DEV_SYNC_PROBE.
- Note:
- - [1] is a preparatory patch series for [2].
- - [PATCH 1/9] from [2] was already picked and landed in mainline.
+ Note:
+ - [4] is a preparatory patch series for [1].
+ - [PATCH 1/9] from [1] was already picked and landed in mainline.
+
+ For Oracular, apply 13 patches in total:
+
+ * Cherry-pick 3 commits from mainline, as prerequisite for the main patch
series:
+ eb5ab6ffb4ca ("gpio: introduce utilities for synchronous fake device
creation")
+ 22dec5aa596e ("gpio: aggregator: simplify aggr_parse() with scoped
bitmap")
+ 12f65d120350 ("gpio: aggregator: protect driver attr handlers against
module unload")
+ * Cherry-pick 9 commits from linux-next:
+ 7a56efeabffd ("gpio: aggregator: reorder functions to prepare for
configfs introduction")
+ 7616dd97ae22 ("gpio: aggregator: unify function naming")
+ 88fe1d1a646b ("gpio: aggregator: add gpio_aggregator_{alloc,free}()")
+ 86f162e73d2d ("gpio: aggregator: introduce basic configfs interface")
+ 4ec2315d7fab ("gpio: aggregator: rename 'name' to 'key' in
gpio_aggregator_parse()")
+ 83c8e3df642f ("gpio: aggregator: expose aggregator created via legacy
sysfs to configfs")
+ 0269c768de1b ("gpio: aggregator: cancel deferred probe for devices
created via configfs")
+ 10f94d092bba ("Documentation: gpio: document configfs interface for
gpio-aggregator")
+ 6d7f0c1103ef ("selftests: gpio: add test cases for gpio-aggregator")
+ * Add a "UBUNTU: [Config]" commit for the new config option
CONFIG_DEV_SYNC_PROBE.
+
+ For Noble, apply 14 patches in total:
+
+ * Cherry-pick 4 commits from mainline, as prerequisite for the main patch
series:
+ eb5ab6ffb4ca ("gpio: introduce utilities for synchronous fake device
creation")
+ d12a82848eac ("bitmap: Define a cleanup function for bitmaps")
+ 22dec5aa596e ("gpio: aggregator: simplify aggr_parse() with scoped
bitmap")
+ 12f65d120350 ("gpio: aggregator: protect driver attr handlers against
module unload")
+ * Cherry-pick 9 commits from linux-next:
+ 7a56efeabffd ("gpio: aggregator: reorder functions to prepare for
configfs introduction")
+ 7616dd97ae22 ("gpio: aggregator: unify function naming")
+ 88fe1d1a646b ("gpio: aggregator: add gpio_aggregator_{alloc,free}()")
+ 86f162e73d2d ("gpio: aggregator: introduce basic configfs interface")
+ 4ec2315d7fab ("gpio: aggregator: rename 'name' to 'key' in
gpio_aggregator_parse()")
+ 83c8e3df642f ("gpio: aggregator: expose aggregator created via legacy
sysfs to configfs")
+ 0269c768de1b ("gpio: aggregator: cancel deferred probe for devices
created via configfs")
+ 10f94d092bba ("Documentation: gpio: document configfs interface for
gpio-aggregator")
+ 6d7f0c1103ef ("selftests: gpio: add test cases for gpio-aggregator")
+ * Add a "UBUNTU: [Config]" commit for the new config option
CONFIG_DEV_SYNC_PROBE.
+
+ For Jammy, apply 12 patches in total:
+
+ * Cherry-pick/Backport 3 commits from mainline, as prerequisite for the
main patch series:
+ eb5ab6ffb4ca ("gpio: introduce utilities for synchronous fake device
creation") [5]
+ 95b39792c664 ("gpio: aggregator: Stop using ARCH_NR_GPIOS")
+ 39ebbd52b73d ("gpio: aggregator: Add missing header(s)")
+ * Cherry-pick/Backport 8 commits from linux-next:
+ 7a56efeabffd ("gpio: aggregator: reorder functions to prepare for
configfs introduction") [5]
+ 7616dd97ae22 ("gpio: aggregator: unify function naming")
+ 88fe1d1a646b ("gpio: aggregator: add gpio_aggregator_{alloc,free}()") [5]
+ 86f162e73d2d ("gpio: aggregator: introduce basic configfs interface") [5]
+ 4ec2315d7fab ("gpio: aggregator: rename 'name' to 'key' in
gpio_aggregator_parse()") [5]
+ 83c8e3df642f ("gpio: aggregator: expose aggregator created via legacy
sysfs to configfs") [5]
+ 0269c768de1b ("gpio: aggregator: cancel deferred probe for devices
created via configfs")
+ 10f94d092bba ("Documentation: gpio: document configfs interface for
gpio-aggregator")
+ * Add a "UBUNTU: [Config]" commit for the new config option
CONFIG_DEV_SYNC_PROBE.
+
+ [1]
https://lore.kernel.org/all/20250315164123.1855142-1-koichiro....@canonical.com/
+ [2] https://lists.ubuntu.com/archives/kernel-team/2025-March/158315.html
+ [3]
https://lore.kernel.org/all/20250407043019.4105613-1-koichiro....@canonical.com/
+ [4]
https://lore.kernel.org/all/20250221133501.2203897-1-koichiro....@canonical.com/
+ [5] Some adjustments were needed (i.e. backporting). The details are explained
+ in the commit message trailers.
[ Test Plan ]
- Run kselftest.
+ For Plucky/Oracular/Noble, run kselftest.
+
+ For Jammy, either test (play) on real hardware or run kselftest from:
+ https://git.launchpad.net/~koichiroden/+git/jammy (branch:
+ kselftest-for-gpio-aggr-configfs-backport-to-jammy).
+
+ N.B. kselftest for gpio-aggregator is unavailable due to the missing gpio-sim
+ on Jammy, and this SRU patch submission does not backport it, as doing so
would
+ be excessive.
[ Where problems could occur ]
Any regressions would only impact users who load and use the
gpio-aggregator module, potentially causing issues like memory leaks or
system crashes.
** Also affects: linux (Ubuntu Jammy)
Importance: Undecided
Status: New
** Changed in: linux (Ubuntu Jammy)
Assignee: (unassigned) => Koichiro Den (koichiroden)
** Changed in: linux (Ubuntu Jammy)
Status: New => In Progress
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https://bugs.launchpad.net/bugs/2103496
Title:
Introduce configfs-based interface for gpio-aggregator
Status in linux package in Ubuntu:
Fix Released
Status in linux source package in Jammy:
In Progress
Status in linux source package in Noble:
In Progress
Status in linux source package in Oracular:
In Progress
Status in linux source package in Plucky:
Fix Released
Bug description:
[ Impact ]
The existing 'new_device' interface for gpio-aggregator
(https://docs.kernel.org/admin-guide/gpio/gpio-aggregator.html) has several
limitations:
* No way to determine when GPIO aggregator creation is complete.
* No way to retrieve errors when creating a GPIO aggregator.
* No way to trace a GPIO line of an aggregator back to its corresponding
physical device.
* The 'new_device' echo does not indicate which virtual gpiochip<N> was
created.
* No way to assign names to GPIO lines exported through an aggregator.
While the GPIO aggregator concept is useful for resource isolation,
these limitations currently hinder its practical effectiveness. This
patch series addresses all those issues.
[ Fix ]
For Plucky, I cherry-picked the v6 patch series [1] to include it in the
Release before the main patch series reached linux-next. See the APPLIED
announcement [2]. As a result, the code differs slightly from the v7 patch
series [3], which later made it to linux-next and was used for backporting to
Oracular/Noble/Jammy as explained below. However, since there are no
substantial differences between v6 and v7, I do not intend to modify Plucky to
match v7.
For Plucky, (already) applied 12 patches in total:
* Applied [PATCH 1/3] to [PATCH 3/3] from [4], which had landed in
linux-next.
* Applied [PATCH 2/9] to [PATCH 9/9] from [1], which had been under review.
* Added a "UBUNTU: [Config]" commit for the new config option
CONFIG_DEV_SYNC_PROBE.
Note:
- [4] is a preparatory patch series for [1].
- [PATCH 1/9] from [1] was already picked and landed in mainline.
For Oracular, apply 13 patches in total:
* Cherry-pick 3 commits from mainline, as prerequisite for the main patch
series:
eb5ab6ffb4ca ("gpio: introduce utilities for synchronous fake device
creation")
22dec5aa596e ("gpio: aggregator: simplify aggr_parse() with scoped
bitmap")
12f65d120350 ("gpio: aggregator: protect driver attr handlers against
module unload")
* Cherry-pick 9 commits from linux-next:
7a56efeabffd ("gpio: aggregator: reorder functions to prepare for
configfs introduction")
7616dd97ae22 ("gpio: aggregator: unify function naming")
88fe1d1a646b ("gpio: aggregator: add gpio_aggregator_{alloc,free}()")
86f162e73d2d ("gpio: aggregator: introduce basic configfs interface")
4ec2315d7fab ("gpio: aggregator: rename 'name' to 'key' in
gpio_aggregator_parse()")
83c8e3df642f ("gpio: aggregator: expose aggregator created via legacy
sysfs to configfs")
0269c768de1b ("gpio: aggregator: cancel deferred probe for devices
created via configfs")
10f94d092bba ("Documentation: gpio: document configfs interface for
gpio-aggregator")
6d7f0c1103ef ("selftests: gpio: add test cases for gpio-aggregator")
* Add a "UBUNTU: [Config]" commit for the new config option
CONFIG_DEV_SYNC_PROBE.
For Noble, apply 14 patches in total:
* Cherry-pick 4 commits from mainline, as prerequisite for the main patch
series:
eb5ab6ffb4ca ("gpio: introduce utilities for synchronous fake device
creation")
d12a82848eac ("bitmap: Define a cleanup function for bitmaps")
22dec5aa596e ("gpio: aggregator: simplify aggr_parse() with scoped
bitmap")
12f65d120350 ("gpio: aggregator: protect driver attr handlers against
module unload")
* Cherry-pick 9 commits from linux-next:
7a56efeabffd ("gpio: aggregator: reorder functions to prepare for
configfs introduction")
7616dd97ae22 ("gpio: aggregator: unify function naming")
88fe1d1a646b ("gpio: aggregator: add gpio_aggregator_{alloc,free}()")
86f162e73d2d ("gpio: aggregator: introduce basic configfs interface")
4ec2315d7fab ("gpio: aggregator: rename 'name' to 'key' in
gpio_aggregator_parse()")
83c8e3df642f ("gpio: aggregator: expose aggregator created via legacy
sysfs to configfs")
0269c768de1b ("gpio: aggregator: cancel deferred probe for devices
created via configfs")
10f94d092bba ("Documentation: gpio: document configfs interface for
gpio-aggregator")
6d7f0c1103ef ("selftests: gpio: add test cases for gpio-aggregator")
* Add a "UBUNTU: [Config]" commit for the new config option
CONFIG_DEV_SYNC_PROBE.
For Jammy, apply 12 patches in total:
* Cherry-pick/Backport 3 commits from mainline, as prerequisite for the
main patch series:
eb5ab6ffb4ca ("gpio: introduce utilities for synchronous fake device
creation") [5]
95b39792c664 ("gpio: aggregator: Stop using ARCH_NR_GPIOS")
39ebbd52b73d ("gpio: aggregator: Add missing header(s)")
* Cherry-pick/Backport 8 commits from linux-next:
7a56efeabffd ("gpio: aggregator: reorder functions to prepare for
configfs introduction") [5]
7616dd97ae22 ("gpio: aggregator: unify function naming")
88fe1d1a646b ("gpio: aggregator: add gpio_aggregator_{alloc,free}()") [5]
86f162e73d2d ("gpio: aggregator: introduce basic configfs interface") [5]
4ec2315d7fab ("gpio: aggregator: rename 'name' to 'key' in
gpio_aggregator_parse()") [5]
83c8e3df642f ("gpio: aggregator: expose aggregator created via legacy
sysfs to configfs") [5]
0269c768de1b ("gpio: aggregator: cancel deferred probe for devices
created via configfs")
10f94d092bba ("Documentation: gpio: document configfs interface for
gpio-aggregator")
* Add a "UBUNTU: [Config]" commit for the new config option
CONFIG_DEV_SYNC_PROBE.
[1]
https://lore.kernel.org/all/20250315164123.1855142-1-koichiro....@canonical.com/
[2] https://lists.ubuntu.com/archives/kernel-team/2025-March/158315.html
[3]
https://lore.kernel.org/all/20250407043019.4105613-1-koichiro....@canonical.com/
[4]
https://lore.kernel.org/all/20250221133501.2203897-1-koichiro....@canonical.com/
[5] Some adjustments were needed (i.e. backporting). The details are explained
in the commit message trailers.
[ Test Plan ]
For Plucky/Oracular/Noble, run kselftest.
For Jammy, either test (play) on real hardware or run kselftest from:
https://git.launchpad.net/~koichiroden/+git/jammy (branch:
kselftest-for-gpio-aggr-configfs-backport-to-jammy).
N.B. kselftest for gpio-aggregator is unavailable due to the missing gpio-sim
on Jammy, and this SRU patch submission does not backport it, as doing so
would
be excessive.
[ Where problems could occur ]
Any regressions would only impact users who load and use the
gpio-aggregator module, potentially causing issues like memory leaks or
system crashes.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2103496/+subscriptions
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