[PATCH 0/9] RFKill airplane-mode indicator

This series implements an airplane-mode indicator LED trigger, which can be
used by platform drivers. The default policy have have airplane-mode set when
all the radios known by RFKill are OFF, and unset otherwise. This policy can be
overwritten by userspace using the new operations _AIRPLANE_MODE_ACQUIRE,
_AIRPLANE_MODE_RELEASE, and _AIRPLANE_MODE_CHANGE. When the airplane-mode
indicator state changes, userspace gets notifications through the RFKill
control misc device (/dev/rfkill).

The series also contains a few general fixes and improvements to the subsystem.

João Paulo Rechi Vita (9):
  rfkill: Improve documentation language
  rfkill: Remove extra blank line
  rfkill: Point to the correct deprecated doc location
  rfkill: Move "state" sysfs file back to stable
  rfkill: Factor rfkill_global_states[].cur assignments
  rfkill: Add documentation about LED triggers
  rfkill: Create "rfkill-airplane_mode" LED trigger
  rfkill: Userspace control for airplane mode
  rfkill: Notify userspace of airplane-mode state changes

 Documentation/ABI/obsolete/sysfs-class-rfkill |  20 ----
 Documentation/ABI/stable/sysfs-class-rfkill   |  27 ++++-
 Documentation/rfkill.txt                      |  17 +++
 include/uapi/linux/rfkill.h                   |   3 +
 net/rfkill/core.c                             | 144 +++++++++++++++++++++-----
 5 files changed, 164 insertions(+), 47 deletions(-)
 delete mode 100644 Documentation/ABI/obsolete/sysfs-class-rfkill

-- 
2.5.0

Signed-off-by: João Paulo Rechi Vita <redacted>
---
 net/rfkill/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index a805831..ffbc375 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c

@@ -282,8 +282,8 @@ static void rfkill_set_block(struct rfkill *rfkill, bool blocked)
 	spin_lock_irqsave(&rfkill->lock, flags);
 	if (err) {
 		/*
-		 * Failed -- reset status to _prev, this may be different
-		 * from what set set _PREV to earlier in this function
+		 * Failed -- reset status to _PREV, which may be different
+		 * from what we have set _PREV to earlier in this function
 		 * if rfkill_set_sw_state was invoked.
 		 */
 		if (rfkill->state & RFKILL_BLOCK_SW_PREV)

-- 
2.5.0

Hi João,

On Tue, Feb 9, 2016 at 2:41 AM, João Paulo Rechi Vita [off-list ref] wrote:

Signed-off-by: João Paulo Rechi Vita <jprvita-6IF/jdPJHihWk0Htik3J/w@public.gmane.org>

Looks right to me.

Reviewed-by: Julian Calaby <redacted>

-- 
Julian Calaby

Email: julian.calaby-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Profile: http://www.google.com/profiles/julian.calaby/

Signed-off-by: João Paulo Rechi Vita <redacted>
---
 net/rfkill/core.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index ffbc375..56d79cb 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c

@@ -455,7 +455,6 @@ bool rfkill_get_global_sw_state(const enum rfkill_type type)
 }
 #endif
 
-
 bool rfkill_set_hw_state(struct rfkill *rfkill, bool blocked)
 {
 	unsigned long flags;

-- 
2.5.0

Hi João,

On Tue, Feb 9, 2016 at 2:41 AM, João Paulo Rechi Vita [off-list ref] wrote:

Signed-off-by: João Paulo Rechi Vita <redacted>

Looks sane to me.

Reviewed-by: Julian Calaby <redacted>

-- 
Julian Calaby

Email: julian.calaby@gmail.com
Profile: http://www.google.com/profiles/julian.calaby/

Signed-off-by: João Paulo Rechi Vita <redacted>
---
 Documentation/rfkill.txt |  3 +++
 net/rfkill/core.c        | 13 +++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/Documentation/rfkill.txt b/Documentation/rfkill.txt
index aa6e014..5248812 100644
--- a/Documentation/rfkill.txt
+++ b/Documentation/rfkill.txt

@@ -133,5 +133,8 @@ it available for other applications to take control. Changes to the
 airplane-mode indicator state can be made using RFKILL_OP_AIRPLANE_MODE_CHANGE,
 passing the new value in the 'soft' field of 'struct rfkill_event'.
 
+This same API is also used to provide userspace with notifications of changes
+to airplane-mode indicator state.
+
 
 For further details consult Documentation/ABI/stable/sysfs-class-rfkill.

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 8067701..abbb8f7 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c

@@ -131,7 +131,20 @@ static struct led_trigger rfkill_apm_led_trigger;
 
 static void rfkill_apm_led_trigger_event(bool state)
 {
+	struct rfkill_data *data;
+	struct rfkill_int_event *ev;
+
 	led_trigger_event(&rfkill_apm_led_trigger, state ? LED_FULL : LED_OFF);
+
+	list_for_each_entry(data, &rfkill_fds, list) {
+		ev = kzalloc(sizeof(*ev), GFP_KERNEL);
+		if (!ev)
+			continue;
+		ev->ev.op = RFKILL_OP_AIRPLANE_MODE_CHANGE;
+		ev->ev.soft = state;
+		list_add_tail(&ev->list, &data->events);
+		wake_up_interruptible(&data->read_wait);
+	}
 }
 
 static void rfkill_apm_led_trigger_activate(struct led_classdev *led)

-- 
2.5.0

Provide an interface for the airplane-mode indicator be controlled from
userspace. User has to first acquire the control through
RFKILL_OP_AIRPLANE_MODE_ACQUIRE and keep the fd open for the whole time
it wants to be in control of the indicator. Closing the fd or using
RFKILL_OP_AIRPLANE_MODE_RELEASE restores the default policy.

To change state of the indicator, the RFKILL_OP_AIRPLANE_MODE_CHANGE
operation is used, passing the value on "struct rfkill_event.soft". If
the caller has not acquired the airplane-mode control beforehand, the
operation fails.

Signed-off-by: João Paulo Rechi Vita <jprvita-6IF/jdPJHihWk0Htik3J/w@public.gmane.org>
---
 Documentation/rfkill.txt    | 10 ++++++++++
 include/uapi/linux/rfkill.h |  3 +++
 net/rfkill/core.c           | 47 ++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 57 insertions(+), 3 deletions(-)

diff --git a/Documentation/rfkill.txt b/Documentation/rfkill.txt
index b13025a..aa6e014 100644
--- a/Documentation/rfkill.txt
+++ b/Documentation/rfkill.txt

@@ -87,6 +87,7 @@ RFKill provides per-switch LED triggers, which can be used to drive LEDs
 according to the switch state (LED_FULL when blocked, LED_OFF otherwise).
 An airplane-mode indicator LED trigger is also available, which triggers
 LED_FULL when all radios known by RFKill are blocked, and LED_OFF otherwise.
+The airplane-mode indicator LED trigger policy can be overridden by userspace.
 
 
 5. Userspace support

@@ -123,5 +124,14 @@ RFKILL_TYPE
 The contents of these variables corresponds to the "name", "state" and
 "type" sysfs files explained above.
 
+Userspace can also override the default airplane-mode indicator policy through
+/dev/rfkill. Control of the airplane mode indicator has to be acquired first,
+using RFKILL_OP_AIRPLANE_MODE_ACQUIRE, and is only available for one userspace
+application at a time. Closing the fd or using RFKILL_OP_AIRPLANE_MODE_RELEASE
+reverts the airplane-mode indicator back to the default kernel policy and makes
+it available for other applications to take control. Changes to the
+airplane-mode indicator state can be made using RFKILL_OP_AIRPLANE_MODE_CHANGE,
+passing the new value in the 'soft' field of 'struct rfkill_event'.
+
 
 For further details consult Documentation/ABI/stable/sysfs-class-rfkill.

diff --git a/include/uapi/linux/rfkill.h b/include/uapi/linux/rfkill.h
index 2e00dce..9cb999b 100644
--- a/include/uapi/linux/rfkill.h
+++ b/include/uapi/linux/rfkill.h

@@ -67,6 +67,9 @@ enum rfkill_operation {
 	RFKILL_OP_DEL,
 	RFKILL_OP_CHANGE,
 	RFKILL_OP_CHANGE_ALL,
+	RFKILL_OP_AIRPLANE_MODE_ACQUIRE,
+	RFKILL_OP_AIRPLANE_MODE_RELEASE,
+	RFKILL_OP_AIRPLANE_MODE_CHANGE,
 };
 
 /**

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index fb11547..8067701 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c

@@ -89,6 +89,7 @@ struct rfkill_data {
 	struct mutex		mtx;
 	wait_queue_head_t	read_wait;
 	bool			input_handler;
+	bool			is_apm_owner;
 };
 
 

@@ -123,7 +124,7 @@ static struct {
 } rfkill_global_states[NUM_RFKILL_TYPES];
 
 static bool rfkill_epo_lock_active;
-
+static bool rfkill_apm_owned;
 
 #ifdef CONFIG_RFKILL_LEDS
 static struct led_trigger rfkill_apm_led_trigger;

@@ -350,7 +351,8 @@ static void rfkill_update_global_state(enum rfkill_type type, bool blocked)
 
 	for (i = 0; i < NUM_RFKILL_TYPES; i++)
 		rfkill_global_states[i].cur = blocked;
-	rfkill_apm_led_trigger_event(blocked);
+	if (!rfkill_apm_owned)
+		rfkill_apm_led_trigger_event(blocked);
 }
 
 #ifdef CONFIG_RFKILL_INPUT

@@ -1183,6 +1185,7 @@ static ssize_t rfkill_fop_read(struct file *file, char __user *buf,
 static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *pos)
 {
+	struct rfkill_data *data = file->private_data;
 	struct rfkill *rfkill;
 	struct rfkill_event ev;
 

@@ -1199,7 +1202,7 @@ static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
 	if (copy_from_user(&ev, buf, count))
 		return -EFAULT;
 
-	if (ev.op != RFKILL_OP_CHANGE && ev.op != RFKILL_OP_CHANGE_ALL)
+	if (ev.op < RFKILL_OP_CHANGE)
 		return -EINVAL;
 
 	if (ev.type >= NUM_RFKILL_TYPES)

@@ -1207,6 +1210,34 @@ static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
 
 	mutex_lock(&rfkill_global_mutex);
 
+	if (ev.op == RFKILL_OP_AIRPLANE_MODE_ACQUIRE) {
+		if (rfkill_apm_owned && !data->is_apm_owner) {
+			count = -EACCES;
+		} else {
+			rfkill_apm_owned = true;
+			data->is_apm_owner = true;
+		}
+	}
+
+	if (ev.op == RFKILL_OP_AIRPLANE_MODE_RELEASE) {
+		if (rfkill_apm_owned && !data->is_apm_owner) {
+			count = -EACCES;
+		} else {
+			bool state = rfkill_global_states[RFKILL_TYPE_ALL].cur;
+
+			rfkill_apm_owned = false;
+			data->is_apm_owner = false;
+			rfkill_apm_led_trigger_event(state);
+		}
+	}
+
+	if (ev.op == RFKILL_OP_AIRPLANE_MODE_CHANGE) {
+		if (rfkill_apm_owned && data->is_apm_owner)
+			rfkill_apm_led_trigger_event(ev.soft);
+		else
+			count = -EACCES;
+	}
+
 	if (ev.op == RFKILL_OP_CHANGE_ALL)
 		rfkill_update_global_state(ev.type, ev.soft);
 

@@ -1230,7 +1261,17 @@ static int rfkill_fop_release(struct inode *inode, struct file *file)
 	struct rfkill_int_event *ev, *tmp;
 
 	mutex_lock(&rfkill_global_mutex);
+
+	if (data->is_apm_owner) {
+		bool state = rfkill_global_states[RFKILL_TYPE_ALL].cur;
+
+		rfkill_apm_owned = false;
+		data->is_apm_owner = false;
+		rfkill_apm_led_trigger_event(state);
+	}
+
 	list_del(&data->list);
+
 	mutex_unlock(&rfkill_global_mutex);
 
 	mutex_destroy(&data->mtx);

-- 
2.5.0

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On Mon, 2016-02-08 at 10:41 -0500, João Paulo Rechi Vita wrote:

Provide an interface for the airplane-mode indicator be controlled
from
userspace. User has to first acquire the control through
RFKILL_OP_AIRPLANE_MODE_ACQUIRE and keep the fd open for the whole
time
it wants to be in control of the indicator. Closing the fd or using
RFKILL_OP_AIRPLANE_MODE_RELEASE restores the default policy.

To change state of the indicator, the RFKILL_OP_AIRPLANE_MODE_CHANGE
operation is used, passing the value on "struct rfkill_event.soft".
If
the caller has not acquired the airplane-mode control beforehand, the
operation fails.

I'd like to clarify a bit, so tell me if I'm correct or not.  Using
RFKILL_OP_AIRPLANE_MODE_CHANGE does not actually change any device
state. It's just an indicator with no relationship to any of the
registered rfkill switches, right?

I wonder if setting RFKILL_OP_AIRPLANE_MODE_CHANGE(true) shouldn't also
softblock all switches, otherwise you can set airplane mode all day
long with RFKILL_OP_AIRPLANE_MODE_CHANGE and it doesn't actually enable
airplane mode at all?

Dan

On 8 February 2016 at 11:11, Dan Williams [off-list ref] wrote:

On Mon, 2016-02-08 at 10:41 -0500, João Paulo Rechi Vita wrote:

quoted

Provide an interface for the airplane-mode indicator be controlled
from
userspace. User has to first acquire the control through
RFKILL_OP_AIRPLANE_MODE_ACQUIRE and keep the fd open for the whole
time
it wants to be in control of the indicator. Closing the fd or using
RFKILL_OP_AIRPLANE_MODE_RELEASE restores the default policy.

To change state of the indicator, the RFKILL_OP_AIRPLANE_MODE_CHANGE
operation is used, passing the value on "struct rfkill_event.soft".
If
the caller has not acquired the airplane-mode control beforehand, the
operation fails.

I'd like to clarify a bit, so tell me if I'm correct or not.  Using
RFKILL_OP_AIRPLANE_MODE_CHANGE does not actually change any device
state. It's just an indicator with no relationship to any of the
registered rfkill switches, right?

Yes, that's correct, and it is the intended behavior.

I wonder if setting RFKILL_OP_AIRPLANE_MODE_CHANGE(true) shouldn't also
softblock all switches, otherwise you can set airplane mode all day
long with RFKILL_OP_AIRPLANE_MODE_CHANGE and it doesn't actually enable
airplane mode at all?

The idea behind it is to just provide the mechanism for userspace to
decide what exactly being in airplane mode means, so it would
set/unset the indicator in the right moment.

--
João Paulo Rechi Vita
http://about.me/jprvita

On Mon, 2016-02-08 at 10:11 -0600, Dan Williams wrote:

I'd like to clarify a bit, so tell me if I'm correct or not.  Using
RFKILL_OP_AIRPLANE_MODE_CHANGE does not actually change any device
state. It's just an indicator with no relationship to any of the
registered rfkill switches, right?

Yes. I'm not sure I'm totally happy with this userspace API.

I wonder if setting RFKILL_OP_AIRPLANE_MODE_CHANGE(true) shouldn't
also
softblock all switches, otherwise you can set airplane mode all day
long with RFKILL_OP_AIRPLANE_MODE_CHANGE and it doesn't actually
enable
airplane mode at all?

No, this is kinda the point that you could implement your policy in
userspace now.

johannes

On Wed, 2016-02-10 at 17:07 +0100, Johannes Berg wrote:

On Mon, 2016-02-08 at 10:11 -0600, Dan Williams wrote:

quoted

I'd like to clarify a bit, so tell me if I'm correct or not.  Using
RFKILL_OP_AIRPLANE_MODE_CHANGE does not actually change any device
state. It's just an indicator with no relationship to any of the
registered rfkill switches, right?

Yes. I'm not sure I'm totally happy with this userspace API.

quoted

I wonder if setting RFKILL_OP_AIRPLANE_MODE_CHANGE(true) shouldn't
also
softblock all switches, otherwise you can set airplane mode all day
long with RFKILL_OP_AIRPLANE_MODE_CHANGE and it doesn't actually
enable
airplane mode at all?

No, this is kinda the point that you could implement your policy in
userspace now.

Yeah, I get that now.  It's just that to me, something called
"AIRPLANE_MODE_CHANGE" seems like it should actually change airplane
mode on/off, which implies killing radios.  I wouldn't have had the
problem if it was named AIRPLANE_MODE_INDICATOR_CHANGE, which makes it
clear this is simply an indicator and has no actual effect on anything
other than a LED.

Dan

On 2016-02-10 17:53, Dan Williams wrote:

Yeah, I get that now.  It's just that to me, something called
"AIRPLANE_MODE_CHANGE" seems like it should actually change airplane
mode on/off, which implies killing radios.  I wouldn't have had the
problem if it was named AIRPLANE_MODE_INDICATOR_CHANGE, which makes it
clear this is simply an indicator and has no actual effect on anything
other than a LED.

Yeah, I agree. I'm not even sure that it's a good idea to subsume this 
into the regular operations in the API, although that's obviously the 
easiest extension. I'll need to think about that a bit more with the 
code at hand though.

johannes

On 10 February 2016 at 12:12, Johannes Berg [off-list ref] wrote:

On 2016-02-10 17:53, Dan Williams wrote:

quoted

Yeah, I get that now.  It's just that to me, something called
"AIRPLANE_MODE_CHANGE" seems like it should actually change airplane
mode on/off, which implies killing radios.  I wouldn't have had the
problem if it was named AIRPLANE_MODE_INDICATOR_CHANGE, which makes it
clear this is simply an indicator and has no actual effect on anything
other than a LED.

I also agree the AIRPLANE_MODE_INDICATOR_* prefix makes things more
clear here. Thanks for the feedback, Dan!

Yeah, I agree. I'm not even sure that it's a good idea to subsume this into
the regular operations in the API, although that's obviously the easiest
extension. I'll need to think about that a bit more with the code at hand
though.

Initially I have thought about creating and additional RFKill switch
for that, but I think it would be a bit hackish since we would have to
treat it specially in sysfs attributes and probably other places, and
userspace would also need a special case when going through the list
of RFKill switches in the system. The proposed solution has equivalent
semantics to an RFKill switch, is backward-compatible (users would
only ignore the unknown operations and evens -- although gsd has a
"default:" case to abort execution on an unknown event) and does not
extend the RFKill event struct.

One alternative would be to move the control point to a separate
device, like /dev/rfkill-airplane-mode, but I'm not sure this is a
very elegant approach. Anyway, I'm open to work on changes to the API,
but it would be great if you could at least pick or reject the
non-polemical patches of the series, so I don't need to carry them
anymore.

--
João Paulo Rechi Vita
http://about.me/jprvita

Hi Joa Paulo,

Provide an interface for the airplane-mode indicator be controlled from
userspace. User has to first acquire the control through
RFKILL_OP_AIRPLANE_MODE_ACQUIRE and keep the fd open for the whole time
it wants to be in control of the indicator. Closing the fd or using
RFKILL_OP_AIRPLANE_MODE_RELEASE restores the default policy.

To change state of the indicator, the RFKILL_OP_AIRPLANE_MODE_CHANGE
operation is used, passing the value on "struct rfkill_event.soft". If
the caller has not acquired the airplane-mode control beforehand, the
operation fails.

as explained in an earlier response, the concept Airplane Mode seems to be imposing policy into the kernel. Do we really want have this as a kernel exposed API.

Regards

Marcel

On 2016-02-08 17:20, Marcel Holtmann wrote:

as explained in an earlier response, the concept Airplane Mode seems
to be imposing policy into the kernel. Do we really want have this as
a kernel exposed API.

This patch is the one that *solves* that problem ... please read it more 
carefully?

johannes

Hello Marcel,

On 8 February 2016 at 11:20, Marcel Holtmann [off-list ref] wrote:

Hi Joa Paulo,

quoted

Provide an interface for the airplane-mode indicator be controlled from
userspace. User has to first acquire the control through
RFKILL_OP_AIRPLANE_MODE_ACQUIRE and keep the fd open for the whole time
it wants to be in control of the indicator. Closing the fd or using
RFKILL_OP_AIRPLANE_MODE_RELEASE restores the default policy.

To change state of the indicator, the RFKILL_OP_AIRPLANE_MODE_CHANGE
operation is used, passing the value on "struct rfkill_event.soft". If
the caller has not acquired the airplane-mode control beforehand, the
operation fails.

as explained in an earlier response, the concept Airplane Mode seems to be imposing policy into the kernel. Do we really want have this as a kernel exposed API.

On that very same thread we decided to keep using the "airplane mode"
name both for when having the default policy of "set it when all
radios are off" or when allowing userspace to override the default.
Please see the following message from Johannes
http://www.spinics.net/lists/linux-wireless/msg146069.html and let me
know if that covers your concern.

Thanks!

--
João Paulo Rechi Vita
http://about.me/jprvita

Hi João,

On Tue, Feb 9, 2016 at 2:41 AM, João Paulo Rechi Vita [off-list ref] wrote:

Are you sure this is correct?

In the case that airplane mode isn't owned, the
rfkill_apm_led_trigger_event() call will be a noop, so we should
arguably not be calling it.

Also, should we just fail silently if we're not the owner? I.e. what
does userspace learn from this op failing and is that useful?

Also, this code is duplicated from the _RELEASE op above. Would it
make sense to factor it out into a separate function?

+       }
+
        list_del(&data->list);
+

(extra line)

        mutex_unlock(&rfkill_global_mutex);

        mutex_destroy(&data->mtx);

Thanks,

-- 
Julian Calaby

Email: julian.calaby@gmail.com
Profile: http://www.google.com/profiles/julian.calaby/

On 8 February 2016 at 17:53, Julian Calaby [off-list ref] wrote:

quoted

+       if (ev.op == RFKILL_OP_AIRPLANE_MODE_RELEASE) {
+               if (rfkill_apm_owned && !data->is_apm_owner) {

Are you sure this is correct?

In the case that airplane mode isn't owned, the
rfkill_apm_led_trigger_event() call will be a noop, so we should
arguably not be calling it.

Ok, I'm changing the check to be consistent with _CHANGE, so the call
only succeeds if (rfkill_apm_owned && data->is_apm_owner), and return
an error otherwise.

Also, should we just fail silently if we're not the owner? I.e. what
does userspace learn from this op failing and is that useful?

I think it is better to return an error every time userspace is trying
to call an operation that it was not supposed to call at a certain
state (without acquiring control of the airplane-mode indicator). If a
program has a logic error that makes it call _RELEASE without calling
_ACQUIRE first, it's easier for the programmer to spot the problem if
we return an error here.

quoted

+                       count = -EACCES;
+               } else {
+                       bool state = rfkill_global_states[RFKILL_TYPE_ALL].cur;
+
+                       rfkill_apm_owned = false;
+                       data->is_apm_owner = false;
+                       rfkill_apm_led_trigger_event(state);
+               }
+       }
+
+       if (ev.op == RFKILL_OP_AIRPLANE_MODE_CHANGE) {
+               if (rfkill_apm_owned && data->is_apm_owner)
+                       rfkill_apm_led_trigger_event(ev.soft);
+               else
+                       count = -EACCES;
+       }
+
        if (ev.op == RFKILL_OP_CHANGE_ALL)
                rfkill_update_global_state(ev.type, ev.soft);

@@ -1230,7 +1261,17 @@ static int rfkill_fop_release(struct inode *inode, struct file *file)
        struct rfkill_int_event *ev, *tmp;

        mutex_lock(&rfkill_global_mutex);
+
+       if (data->is_apm_owner) {
+               bool state = rfkill_global_states[RFKILL_TYPE_ALL].cur;
+
+               rfkill_apm_owned = false;
+               data->is_apm_owner = false;
+               rfkill_apm_led_trigger_event(state);

Also, this code is duplicated from the _RELEASE op above. Would it
make sense to factor it out into a separate function?

Yes, makes sense. This also made me notice I was assigning a negative
value to a size_t variable (count).

quoted

+       }
+
        list_del(&data->list);
+

(extra line)

After factoring out the _RELEASE code it looks better without this
additional line.

quoted

        mutex_unlock(&rfkill_global_mutex);

        mutex_destroy(&data->mtx);

Thanks,

Thanks for the review, Julian. I'm sending an updated version.

--
João Paulo Rechi Vita
http://about.me/jprvita

Provide an interface for the airplane-mode indicator be controlled from
userspace. User has to first acquire the control through
RFKILL_OP_AIRPLANE_MODE_ACQUIRE and keep the fd open for the whole time
it wants to be in control of the indicator. Closing the fd or using
RFKILL_OP_AIRPLANE_MODE_RELEASE restores the default policy.

To change state of the indicator, the RFKILL_OP_AIRPLANE_MODE_CHANGE
operation is used, passing the value on "struct rfkill_event.soft". If
the caller has not acquired the airplane-mode control beforehand, the
operation fails.

Signed-off-by: João Paulo Rechi Vita <redacted>
---
 Documentation/rfkill.txt    | 10 ++++++++++
 include/uapi/linux/rfkill.h |  3 +++
 net/rfkill/core.c           | 45 +++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/Documentation/rfkill.txt b/Documentation/rfkill.txt
index b13025a..aa6e014 100644
--- a/Documentation/rfkill.txt
+++ b/Documentation/rfkill.txt

@@ -87,6 +87,7 @@ RFKill provides per-switch LED triggers, which can be used to drive LEDs
 according to the switch state (LED_FULL when blocked, LED_OFF otherwise).
 An airplane-mode indicator LED trigger is also available, which triggers
 LED_FULL when all radios known by RFKill are blocked, and LED_OFF otherwise.
+The airplane-mode indicator LED trigger policy can be overridden by userspace.
 
 
 5. Userspace support

@@ -123,5 +124,14 @@ RFKILL_TYPE
 The contents of these variables corresponds to the "name", "state" and
 "type" sysfs files explained above.
 
+Userspace can also override the default airplane-mode indicator policy through
+/dev/rfkill. Control of the airplane mode indicator has to be acquired first,
+using RFKILL_OP_AIRPLANE_MODE_ACQUIRE, and is only available for one userspace
+application at a time. Closing the fd or using RFKILL_OP_AIRPLANE_MODE_RELEASE
+reverts the airplane-mode indicator back to the default kernel policy and makes
+it available for other applications to take control. Changes to the
+airplane-mode indicator state can be made using RFKILL_OP_AIRPLANE_MODE_CHANGE,
+passing the new value in the 'soft' field of 'struct rfkill_event'.
+
 
 For further details consult Documentation/ABI/stable/sysfs-class-rfkill.

diff --git a/include/uapi/linux/rfkill.h b/include/uapi/linux/rfkill.h
index 2e00dce..9cb999b 100644
--- a/include/uapi/linux/rfkill.h
+++ b/include/uapi/linux/rfkill.h

@@ -67,6 +67,9 @@ enum rfkill_operation {
 	RFKILL_OP_DEL,
 	RFKILL_OP_CHANGE,
 	RFKILL_OP_CHANGE_ALL,
+	RFKILL_OP_AIRPLANE_MODE_ACQUIRE,
+	RFKILL_OP_AIRPLANE_MODE_RELEASE,
+	RFKILL_OP_AIRPLANE_MODE_CHANGE,
 };
 
 /**

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index fb11547..c0da716 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c

@@ -89,6 +89,7 @@ struct rfkill_data {
 	struct mutex		mtx;
 	wait_queue_head_t	read_wait;
 	bool			input_handler;
+	bool			is_apm_owner;
 };
 
 

@@ -123,7 +124,7 @@ static struct {
 } rfkill_global_states[NUM_RFKILL_TYPES];
 
 static bool rfkill_epo_lock_active;
-
+static bool rfkill_apm_owned;
 
 #ifdef CONFIG_RFKILL_LEDS
 static struct led_trigger rfkill_apm_led_trigger;

@@ -350,7 +351,8 @@ static void rfkill_update_global_state(enum rfkill_type type, bool blocked)
 
 	for (i = 0; i < NUM_RFKILL_TYPES; i++)
 		rfkill_global_states[i].cur = blocked;
-	rfkill_apm_led_trigger_event(blocked);
+	if (!rfkill_apm_owned)
+		rfkill_apm_led_trigger_event(blocked);
 }
 
 #ifdef CONFIG_RFKILL_INPUT

@@ -1180,11 +1182,26 @@ static ssize_t rfkill_fop_read(struct file *file, char __user *buf,
 	return ret;
 }
 
+static int rfkill_airplane_mode_release(struct rfkill_data *data)
+{
+	bool state = rfkill_global_states[RFKILL_TYPE_ALL].cur;
+
+	if (rfkill_apm_owned && data->is_apm_owner) {
+		rfkill_apm_owned = false;
+		data->is_apm_owner = false;
+		rfkill_apm_led_trigger_event(state);
+		return 0;
+	}
+	return -EACCES;
+}
+
 static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *pos)
 {
+	struct rfkill_data *data = file->private_data;
 	struct rfkill *rfkill;
 	struct rfkill_event ev;
+	int ret = 0;
 
 	/* we don't need the 'hard' variable but accept it */
 	if (count < RFKILL_EVENT_SIZE_V1 - 1)

@@ -1199,7 +1216,7 @@ static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
 	if (copy_from_user(&ev, buf, count))
 		return -EFAULT;
 
-	if (ev.op != RFKILL_OP_CHANGE && ev.op != RFKILL_OP_CHANGE_ALL)
+	if (ev.op < RFKILL_OP_CHANGE)
 		return -EINVAL;
 
 	if (ev.type >= NUM_RFKILL_TYPES)

@@ -1207,6 +1224,25 @@ static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
 
 	mutex_lock(&rfkill_global_mutex);
 
+	if (ev.op == RFKILL_OP_AIRPLANE_MODE_ACQUIRE) {
+		if (rfkill_apm_owned && !data->is_apm_owner) {
+			ret = -EACCES;
+		} else {
+			rfkill_apm_owned = true;
+			data->is_apm_owner = true;
+		}
+	}
+
+	if (ev.op == RFKILL_OP_AIRPLANE_MODE_RELEASE)
+		ret = rfkill_airplane_mode_release(data);
+
+	if (ev.op == RFKILL_OP_AIRPLANE_MODE_CHANGE) {
+		if (rfkill_apm_owned && data->is_apm_owner)
+			rfkill_apm_led_trigger_event(ev.soft);
+		else
+			ret = -EACCES;
+	}
+
 	if (ev.op == RFKILL_OP_CHANGE_ALL)
 		rfkill_update_global_state(ev.type, ev.soft);
 

@@ -1221,7 +1257,7 @@ static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
 	}
 	mutex_unlock(&rfkill_global_mutex);
 
-	return count;
+	return ret ? ret : count;
 }
 
 static int rfkill_fop_release(struct inode *inode, struct file *file)

@@ -1230,6 +1266,7 @@ static int rfkill_fop_release(struct inode *inode, struct file *file)
 	struct rfkill_int_event *ev, *tmp;
 
 	mutex_lock(&rfkill_global_mutex);
+	rfkill_airplane_mode_release(data);
 	list_del(&data->list);
 	mutex_unlock(&rfkill_global_mutex);
 

-- 
2.5.0

Hi All,

On Wed, Feb 10, 2016 at 8:36 AM, João Paulo Rechi Vita
[off-list ref] wrote:

Provide an interface for the airplane-mode indicator be controlled from
userspace. User has to first acquire the control through
RFKILL_OP_AIRPLANE_MODE_ACQUIRE and keep the fd open for the whole time
it wants to be in control of the indicator. Closing the fd or using
RFKILL_OP_AIRPLANE_MODE_RELEASE restores the default policy.

To change state of the indicator, the RFKILL_OP_AIRPLANE_MODE_CHANGE
operation is used, passing the value on "struct rfkill_event.soft". If
the caller has not acquired the airplane-mode control beforehand, the
operation fails.

Signed-off-by: João Paulo Rechi Vita <redacted>

This looks sane to me.

Reviewed-by: Julian Calaby <redacted>

Thanks,

-- 
Julian Calaby

Email: julian.calaby@gmail.com
Profile: http://www.google.com/profiles/julian.calaby/

This creates a new LED trigger to be used by platform drivers as a
default trigger for airplane-mode indicator LEDs.

By default this trigger will fire when RFKILL_OP_CHANGE_ALL is called
for all types (RFKILL_TYPE_ALL), setting the LED brightness to LED_FULL
when the changing the state to blocked, and to LED_OFF when the changing
the state to unblocked. In the future there will be a mechanism for
userspace to override the default policy, so it can implement its own.

This trigger will be used by the asus-wireless x86 platform driver.

Signed-off-by: João Paulo Rechi Vita <redacted>
---
 Documentation/rfkill.txt |  2 ++
 net/rfkill/core.c        | 49 +++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/Documentation/rfkill.txt b/Documentation/rfkill.txt
index 1f0c270..b13025a 100644
--- a/Documentation/rfkill.txt
+++ b/Documentation/rfkill.txt

@@ -85,6 +85,8 @@ device). Don't do this unless you cannot get the event in any other way.
 
 RFKill provides per-switch LED triggers, which can be used to drive LEDs
 according to the switch state (LED_FULL when blocked, LED_OFF otherwise).
+An airplane-mode indicator LED trigger is also available, which triggers
+LED_FULL when all radios known by RFKill are blocked, and LED_OFF otherwise.
 
 
 5. Userspace support

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 8b96869..fb11547 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c

@@ -126,6 +126,30 @@ static bool rfkill_epo_lock_active;
 
 
 #ifdef CONFIG_RFKILL_LEDS
+static struct led_trigger rfkill_apm_led_trigger;
+
+static void rfkill_apm_led_trigger_event(bool state)
+{
+	led_trigger_event(&rfkill_apm_led_trigger, state ? LED_FULL : LED_OFF);
+}
+
+static void rfkill_apm_led_trigger_activate(struct led_classdev *led)
+{
+	rfkill_apm_led_trigger_event(!rfkill_default_state);
+}
+
+static int rfkill_apm_led_trigger_register(void)
+{
+	rfkill_apm_led_trigger.name = "rfkill-airplane_mode";
+	rfkill_apm_led_trigger.activate = rfkill_apm_led_trigger_activate;
+	return led_trigger_register(&rfkill_apm_led_trigger);
+}
+
+static void rfkill_apm_led_trigger_unregister(void)
+{
+	led_trigger_unregister(&rfkill_apm_led_trigger);
+}
+
 static void rfkill_led_trigger_event(struct rfkill *rfkill)
 {
 	struct led_trigger *trigger;

@@ -177,6 +201,19 @@ static void rfkill_led_trigger_unregister(struct rfkill *rfkill)
 	led_trigger_unregister(&rfkill->led_trigger);
 }
 #else
+static void rfkill_apm_led_trigger_event(bool state)
+{
+}
+
+static int rfkill_apm_led_trigger_register(void)
+{
+	return 0;
+}
+
+static void rfkill_apm_led_trigger_unregister(void)
+{
+}
+
 static void rfkill_led_trigger_event(struct rfkill *rfkill)
 {
 }

@@ -313,6 +350,7 @@ static void rfkill_update_global_state(enum rfkill_type type, bool blocked)
 
 	for (i = 0; i < NUM_RFKILL_TYPES; i++)
 		rfkill_global_states[i].cur = blocked;
+	rfkill_apm_led_trigger_event(blocked);
 }
 
 #ifdef CONFIG_RFKILL_INPUT

@@ -1260,15 +1298,22 @@ static int __init rfkill_init(void)
 {
 	int error;
 
+	error = rfkill_apm_led_trigger_register();
+	if (error)
+		goto out;
+
 	rfkill_update_global_state(RFKILL_TYPE_ALL, !rfkill_default_state);
 
 	error = class_register(&rfkill_class);
-	if (error)
+	if (error) {
+		rfkill_apm_led_trigger_unregister();
 		goto out;
+	}
 
 	error = misc_register(&rfkill_miscdev);
 	if (error) {
 		class_unregister(&rfkill_class);
+		rfkill_apm_led_trigger_unregister();
 		goto out;
 	}
 

@@ -1277,6 +1322,7 @@ static int __init rfkill_init(void)
 	if (error) {
 		misc_deregister(&rfkill_miscdev);
 		class_unregister(&rfkill_class);
+		rfkill_apm_led_trigger_unregister();
 		goto out;
 	}
 #endif

@@ -1293,5 +1339,6 @@ static void __exit rfkill_exit(void)
 #endif
 	misc_deregister(&rfkill_miscdev);
 	class_unregister(&rfkill_class);
+	rfkill_apm_led_trigger_unregister();
 }
 module_exit(rfkill_exit);

-- 
2.5.0

Signed-off-by: João Paulo Rechi Vita <redacted>
---
 Documentation/rfkill.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/rfkill.txt b/Documentation/rfkill.txt
index 2ee6ef9..1f0c270 100644
--- a/Documentation/rfkill.txt
+++ b/Documentation/rfkill.txt

@@ -83,6 +83,8 @@ rfkill drivers that control devices that can be hard-blocked unless they also
 assign the poll_hw_block() callback (then the rfkill core will poll the
 device). Don't do this unless you cannot get the event in any other way.
 
+RFKill provides per-switch LED triggers, which can be used to drive LEDs
+according to the switch state (LED_FULL when blocked, LED_OFF otherwise).
 
 
 5. Userspace support

-- 
2.5.0

Factor all assignments to rfkill_global_states[].cur into a single
function rfkill_update_global_state().

Signed-off-by: João Paulo Rechi Vita <redacted>
---
 net/rfkill/core.c | 38 +++++++++++++++++---------------------
 1 file changed, 17 insertions(+), 21 deletions(-)

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 56d79cb..8b96869 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c

@@ -302,6 +302,19 @@ static void rfkill_set_block(struct rfkill *rfkill, bool blocked)
 		rfkill_event(rfkill);
 }
 
+static void rfkill_update_global_state(enum rfkill_type type, bool blocked)
+{
+	int i;
+
+	if (type != RFKILL_TYPE_ALL) {
+		rfkill_global_states[type].cur = blocked;
+		return;
+	}
+
+	for (i = 0; i < NUM_RFKILL_TYPES; i++)
+		rfkill_global_states[i].cur = blocked;
+}
+
 #ifdef CONFIG_RFKILL_INPUT
 static atomic_t rfkill_input_disabled = ATOMIC_INIT(0);
 

@@ -319,15 +332,7 @@ static void __rfkill_switch_all(const enum rfkill_type type, bool blocked)
 {
 	struct rfkill *rfkill;
 
-	if (type == RFKILL_TYPE_ALL) {
-		int i;
-
-		for (i = 0; i < NUM_RFKILL_TYPES; i++)
-			rfkill_global_states[i].cur = blocked;
-	} else {
-		rfkill_global_states[type].cur = blocked;
-	}
-
+	rfkill_update_global_state(type, blocked);
 	list_for_each_entry(rfkill, &rfkill_list, node) {
 		if (rfkill->type != type && type != RFKILL_TYPE_ALL)
 			continue;

@@ -1164,15 +1169,8 @@ static ssize_t rfkill_fop_write(struct file *file, const char __user *buf,
 
 	mutex_lock(&rfkill_global_mutex);
 
-	if (ev.op == RFKILL_OP_CHANGE_ALL) {
-		if (ev.type == RFKILL_TYPE_ALL) {
-			enum rfkill_type i;
-			for (i = 0; i < NUM_RFKILL_TYPES; i++)
-				rfkill_global_states[i].cur = ev.soft;
-		} else {
-			rfkill_global_states[ev.type].cur = ev.soft;
-		}
-	}
+	if (ev.op == RFKILL_OP_CHANGE_ALL)
+		rfkill_update_global_state(ev.type, ev.soft);
 
 	list_for_each_entry(rfkill, &rfkill_list, node) {
 		if (rfkill->idx != ev.idx && ev.op != RFKILL_OP_CHANGE_ALL)

@@ -1261,10 +1259,8 @@ static struct miscdevice rfkill_miscdev = {
 static int __init rfkill_init(void)
 {
 	int error;
-	int i;
 
-	for (i = 0; i < NUM_RFKILL_TYPES; i++)
-		rfkill_global_states[i].cur = !rfkill_default_state;
+	rfkill_update_global_state(RFKILL_TYPE_ALL, !rfkill_default_state);
 
 	error = class_register(&rfkill_class);
 	if (error)

-- 
2.5.0

Hi João,

On Tue, Feb 9, 2016 at 2:41 AM, João Paulo Rechi Vita [off-list ref] wrote:

Factor all assignments to rfkill_global_states[].cur into a single
function rfkill_update_global_state().

Signed-off-by: João Paulo Rechi Vita <jprvita-6IF/jdPJHihWk0Htik3J/w@public.gmane.org>

Looks sane to me.

Reviewed-by: Julian Calaby <redacted>

-- 
Julian Calaby

Email: julian.calaby-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Profile: http://www.google.com/profiles/julian.calaby/

There is still quite a bit of code using this interface, so we can't
just remove it. Hopefully it will be possible in the future, but since
its scheduled removal date is past 2 years already, we are better having
the documentation reflecting the current state of things.

Signed-off-by: João Paulo Rechi Vita <redacted>
---
 Documentation/ABI/obsolete/sysfs-class-rfkill | 20 --------------------
 Documentation/ABI/stable/sysfs-class-rfkill   | 25 ++++++++++++++++++++++---
 2 files changed, 22 insertions(+), 23 deletions(-)
 delete mode 100644 Documentation/ABI/obsolete/sysfs-class-rfkill

diff --git a/Documentation/ABI/obsolete/sysfs-class-rfkill b/Documentation/ABI/obsolete/sysfs-class-rfkill
deleted file mode 100644
index e736d14..0000000
--- a/Documentation/ABI/obsolete/sysfs-class-rfkill
+++ /dev/null

@@ -1,20 +0,0 @@
-rfkill - radio frequency (RF) connector kill switch support
-
-For details to this subsystem look at Documentation/rfkill.txt.
-
-What:		/sys/class/rfkill/rfkill[0-9]+/state
-Date:		09-Jul-2007
-KernelVersion	v2.6.22
-Contact:	linux-wireless@vger.kernel.org
-Description: 	Current state of the transmitter.
-		This file is deprecated and scheduled to be removed in 2014,
-		because its not possible to express the 'soft and hard block'
-		state of the rfkill driver.
-Values: 	A numeric value.
-		0: RFKILL_STATE_SOFT_BLOCKED
-			transmitter is turned off by software
-		1: RFKILL_STATE_UNBLOCKED
-			transmitter is (potentially) active
-		2: RFKILL_STATE_HARD_BLOCKED
-			transmitter is forced off by something outside of
-			the driver's control.

diff --git a/Documentation/ABI/stable/sysfs-class-rfkill b/Documentation/ABI/stable/sysfs-class-rfkill
index e51571e..e1ba4a1 100644
--- a/Documentation/ABI/stable/sysfs-class-rfkill
+++ b/Documentation/ABI/stable/sysfs-class-rfkill

@@ -5,9 +5,6 @@ For details to this subsystem look at Documentation/rfkill.txt.
 For the deprecated /sys/class/rfkill/*/claim knobs of this interface look in
 Documentation/ABI/removed/sysfs-class-rfkill.
 
-For the deprecated /sys/class/rfkill/*/state knobs of this interface look in
-Documentation/ABI/obsolete/sysfs-class-rfkill.
-
 What: 		/sys/class/rfkill
 Date:		09-Jul-2007
 KernelVersion:	v2.6.22

@@ -44,6 +41,28 @@ Values: 	A numeric value.
 		1: true
 
 
+What:		/sys/class/rfkill/rfkill[0-9]+/state
+Date:		09-Jul-2007
+KernelVersion	v2.6.22
+Contact:	linux-wireless@vger.kernel.org
+Description: 	Current state of the transmitter.
+		This file was scheduled to be removed in 2014, but due to its
+		large number of users it will be sticking around for a bit
+		longer. Despite it being marked as stabe, the newer "hard" and
+		"soft" interfaces should be preffered, since it is not possible
+		to express the 'soft and hard block' state of the rfkill driver
+		through this interface. There will likely be another attempt to
+		remove it in the future.
+Values: 	A numeric value.
+		0: RFKILL_STATE_SOFT_BLOCKED
+			transmitter is turned off by software
+		1: RFKILL_STATE_UNBLOCKED
+			transmitter is (potentially) active
+		2: RFKILL_STATE_HARD_BLOCKED
+			transmitter is forced off by something outside of
+			the driver's control.
+
+
 What:		/sys/class/rfkill/rfkill[0-9]+/hard
 Date:		12-March-2010
 KernelVersion	v2.6.34

-- 
2.5.0

The "claim" sysfs interface has been removed, so its documentation now
lives in the "removed" folder.

Signed-off-by: João Paulo Rechi Vita <redacted>
---
 Documentation/ABI/stable/sysfs-class-rfkill | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/stable/sysfs-class-rfkill b/Documentation/ABI/stable/sysfs-class-rfkill
index 097f522..e51571e 100644
--- a/Documentation/ABI/stable/sysfs-class-rfkill
+++ b/Documentation/ABI/stable/sysfs-class-rfkill

@@ -2,8 +2,10 @@ rfkill - radio frequency (RF) connector kill switch support
 
 For details to this subsystem look at Documentation/rfkill.txt.
 
-For the deprecated /sys/class/rfkill/*/state and
-/sys/class/rfkill/*/claim knobs of this interface look in
+For the deprecated /sys/class/rfkill/*/claim knobs of this interface look in
+Documentation/ABI/removed/sysfs-class-rfkill.
+
+For the deprecated /sys/class/rfkill/*/state knobs of this interface look in
 Documentation/ABI/obsolete/sysfs-class-rfkill.
 
 What: 		/sys/class/rfkill

-- 
2.5.0

Hi João,

On Tue, Feb 9, 2016 at 2:41 AM, João Paulo Rechi Vita [off-list ref] wrote:

The "claim" sysfs interface has been removed, so its documentation now
lives in the "removed" folder.

Signed-off-by: João Paulo Rechi Vita <redacted>

Looks right to me.

Reviewed-by: Julian Calaby <redacted>

-- 
Julian Calaby

Email: julian.calaby@gmail.com
Profile: http://www.google.com/profiles/julian.calaby/