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leds: trigger: Add led trigger for bpf

PATCH Superseded Daniel Hodges 6 participants 16 messages Mar 22, 2024 – Apr 11, 2024

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Daniel Hodges

author
#0 lore raw

cover leds: trigger: Add led trigger for bpf

This patch set adds a new led trigger that uses the bpf subsystem for triggering leds. It is designed to be used in conjunction with a bpf program(s) that can modify led state through the use of bpf kfuncs. This is useful for providing a physical indication that a some event has occurred. In the context of bpf this could range from handling a packet to hitting a tracepoint.

Daniel Hodges (3):
leds: trigger: legtrig-bpf: Add ledtrig-bpf module selftests/bpf: Add selftests for bpf led programs
leds: trigger: Add documentation for ledtrig-bpf

 Documentation/leds/index.rst                  |  1 +
 Documentation/leds/ledtrig-bpf.rst            | 13 ++++
 drivers/leds/trigger/Kconfig                  | 10 +++
 drivers/leds/trigger/Makefile                 |  1 +
 drivers/leds/trigger/ledtrig-bpf.c            | 72 +++++++++++++++++++
 tools/testing/selftests/bpf/config            |  1 +
 .../testing/selftests/bpf/progs/ledtrig_bpf.c | 28 ++++++++
 7 files changed, 126 insertions(+)
 create mode 100644 Documentation/leds/ledtrig-bpf.rst
 create mode 100644 drivers/leds/trigger/ledtrig-bpf.c
 create mode 100644 tools/testing/selftests/bpf/progs/ledtrig_bpf.c
Signature · 1 line
2.43.0
author
#1 lore raw

PATCH 1/3 leds: trigger: legtrig-bpf: Add ledtrig-bpf module

This patch adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity through calling bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point.

Signed-off-by Daniel Hodges <[email protected]>
---
 drivers/leds/trigger/Kconfig       | 10 +++++
 drivers/leds/trigger/Makefile      |  1 +
 drivers/leds/trigger/ledtrig-bpf.c | 72 ++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+)
 create mode 100644 drivers/leds/trigger/ledtrig-bpf.c
drivers/leds/trigger/Kconfig +10 -0
index d11d80176fc0..30b0fd3847be 100644
@@ -152,4 +152,14 @@ config LEDS_TRIGGER_TTY
 
 	  When build as a module this driver will be called ledtrig-tty.
 
+config LEDS_TRIGGER_BPF
+	tristate "LED BPF Trigger"
+	depends on BPF
+	depends on BPF_SYSCALL
+	help
+	  This allows LEDs to be controlled by the BPF subsystem. This trigger
+	  must be used with a loaded BPF program in order to control LED state.
+	  BPF programs can control LED state with kfuncs.
+	  If unsure, say N.
+
 endif # LEDS_TRIGGERS
drivers/leds/trigger/Makefile +1 -0
index 25c4db97cdd4..ac47128d406c 100644
@@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
 obj-$(CONFIG_LEDS_TRIGGER_PATTERN)	+= ledtrig-pattern.o
 obj-$(CONFIG_LEDS_TRIGGER_AUDIO)	+= ledtrig-audio.o
 obj-$(CONFIG_LEDS_TRIGGER_TTY)		+= ledtrig-tty.o
+obj-$(CONFIG_LEDS_TRIGGER_BPF)		+= ledtrig-bpf.o
drivers/leds/trigger/ledtrig-bpf.c new file +72 -0

72 lines not on this page · raw message

Signature · 1 line
2.43.0
reviewer
#2 lore raw

Re: [PATCH 1/3] leds: trigger: legtrig-bpf: Add ledtrig-bpf module

Quoted 79 lines · Daniel Hodges

This patch adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity through calling bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point.

Signed-off-by Daniel Hodges <[email protected]>
---
  drivers/leds/trigger/Kconfig       | 10 +++++
  drivers/leds/trigger/Makefile      |  1 +
  drivers/leds/trigger/ledtrig-bpf.c | 72 ++++++++++++++++++++++++++++++
  3 files changed, 83 insertions(+)

create mode 100644 drivers/leds/trigger/ledtrig-bpf.c

drivers/leds/trigger/Kconfig +10 -0
index d11d80176fc0..30b0fd3847be 100644
@@ -152,4 +152,14 @@ config LEDS_TRIGGER_TTY
 
  	  When build as a module this driver will be called ledtrig-tty.
 
+config LEDS_TRIGGER_BPF
+	tristate "LED BPF Trigger"
+	depends on BPF
+	depends on BPF_SYSCALL
+	help
+	  This allows LEDs to be controlled by the BPF subsystem. This trigger
+	  must be used with a loaded BPF program in order to control LED state.
+	  BPF programs can control LED state with kfuncs.
+	  If unsure, say N.
+
  endif # LEDS_TRIGGERS
drivers/leds/trigger/Makefile +1 -0
index 25c4db97cdd4..ac47128d406c 100644
@@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
  obj-$(CONFIG_LEDS_TRIGGER_PATTERN)	+= ledtrig-pattern.o
  obj-$(CONFIG_LEDS_TRIGGER_AUDIO)	+= ledtrig-audio.o
  obj-$(CONFIG_LEDS_TRIGGER_TTY)		+= ledtrig-tty.o
+obj-$(CONFIG_LEDS_TRIGGER_BPF)		+= ledtrig-bpf.o
drivers/leds/trigger/ledtrig-bpf.c new file +31 -0
new file mode 100644
index 000000000000..e3b0b8281b70
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LED BPF Trigger
+ *
+ * Author: Daniel Hodges <[email protected]>
+ */
+
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/btf_ids.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+
+
+DEFINE_LED_TRIGGER(ledtrig_bpf);
+
+__bpf_hook_start()
+
+__bpf_kfunc void bpf_ledtrig_blink(unsigned long delay_on, unsigned long delay_off, int invert)
+{
+	led_trigger_blink_oneshot(ledtrig_bpf, delay_on, delay_off, invert);
+}
+__bpf_hook_end();
+
+BTF_SET8_START(ledtrig_bpf_kfunc_ids)
+BTF_ID_FLAGS(func, bpf_ledtrig_blink)
+BTF_SET8_END(ledtrig_bpf_kfunc_ids)
+
+static const struct btf_kfunc_id_set ledtrig_bpf_kfunc_set = {

drivers/leds/trigger/ledtrig-bpf.c line 41

Quoted 10 lines
drivers/leds/trigger/ledtrig-bpf.c new file +10 -0
+	.owner = THIS_MODULE,
+	.set   = &ledtrig_bpf_kfunc_ids,
+};
+
+static int init_bpf(void)
+{
+	int ret;
+
+	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC,
+			&ledtrig_bpf_kfunc_set);

If you add the kfunc to BPF_PROG_TYPE_UNSPEC, then you do not need to add to the following prog types since the kernel will search BPF_PROG_TYPE_UNSPEC for all prog types.

But if the kfunc only intends to be used for the following program types, I suggest removing the above BPF_PROG_TYPE_UNSPEC registration.

Quoted 31 lines
drivers/leds/trigger/ledtrig-bpf.c new file +31 -0
+	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING,
+			&ledtrig_bpf_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL,
+			&ledtrig_bpf_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SK_SKB,
+			&ledtrig_bpf_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS,
+			&ledtrig_bpf_kfunc_set);
+	ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_ACT,
+			&ledtrig_bpf_kfunc_set);
+	return ret;
+}
+
+static int ledtrig_bpf_init(void)
+{
+	led_trigger_register_simple("bpf", &ledtrig_bpf);
+
+	return init_bpf();
+}
+
+static void __exit ledtrig_bpf_exit(void)
+{
+	led_trigger_unregister_simple(ledtrig_bpf);
+}
+
+module_init(ledtrig_bpf_init);
+module_exit(ledtrig_bpf_exit);
+
+MODULE_AUTHOR("Daniel Hodges <[email protected]>");
+MODULE_DESCRIPTION("BPF LED trigger");
+MODULE_LICENSE("GPL v2");
#3 lore raw

Re: [PATCH 1/3] leds: trigger: legtrig-bpf: Add ledtrig-bpf module

In reply to Daniel Hodges

Hi!

Quoted 8 lines

This patch adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity through calling bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point.

Signed-off-by Daniel Hodges <[email protected]>

drivers/leds/trigger/ledtrig-bpf.c line 43

Quoted 8 lines
drivers/leds/trigger/ledtrig-bpf.c new file +8 -0
+static int init_bpf(void)
+{
+	int ret;
+
+	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC,
+			&ledtrig_bpf_kfunc_set);
+	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING,
+			&ledtrig_bpf_kfunc_set);

Should have ret ?: here, too?

drivers/leds/trigger/ledtrig-bpf.c line 60

Quoted 6 lines
drivers/leds/trigger/ledtrig-bpf.c new file +6 -0
+static int ledtrig_bpf_init(void)
+{
+	led_trigger_register_simple("bpf", &ledtrig_bpf);
+
+	return init_bpf();
+}

Is it somehow possible to have multiple LEDs hooked to bpf functionality? I guess someone will want that...

Best regards,
Pavel

Signature · 1 line
People of Russia, stop Putin before his war on Ukraine escalates.
#4 lore raw

Re: [PATCH 1/3] leds: trigger: legtrig-bpf: Add ledtrig-bpf module

In reply to Daniel Hodges
Quoted 62 lines · Daniel Hodges

This patch adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity through calling bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point.

Signed-off-by Daniel Hodges <[email protected]>
---
 drivers/leds/trigger/Kconfig       | 10 +++++
 drivers/leds/trigger/Makefile      |  1 +
 drivers/leds/trigger/ledtrig-bpf.c | 72 ++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+)
 create mode 100644 drivers/leds/trigger/ledtrig-bpf.c
drivers/leds/trigger/Kconfig +10 -0
index d11d80176fc0..30b0fd3847be 100644
@@ -152,4 +152,14 @@ config LEDS_TRIGGER_TTY
 
          When build as a module this driver will be called ledtrig-tty.
 
+config LEDS_TRIGGER_BPF
+       tristate "LED BPF Trigger"
+       depends on BPF
+       depends on BPF_SYSCALL
+       help
+         This allows LEDs to be controlled by the BPF subsystem. This trigger
+         must be used with a loaded BPF program in order to control LED state.
+         BPF programs can control LED state with kfuncs.
+         If unsure, say N.
+
 endif # LEDS_TRIGGERS
drivers/leds/trigger/Makefile +1 -0
index 25c4db97cdd4..ac47128d406c 100644
@@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV)     += ledtrig-netdev.o
 obj-$(CONFIG_LEDS_TRIGGER_PATTERN)     += ledtrig-pattern.o
 obj-$(CONFIG_LEDS_TRIGGER_AUDIO)       += ledtrig-audio.o
 obj-$(CONFIG_LEDS_TRIGGER_TTY)         += ledtrig-tty.o
+obj-$(CONFIG_LEDS_TRIGGER_BPF)         += ledtrig-bpf.o
drivers/leds/trigger/ledtrig-bpf.c new file +13 -0
new file mode 100644
index 000000000000..e3b0b8281b70
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LED BPF Trigger
+ *
+ * Author: Daniel Hodges <[email protected]>
+ */
+
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/btf_ids.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>

drivers/leds/trigger/ledtrig-bpf.c line 23

Quoted 10 lines
drivers/leds/trigger/ledtrig-bpf.c new file +10 -0
+#include <linux/leds.h>
+
+
+DEFINE_LED_TRIGGER(ledtrig_bpf);
+
+__bpf_hook_start()
+
+__bpf_kfunc void bpf_ledtrig_blink(unsigned long delay_on, unsigned long delay_off, int invert)
+{
+       led_trigger_blink_oneshot(ledtrig_bpf, delay_on, delay_off, invert);

A new kernel module just to call this helper? Feels like overkill. Can it be a part of generic led bits? btw, have you looked at net/netfilter/xt_LED.c ? netfilter had the ability to blink led for a long time. I'm curious whether folks found it useful.
It can also do led_trigger_event().
Should that be another kfunc?

#5 lore raw

Re: [PATCH 1/3] leds: trigger: legtrig-bpf: Add ledtrig-bpf module

Quoted 5 lines

A new kernel module just to call this helper? Feels like overkill. Can it be a part of generic led bits? btw, have you looked at net/netfilter/xt_LED.c ? netfilter had the ability to blink led for a long time. I'm curious whether folks found it useful.

This might become more useful now that we have support for PHY & MAC LEDs. You can use the netdev trigger for the usual things an RJ45 LED
shows: link, rx/tx activity, link speed etc. But they are just Linux LEDs, you can also use them for heartbeat, disc IO, tty IO, or xt_LED. xt_LED would actually make sense for an LED in a RJ45 socket.

Andrew

#6 lore raw

Re: [PATCH 1/3] leds: trigger: legtrig-bpf: Add ledtrig-bpf module

In reply to Daniel Hodges
Quoted 5 lines · Daniel Hodges

This patch adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity through calling bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point.

Don't you want a mechanism to say which LED it should blink? Say you have a BPF IR receiver, a BPF kernel scheduler and a BPF firewall. All sharing the same LED is probably not what you want. Each probably wants its own LED.

Andrew

author
#7 lore raw

Re: [PATCH 1/3] leds: trigger: legtrig-bpf: Add ledtrig-bpf module

Quoted 8 lines · Daniel Hodges
Quoted 5 lines

This patch adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity through calling bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point.

Quoted 6 lines

Don't you want a mechanism to say which LED it should blink? Say you have a BPF IR receiver, a BPF kernel scheduler and a BPF firewall. All sharing the same LED is probably not what you want. Each probably wants its own LED.

Andrew

Yeah, I think that makes sense. I guess the idea with this patch set was more or less to show the simple implementation. Since there can be multiple devices the trigger probably needs a registry of the active led_classdev names or other id. Alexei mentioned the xt_led which looks like it is rather similar as well. I can give this another shot, but I didn't want to go too far down the rabbit hole without getting some signal on the idea in general.

PS Sorry to folks if I've directly replied to your comments. I'm still in the process of setting up my email workflow.

- Daniel

author
#8 lore raw

v2 cover leds: trigger: legtrig-bpf: Add ledtrig-bpf trigger

In reply to Daniel Hodges

This patch set adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity using bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point.

V1: https://lore.kernel.org/bpf/[email protected]/
Changes in V2:
- Change kfunc to trigger based on LED name.
- Fix kfunc registration of BPF_PROG_TYPE_UNSPEC.
- Use new kfunc helpers off bpf-next branch.

Daniel Hodges (3):
leds: trigger: legtrig-bpf: Add ledtrig-bpf trigger selftests/bpf: Add selftests for bpf led programs
leds: trigger: Add documentation for ledtrig-bpf

 Documentation/leds/index.rst                  |  1 +
 Documentation/leds/ledtrig-bpf.rst            | 13 ++++
 drivers/leds/trigger/Kconfig                  | 10 +++
 drivers/leds/trigger/Makefile                 |  1 +
 drivers/leds/trigger/ledtrig-bpf.c            | 73 +++++++++++++++++++
 tools/testing/selftests/bpf/config            |  1 +
 .../testing/selftests/bpf/progs/ledtrig_bpf.c | 32 ++++++++
 7 files changed, 131 insertions(+)
 create mode 100644 Documentation/leds/ledtrig-bpf.rst
 create mode 100644 drivers/leds/trigger/ledtrig-bpf.c
 create mode 100644 tools/testing/selftests/bpf/progs/ledtrig_bpf.c
Signature · 1 line
2.43.2
author
#9 lore raw

PATCH v2 1/3 leds: trigger: legtrig-bpf: Add ledtrig-bpf trigger

This patch adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity through calling bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point.

Signed-off-by Daniel Hodges <[email protected]>
---
 drivers/leds/trigger/Kconfig       | 10 ++++
 drivers/leds/trigger/Makefile      |  1 +
 drivers/leds/trigger/ledtrig-bpf.c | 73 ++++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+)
 create mode 100644 drivers/leds/trigger/ledtrig-bpf.c
drivers/leds/trigger/Kconfig +10 -0
index d11d80176fc0..30b0fd3847be 100644
@@ -152,4 +152,14 @@ config LEDS_TRIGGER_TTY
 
 	  When build as a module this driver will be called ledtrig-tty.
 
+config LEDS_TRIGGER_BPF
+	tristate "LED BPF Trigger"
+	depends on BPF
+	depends on BPF_SYSCALL
+	help
+	  This allows LEDs to be controlled by the BPF subsystem. This trigger
+	  must be used with a loaded BPF program in order to control LED state.
+	  BPF programs can control LED state with kfuncs.
+	  If unsure, say N.
+
 endif # LEDS_TRIGGERS
drivers/leds/trigger/Makefile +1 -0
index 25c4db97cdd4..ac47128d406c 100644
@@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
 obj-$(CONFIG_LEDS_TRIGGER_PATTERN)	+= ledtrig-pattern.o
 obj-$(CONFIG_LEDS_TRIGGER_AUDIO)	+= ledtrig-audio.o
 obj-$(CONFIG_LEDS_TRIGGER_TTY)		+= ledtrig-tty.o
+obj-$(CONFIG_LEDS_TRIGGER_BPF)		+= ledtrig-bpf.o
drivers/leds/trigger/ledtrig-bpf.c new file +73 -0

73 lines not on this page · raw message

Signature · 1 line
2.43.2
maintainer
#10 lore raw

Re: [PATCH v2 1/3] leds: trigger: legtrig-bpf: Add ledtrig-bpf trigger

Quoted 48 lines · Daniel Hodges

This patch adds a led trigger that interfaces with the bpf subsystem. It allows for BPF programs to control LED activity through calling bpf kfuncs. This functionality is useful in giving users a physical indication that a BPF program has performed an operation such as handling a packet or probe point.

Signed-off-by Daniel Hodges <[email protected]>
---
 drivers/leds/trigger/Kconfig       | 10 ++++
 drivers/leds/trigger/Makefile      |  1 +
 drivers/leds/trigger/ledtrig-bpf.c | 73 ++++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+)
 create mode 100644 drivers/leds/trigger/ledtrig-bpf.c
drivers/leds/trigger/Kconfig +10 -0
index d11d80176fc0..30b0fd3847be 100644
@@ -152,4 +152,14 @@ config LEDS_TRIGGER_TTY
 
 	  When build as a module this driver will be called ledtrig-tty.
 
+config LEDS_TRIGGER_BPF
+	tristate "LED BPF Trigger"
+	depends on BPF
+	depends on BPF_SYSCALL
+	help
+	  This allows LEDs to be controlled by the BPF subsystem. This trigger
+	  must be used with a loaded BPF program in order to control LED state.
+	  BPF programs can control LED state with kfuncs.
+	  If unsure, say N.
+
 endif # LEDS_TRIGGERS
drivers/leds/trigger/Makefile +1 -0
index 25c4db97cdd4..ac47128d406c 100644
@@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
 obj-$(CONFIG_LEDS_TRIGGER_PATTERN)	+= ledtrig-pattern.o
 obj-$(CONFIG_LEDS_TRIGGER_AUDIO)	+= ledtrig-audio.o
 obj-$(CONFIG_LEDS_TRIGGER_TTY)		+= ledtrig-tty.o
+obj-$(CONFIG_LEDS_TRIGGER_BPF)		+= ledtrig-bpf.o
drivers/leds/trigger/ledtrig-bpf.c new file +0 -0
new file mode 100644
index 000000000000..99cabf816da4

drivers/leds/trigger/ledtrig-bpf.c line 5

Quoted 5 lines
drivers/leds/trigger/ledtrig-bpf.c new file +5 -0
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LED BPF Trigger
+ *
+ * Author: Daniel Hodges <[email protected]>

Any copyright?

Quoted 5 lines
drivers/leds/trigger/ledtrig-bpf.c new file +5 -0
+ */
+
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/btf_ids.h>

drivers/leds/trigger/ledtrig-bpf.c line 20

Quoted 10 lines
drivers/leds/trigger/ledtrig-bpf.c new file +10 -0
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/rcupdate.h>
+
+
+DEFINE_LED_TRIGGER(ledtrig_bpf);
+
+__bpf_kfunc_start_defs();

__bpf_hook_start()?

drivers/leds/trigger/ledtrig-bpf.c line 22

Quoted 2 lines
drivers/leds/trigger/ledtrig-bpf.c new file +2 -0
+__bpf_kfunc void bpf_ledtrig_blink(const char *led_name__str, unsigned long
+		delay_on, unsigned long delay_off, int invert)

Nit: Try to keep the variable types and names together please.

I.e. break before the 'unsigned' or after 'delay_on'.

drivers/leds/trigger/ledtrig-bpf.c line 30

Quoted 8 lines
drivers/leds/trigger/ledtrig-bpf.c new file +8 -0
+{
+	struct led_classdev *led_cdev;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(led_cdev, &ledtrig_bpf->led_cdevs, trig_list) {
+		if (strcmp(led_name__str, led_cdev->name) == 0) {
+			led_blink_set_oneshot(led_cdev, &delay_on, &delay_off,
+					invert);

Use 100-chars to avoid the break.

drivers/leds/trigger/ledtrig-bpf.c line 36

Quoted 6 lines
drivers/leds/trigger/ledtrig-bpf.c new file +6 -0
+			break;
+		}
+	}
+	rcu_read_unlock();
+}
+__bpf_kfunc_end_defs();

_bpf_hook_end()?

drivers/leds/trigger/ledtrig-bpf.c line 40

Quoted 3 lines
drivers/leds/trigger/ledtrig-bpf.c new file +3 -0
+BTF_KFUNCS_START(ledtrig_bpf_kfunc_ids)
+BTF_ID_FLAGS(func, bpf_ledtrig_blink, KF_TRUSTED_ARGS)
+BTF_KFUNCS_END(ledtrig_bpf_kfunc_ids)

Why not a single macro to output the full struct?

Or better yet, be less opaque and not use a macro at all?

drivers/leds/trigger/ledtrig-bpf.c line 53

Quoted 12 lines
drivers/leds/trigger/ledtrig-bpf.c new file +12 -0
+static const struct btf_kfunc_id_set ledtrig_bpf_kfunc_set = {
+	.owner = THIS_MODULE,
+	.set   = &ledtrig_bpf_kfunc_ids,
+};
+
+static int init_bpf(void)
+{
+	int ret;
+
+	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC,
+			&ledtrig_bpf_kfunc_set);
+	return ret;

return register_btf_kfunc_id_set()?

Or again, better yet, put the single function call directly into ledtrig_bpf_init()? Creating a whole function just for a single invocation seems superfluous.

Quoted 23 lines
drivers/leds/trigger/ledtrig-bpf.c new file +20 -0
+}
+
+static int __init ledtrig_bpf_init(void)
+{
+	led_trigger_register_simple("bpf", &ledtrig_bpf);
+
+	return init_bpf();
+}
+
+static void __exit ledtrig_bpf_exit(void)
+{
+	led_trigger_unregister_simple(ledtrig_bpf);
+}
+
+module_init(ledtrig_bpf_init);
+module_exit(ledtrig_bpf_exit);
+
+MODULE_AUTHOR("Daniel Hodges <[email protected]>");
+MODULE_DESCRIPTION("BPF LED trigger");
+MODULE_LICENSE("GPL v2");
Signature · 1 line
2.43.2
Signature · 1 line
Lee Jones [李琼斯]
author
#11 lore raw

PATCH v2 2/3 selftests/bpf: Add selftests for bpf led programs

In reply to Daniel Hodges

Add selftests for led trigger bpf programs. To run the tests use the "test_progs -t ledtrig_bpf" helper.

Signed-off-by Daniel Hodges <[email protected]>
---
 tools/testing/selftests/bpf/config            |  1 +
 .../testing/selftests/bpf/progs/ledtrig_bpf.c | 32 +++++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/ledtrig_bpf.c
tools/testing/selftests/bpf/config +1 -0
index 01f241ea2c67..17a027905dcd 100644
@@ -42,6 +42,7 @@ CONFIG_IPV6_SEG6_BPF=y
 CONFIG_IPV6_SIT=y
 CONFIG_IPV6_TUNNEL=y
 CONFIG_KEYS=y
+CONFIG_LEDS_TRIGGER_BPF=y
 CONFIG_LIRC=y
 CONFIG_LWTUNNEL=y
 CONFIG_MODULE_SIG=y
tools/testing/selftests/bpf/progs/ledtrig_bpf.c new file +32 -0
new file mode 100644
index 000000000000..d2096f13e5b6
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <vmlinux.h>
+
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+
+
+extern void bpf_ledtrig_blink(const char *led_name, unsigned long delay_on,
+		unsigned long delay_off, int invert) __weak __ksym;
+
+
+SEC("perf_event")
+int perf_blink(void)
+{
+	const char *led = "test_led";
+
+	bpf_ledtrig_blink(led, 30, 30, 0);
+	return 0;
+}
+
+
+SEC("syscall")
+int fork_blink(void)
+{
+	const char *led = "test_led";
+
+	bpf_ledtrig_blink(led, 30, 30, 0);
+	return 0;
+}
+
+char LICENSE[] SEC("license") = "GPL";
Signature · 1 line
2.43.2
author
#12 lore raw

PATCH v2 3/3 leds: trigger: Add documentation for ledtrig-bpf

In reply to Daniel Hodges

Update the documentation for led triggers to include the BPF LED trigger.

Signed-off-by Daniel Hodges <[email protected]>
---
 Documentation/leds/index.rst       |  1 +
 Documentation/leds/ledtrig-bpf.rst | 13 +++++++++++++
 2 files changed, 14 insertions(+)
 create mode 100644 Documentation/leds/ledtrig-bpf.rst
Documentation/leds/index.rst +1 -0
index 3ade16c18328..2af52a19d6bb 100644
@@ -10,6 +10,7 @@ LEDs
    leds-class
    leds-class-flash
    leds-class-multicolor
+   ledtrig-bpf
    ledtrig-oneshot
    ledtrig-transient
    ledtrig-usbport
Documentation/leds/ledtrig-bpf.rst new file +13 -0
new file mode 100644
index 000000000000..391a305f69d1
@@ -0,0 +1,13 @@
+====================
+BPF LED Trigger
+====================
+
+This LED trigger is useful for triggering LEDs from the BPF subsystem.  This
+trigger is designed to be used in combination with a BPF program that interacts
+with the trigger via a kfunc.  The exported kfuncs will have BTF names that
+start with "bpf_ledtrig_".
+
+The trigger can be activated from user space on led class devices as shown
+below::
+
+  echo bpf > trigger
Signature · 1 line
2.43.2
maintainer
#13 lore raw

Re: [PATCH v2 3/3] leds: trigger: Add documentation for ledtrig-bpf

Quoted 1 line · Daniel Hodges

Update the documentation for led triggers to include the BPF LED

LED throughout please.

Same in the previous commit please.

Quoted 43 lines

trigger.

Signed-off-by Daniel Hodges <[email protected]>
---
 Documentation/leds/index.rst       |  1 +
 Documentation/leds/ledtrig-bpf.rst | 13 +++++++++++++
 2 files changed, 14 insertions(+)
 create mode 100644 Documentation/leds/ledtrig-bpf.rst
Documentation/leds/index.rst +1 -0
index 3ade16c18328..2af52a19d6bb 100644
@@ -10,6 +10,7 @@ LEDs
    leds-class
    leds-class-flash
    leds-class-multicolor
+   ledtrig-bpf
    ledtrig-oneshot
    ledtrig-transient
    ledtrig-usbport
Documentation/leds/ledtrig-bpf.rst new file +13 -0
new file mode 100644
index 000000000000..391a305f69d1
@@ -0,0 +1,13 @@
+====================
+BPF LED Trigger
+====================
+
+This LED trigger is useful for triggering LEDs from the BPF subsystem.  This
+trigger is designed to be used in combination with a BPF program that interacts
+with the trigger via a kfunc.  The exported kfuncs will have BTF names that
+start with "bpf_ledtrig_".
+
+The trigger can be activated from user space on led class devices as shown
+below::
+
+  echo bpf > trigger
Signature · 1 line
2.43.2
Signature · 1 line
Lee Jones [李琼斯]
author
#14 lore raw

PATCH 2/3 selftests/bpf: Add selftests for bpf led programs

In reply to Daniel Hodges

Add selftests for led trigger bpf programs. To run the tests use the "test_progs -t ledtrig_bpf" helper.

Signed-off-by Daniel Hodges <[email protected]>
---
 tools/testing/selftests/bpf/config            |  1 +
 .../testing/selftests/bpf/progs/ledtrig_bpf.c | 28 +++++++++++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/ledtrig_bpf.c
tools/testing/selftests/bpf/config +1 -0
index 01f241ea2c67..17a027905dcd 100644
@@ -42,6 +42,7 @@ CONFIG_IPV6_SEG6_BPF=y
 CONFIG_IPV6_SIT=y
 CONFIG_IPV6_TUNNEL=y
 CONFIG_KEYS=y
+CONFIG_LEDS_TRIGGER_BPF=y
 CONFIG_LIRC=y
 CONFIG_LWTUNNEL=y
 CONFIG_MODULE_SIG=y
tools/testing/selftests/bpf/progs/ledtrig_bpf.c new file +28 -0
new file mode 100644
index 000000000000..8bf1044e6896
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <vmlinux.h>
+
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+
+
+extern void bpf_ledtrig_blink(unsigned long delay_on, unsigned long delay_off,
+		int invert) __weak __ksym;
+
+
+SEC("perf_event")
+int perf_blink(void)
+{
+	bpf_ledtrig_blink(30, 30, 0);
+	return 0;
+}
+
+
+SEC("syscall")
+int fork_blink(void)
+{
+	bpf_ledtrig_blink(30, 30, 0);
+	return 0;
+}
+
+char LICENSE[] SEC("license") = "GPL";
Signature · 1 line
2.43.0
author
#15 lore raw

PATCH 3/3 leds: trigger: Add documentation for ledtrig-bpf

In reply to Daniel Hodges

Update the documentation for led triggers to include the BPF LED trigger.

Signed-off-by Daniel Hodges <[email protected]>
---
 Documentation/leds/index.rst       |  1 +
 Documentation/leds/ledtrig-bpf.rst | 13 +++++++++++++
 2 files changed, 14 insertions(+)
 create mode 100644 Documentation/leds/ledtrig-bpf.rst
Documentation/leds/index.rst +1 -0
index 3ade16c18328..2af52a19d6bb 100644
@@ -10,6 +10,7 @@ LEDs
    leds-class
    leds-class-flash
    leds-class-multicolor
+   ledtrig-bpf
    ledtrig-oneshot
    ledtrig-transient
    ledtrig-usbport
Documentation/leds/ledtrig-bpf.rst new file +13 -0
new file mode 100644
index 000000000000..391a305f69d1
@@ -0,0 +1,13 @@
+====================
+BPF LED Trigger
+====================
+
+This LED trigger is useful for triggering LEDs from the BPF subsystem.  This
+trigger is designed to be used in combination with a BPF program that interacts
+with the trigger via a kfunc.  The exported kfuncs will have BTF names that
+start with "bpf_ledtrig_".
+
+The trigger can be activated from user space on led class devices as shown
+below::
+
+  echo bpf > trigger
Signature · 1 line
2.43.0