From: Dmitry Osipenko <dmitry.osipenko@collabora.com>
To: "Thierry Reding" <thierry.reding@gmail.com>,
"Jonathan Hunter" <jonathanh@nvidia.com>,
"Russell King" <linux@armlinux.org.uk>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Will Deacon" <will@kernel.org>, "Guo Ren" <guoren@kernel.org>,
"Geert Uytterhoeven" <geert@linux-m68k.org>,
"Greg Ungerer" <gerg@linux-m68k.org>,
"Joshua Thompson" <funaho@jurai.org>,
"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
"Sebastian Reichel" <sre@kernel.org>,
"Linus Walleij" <linus.walleij@linaro.org>,
"Philipp Zabel" <p.zabel@pengutronix.de>,
"Greentime Hu" <green.hu@gmail.com>,
"Vincent Chen" <deanbo422@gmail.com>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
"Helge Deller" <deller@gmx.de>,
"Michael Ellerman" <mpe@ellerman.id.au>,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
"Paul Mackerras" <paulus@samba.org>,
"Paul Walmsley" <paul.walmsley@sifive.com>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Albert Ou" <aou@eecs.berkeley.edu>,
"Yoshinori Sato" <ysato@users.sourceforge.jp>,
"Rich Felker" <dalias@libc.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Juergen Gross" <jgross@suse.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Len Brown" <lenb@kernel.org>,
"Santosh Shilimkar" <ssantosh@kernel.org>,
"Krzysztof Kozlowski" <krzk@kernel.org>,
"Liam Girdwood" <lgirdwood@gmail.com>,
"Mark Brown" <broonie@kernel.org>, "Pavel Machek" <pavel@ucw.cz>,
"Lee Jones" <lee.jones@linaro.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Guenter Roeck" <linux@roeck-us.net>,
"Daniel Lezcano" <daniel.lezcano@linaro.org>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Ulf Hansson" <ulf.hansson@linaro.org>,
"Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org,
xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org,
linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org
Subject: [PATCH v8 01/27] notifier: Add atomic_notifier_call_chain_is_empty()
Date: Tue, 10 May 2022 02:32:09 +0300 [thread overview]
Message-ID: <20220509233235.995021-2-dmitry.osipenko@collabora.com> (raw)
In-Reply-To: <20220509233235.995021-1-dmitry.osipenko@collabora.com>
Add atomic_notifier_call_chain_is_empty() that returns true if given
atomic call chain is empty.
Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
include/linux/notifier.h | 2 ++
kernel/notifier.c | 13 +++++++++++++
2 files changed, 15 insertions(+)
diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 87069b8459af..95e2440037de 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -173,6 +173,8 @@ extern int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh
extern int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
unsigned long val_up, unsigned long val_down, void *v);
+extern bool atomic_notifier_call_chain_is_empty(struct atomic_notifier_head *nh);
+
#define NOTIFY_DONE 0x0000 /* Don't care */
#define NOTIFY_OK 0x0001 /* Suits me */
#define NOTIFY_STOP_MASK 0x8000 /* Don't call further */
diff --git a/kernel/notifier.c b/kernel/notifier.c
index ba005ebf4730..aaf5b56452a6 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -204,6 +204,19 @@ int atomic_notifier_call_chain(struct atomic_notifier_head *nh,
EXPORT_SYMBOL_GPL(atomic_notifier_call_chain);
NOKPROBE_SYMBOL(atomic_notifier_call_chain);
+/**
+ * atomicnotifier_call_chain_is_empty - Check whether notifier chain is empty
+ * @nh: Pointer to head of the blocking notifier chain
+ *
+ * Checks whether notifier chain is empty.
+ *
+ * Returns true is notifier chain is empty, false otherwise.
+ */
+bool atomic_notifier_call_chain_is_empty(struct atomic_notifier_head *nh)
+{
+ return !rcu_access_pointer(nh->head);
+}
+
/*
* Blocking notifier chain routines. All access to the chain is
* synchronized by an rwsem.
--
2.35.1
next prev parent reply other threads:[~2022-05-09 23:33 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-09 23:32 [PATCH v8 00/27] Introduce power-off+restart call chain API Dmitry Osipenko
2022-05-09 23:32 ` Dmitry Osipenko [this message]
2022-05-10 18:14 ` [PATCH v8 01/27] notifier: Add atomic_notifier_call_chain_is_empty() Rafael J. Wysocki
2022-05-11 10:12 ` Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 02/27] notifier: Add blocking/atomic_notifier_chain_register_unique_prio() Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 03/27] kernel/reboot: Introduce sys-off handler API Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 04/27] kernel/reboot: Wrap legacy power-off callbacks into sys-off handlers Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 05/27] kernel/reboot: Add do_kernel_power_off() Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 06/27] kernel/reboot: Add stub for pm_power_off Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 07/27] kernel/reboot: Add kernel_can_power_off() Dmitry Osipenko
2022-05-24 13:14 ` Geert Uytterhoeven
2022-05-24 13:41 ` Dmitry Osipenko
2022-05-24 15:03 ` Geert Uytterhoeven
2022-05-24 20:16 ` Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 08/27] kernel/reboot: Add register_platform_power_off() Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 09/27] ARM: Use do_kernel_power_off() Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 10/27] csky: " Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 11/27] riscv: " Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 12/27] arm64: " Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 13/27] parisc: " Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 14/27] xen/x86: " Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 15/27] powerpc: " Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 16/27] m68k: Switch to new sys-off handler API Dmitry Osipenko
2022-05-31 19:04 ` Geert Uytterhoeven
2022-05-31 21:24 ` Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 17/27] sh: Use do_kernel_power_off() Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 18/27] x86: " Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 19/27] ia64: " Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 20/27] mips: " Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 21/27] memory: emif: Use kernel_can_power_off() Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 22/27] ACPI: power: Switch to sys-off handler API Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 23/27] regulator: pfuze100: Use devm_register_sys_off_handler() Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 24/27] reboot: Remove pm_power_off_prepare() Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 25/27] soc/tegra: pmc: Use sys-off handler API to power off Nexus 7 properly Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 26/27] kernel/reboot: Add devm_register_power_off_handler() Dmitry Osipenko
2022-05-09 23:32 ` [PATCH v8 27/27] kernel/reboot: Add devm_register_restart_handler() Dmitry Osipenko
2022-05-18 14:46 ` [PATCH v8 00/27] Introduce power-off+restart call chain API Rafael J. Wysocki
2022-05-19 10:57 ` Dmitry Osipenko
2022-05-23 18:00 ` Geert Uytterhoeven
2022-05-24 13:43 ` Rafael J. Wysocki
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