From: Dmitry Osipenko <digetx@gmail.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>,
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Geert Uytterhoeven <geert@linux-m68k.org>,
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Joshua Thompson <funaho@jurai.org>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Sebastian Reichel <sre@kernel.org>,
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x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
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Stefano Stabellini <sstabellini@kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
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Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Ulf Hansson <ulf.hansson@linaro.org>,
alankao@andestech.com,
"K . C . Kuen-Chern Lin" <kclin@andestech.com>
Cc: linux-arm-kernel@lists.infradead.org,
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,
linuxppc-dev@lists.ozlabs.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 v4 03/25] notifier: Add atomic/blocking_notifier_has_unique_priority()
Date: Fri, 26 Nov 2021 21:00:39 +0300 [thread overview]
Message-ID: <20211126180101.27818-4-digetx@gmail.com> (raw)
In-Reply-To: <20211126180101.27818-1-digetx@gmail.com>
Add atomic/blocking_notifier_has_unique_priority() helpers which return
true if given handler has unique priority.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
include/linux/notifier.h | 5 +++
kernel/notifier.c | 69 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 74 insertions(+)
diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 924c9d7c8e73..2c4036f225e1 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -175,6 +175,11 @@ int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh);
+bool atomic_notifier_has_unique_priority(struct atomic_notifier_head *nh,
+ struct notifier_block *nb);
+bool blocking_notifier_has_unique_priority(struct blocking_notifier_head *nh,
+ struct notifier_block *nb);
+
#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 b20cb7b9b1f0..7a325b742104 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -122,6 +122,19 @@ static int notifier_call_chain_robust(struct notifier_block **nl,
return ret;
}
+static int notifier_has_unique_priority(struct notifier_block **nl,
+ struct notifier_block *n)
+{
+ while (*nl && (*nl)->priority >= n->priority) {
+ if ((*nl)->priority == n->priority && *nl != n)
+ return false;
+
+ nl = &((*nl)->next);
+ }
+
+ return true;
+}
+
/*
* Atomic notifier chain routines. Registration and unregistration
* use a spinlock, and call_chain is synchronized by RCU (no locks).
@@ -203,6 +216,30 @@ int atomic_notifier_call_chain(struct atomic_notifier_head *nh,
EXPORT_SYMBOL_GPL(atomic_notifier_call_chain);
NOKPROBE_SYMBOL(atomic_notifier_call_chain);
+/**
+ * atomic_notifier_has_unique_priority - Checks whether notifier's priority is unique
+ * @nh: Pointer to head of the atomic notifier chain
+ * @n: Entry in notifier chain to check
+ *
+ * Checks whether there is another notifier in the chain with the same priority.
+ * Must be called in process context.
+ *
+ * Returns true if priority is unique, false otherwise.
+ */
+bool atomic_notifier_has_unique_priority(struct atomic_notifier_head *nh,
+ struct notifier_block *n)
+{
+ unsigned long flags;
+ bool ret;
+
+ spin_lock_irqsave(&nh->lock, flags);
+ ret = notifier_has_unique_priority(&nh->head, n);
+ spin_unlock_irqrestore(&nh->lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_has_unique_priority);
+
/*
* Blocking notifier chain routines. All access to the chain is
* synchronized by an rwsem.
@@ -336,6 +373,38 @@ bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh)
}
EXPORT_SYMBOL_GPL(blocking_notifier_call_chain_is_empty);
+/**
+ * blocking_notifier_has_unique_priority - Checks whether notifier's priority is unique
+ * @nh: Pointer to head of the blocking notifier chain
+ * @n: Entry in notifier chain to check
+ *
+ * Checks whether there is another notifier in the chain with the same priority.
+ * Must be called in process context.
+ *
+ * Returns true if priority is unique, false otherwise.
+ */
+bool blocking_notifier_has_unique_priority(struct blocking_notifier_head *nh,
+ struct notifier_block *n)
+{
+ bool ret;
+
+ /*
+ * This code gets used during boot-up, when task switching is
+ * not yet working and interrupts must remain disabled. At such
+ * times we must not call down_read().
+ */
+ if (system_state != SYSTEM_BOOTING)
+ down_read(&nh->rwsem);
+
+ ret = notifier_has_unique_priority(&nh->head, n);
+
+ if (system_state != SYSTEM_BOOTING)
+ up_read(&nh->rwsem);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_has_unique_priority);
+
/*
* Raw notifier chain routines. There is no protection;
* the caller must provide it. Use at your own risk!
--
2.33.1
next prev parent reply other threads:[~2021-11-26 18:22 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-26 18:00 [PATCH v4 00/25] Introduce power-off+restart call chain API Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 01/25] notifier: Remove extern annotation from function prototypes Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 02/25] notifier: Add blocking_notifier_call_chain_is_empty() Dmitry Osipenko
2021-12-10 18:14 ` Rafael J. Wysocki
2021-12-10 18:19 ` Dmitry Osipenko
2021-11-26 18:00 ` Dmitry Osipenko [this message]
2021-12-10 18:19 ` [PATCH v4 03/25] notifier: Add atomic/blocking_notifier_has_unique_priority() Rafael J. Wysocki
2021-12-10 18:52 ` Dmitry Osipenko
2021-12-10 19:05 ` Rafael J. Wysocki
2021-12-10 19:33 ` Dmitry Osipenko
2021-12-10 20:16 ` Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 04/25] reboot: Correct typo in a comment Dmitry Osipenko
2021-12-10 18:21 ` Rafael J. Wysocki
2021-11-26 18:00 ` [PATCH v4 05/25] reboot: Warn if restart handler has duplicated priority Dmitry Osipenko
2021-11-28 0:28 ` Michał Mirosław
2021-11-28 21:06 ` Dmitry Osipenko
2021-11-29 0:26 ` Michał Mirosław
2021-11-29 11:34 ` Dmitry Osipenko
2021-12-10 18:27 ` Rafael J. Wysocki
2021-12-10 19:04 ` Dmitry Osipenko
2021-12-10 19:14 ` Rafael J. Wysocki
2021-12-10 19:42 ` Dmitry Osipenko
2021-12-10 19:44 ` Dmitry Osipenko
2021-12-10 19:49 ` Dmitry Osipenko
2021-12-13 9:23 ` Geert Uytterhoeven
2021-11-26 18:00 ` [PATCH v4 06/25] reboot: Warn if unregister_restart_handler() fails Dmitry Osipenko
2021-12-10 18:32 ` Rafael J. Wysocki
2021-12-10 18:54 ` Dmitry Osipenko
2021-12-10 19:08 ` Rafael J. Wysocki
2021-12-10 19:38 ` Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 07/25] reboot: Remove extern annotation from function prototypes Dmitry Osipenko
2021-12-10 18:09 ` Rafael J. Wysocki
2021-12-10 18:15 ` Dmitry Osipenko
2021-12-10 18:35 ` Rafael J. Wysocki
2021-12-10 18:56 ` Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 08/25] kernel: Add combined power-off+restart handler call chain API Dmitry Osipenko
2021-11-28 0:43 ` Michał Mirosław
2021-11-28 21:04 ` Dmitry Osipenko
2021-11-28 21:17 ` Michał Mirosław
2021-11-28 21:53 ` Dmitry Osipenko
2021-11-29 0:36 ` Michał Mirosław
2021-11-29 11:52 ` Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 09/25] ARM: Use do_kernel_power_off() Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 10/25] csky: " Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 11/25] riscv: " Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 12/25] arm64: " Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 13/25] parisc: " Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 14/25] xen/x86: " Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 15/25] powerpc: " Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 16/25] m68k: Switch to new sys-off handler API Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 17/25] sh: Use do_kernel_power_off() Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 18/25] x86: " Dmitry Osipenko
2021-11-28 1:15 ` Michał Mirosław
2021-11-28 21:06 ` Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 19/25] ia64: " Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 20/25] mips: " Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 21/25] nds32: " Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 22/25] memory: emif: Use kernel_can_power_off() Dmitry Osipenko
2021-11-28 1:23 ` Michał Mirosław
2021-11-28 21:04 ` Dmitry Osipenko
2021-11-26 18:00 ` [PATCH v4 23/25] ACPI: power: Switch to sys-off handler API Dmitry Osipenko
2021-11-26 18:01 ` [PATCH v4 24/25] regulator: pfuze100: Use devm_register_sys_off_handler() Dmitry Osipenko
2021-11-26 18:01 ` [PATCH v4 25/25] reboot: Remove pm_power_off_prepare() Dmitry Osipenko
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