relayfs: Convert to hotplug state machine (e6d4989a) · Commits · 戴 / test

include/linux/cpuhotplug.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -21,6 +21,7 @@ enum cpuhp_state {
		CPUHP_PROFILE_PREPARE,
		CPUHP_X2APIC_PREPARE,
		CPUHP_SMPCFD_PREPARE,
		CPUHP_RELAY_PREPARE,
		CPUHP_RCUTREE_PREP,
		CPUHP_NOTIFY_PREPARE,
		CPUHP_TIMERS_DEAD,

include/linux/relay.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -288,5 +288,11 @@ static inline void subbuf_start_reserve(struct rchan_buf *buf,
		*/
		extern const struct file_operations relay_file_operations;

		#ifdef CONFIG_RELAY
		int relay_prepare_cpu(unsigned int cpu);
		#else
		#define relay_prepare_cpu NULL
		#endif

		#endif /* _LINUX_RELAY_H */

kernel/cpu.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -23,6 +23,7 @@
		#include <linux/tick.h>
		#include <linux/irq.h>
		#include <linux/smpboot.h>
		#include <linux/relay.h>

		#include <trace/events/power.h>
		#define CREATE_TRACE_POINTS
		@@ -1272,6 +1273,11 @@ static struct cpuhp_step cpuhp_bp_states[] = {
		.startup.single = smpcfd_prepare_cpu,
		.teardown.single = smpcfd_dead_cpu,
		},
		[CPUHP_RELAY_PREPARE] = {
		.name = "relay:prepare",
		.startup.single = relay_prepare_cpu,
		.teardown.single = NULL,
		},
		[CPUHP_RCUTREE_PREP] = {
		.name = "RCU/tree:prepare",
		.startup.single = rcutree_prepare_cpu,

kernel/relay.c

+13 −45

Original line number	Diff line number	Diff line
		@@ -513,48 +513,25 @@ static void setup_callbacks(struct rchan *chan,
		chan->cb = cb;
		}

		/**
		* relay_hotcpu_callback - CPU hotplug callback
		* @nb: notifier block
		* @action: hotplug action to take
		* @hcpu: CPU number
		*
		* Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD)
		*/
		static int relay_hotcpu_callback(struct notifier_block *nb,
		unsigned long action,
		void *hcpu)
		int relay_prepare_cpu(unsigned int cpu)
		{
		unsigned int hotcpu = (unsigned long)hcpu;
		struct rchan *chan;
		struct rchan_buf *buf;

		switch(action) {
		case CPU_UP_PREPARE:
		case CPU_UP_PREPARE_FROZEN:
		mutex_lock(&relay_channels_mutex);
		list_for_each_entry(chan, &relay_channels, list) {
		if ((buf = *per_cpu_ptr(chan->buf, hotcpu)))
		if ((buf = *per_cpu_ptr(chan->buf, cpu)))
		continue;
		buf = relay_open_buf(chan, hotcpu);
		buf = relay_open_buf(chan, cpu);
		if (!buf) {
		printk(KERN_ERR
		"relay_hotcpu_callback: cpu %d buffer "
		"creation failed\n", hotcpu);
		pr_err("relay: cpu %d buffer creation failed\n", cpu);
		mutex_unlock(&relay_channels_mutex);
		return notifier_from_errno(-ENOMEM);
		return -ENOMEM;
		}
		*per_cpu_ptr(chan->buf, hotcpu) = buf;
		*per_cpu_ptr(chan->buf, cpu) = buf;
		}
		mutex_unlock(&relay_channels_mutex);
		break;
		case CPU_DEAD:
		case CPU_DEAD_FROZEN:
		/* No need to flush the cpu : will be flushed upon
		* final relay_flush() call. */
		break;
		}
		return NOTIFY_OK;
		return 0;
		}

		/**
		@@ -1387,12 +1364,3 @@ const struct file_operations relay_file_operations = {
		.splice_read = relay_file_splice_read,
		};
		EXPORT_SYMBOL_GPL(relay_file_operations);

		static __init int relay_init(void)
		{

		hotcpu_notifier(relay_hotcpu_callback, 0);
		return 0;
		}

		early_initcall(relay_init);

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