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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/stop_machine.h
downloadlinux-linaro-stable-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'include/linux/stop_machine.h')
-rw-r--r--include/linux/stop_machine.h52
1 files changed, 52 insertions, 0 deletions
diff --git a/include/linux/stop_machine.h b/include/linux/stop_machine.h
new file mode 100644
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--- /dev/null
+++ b/include/linux/stop_machine.h
@@ -0,0 +1,52 @@
+#ifndef _LINUX_STOP_MACHINE
+#define _LINUX_STOP_MACHINE
+/* "Bogolock": stop the entire machine, disable interrupts. This is a
+ very heavy lock, which is equivalent to grabbing every spinlock
+ (and more). So the "read" side to such a lock is anything which
+ diables preeempt. */
+#include <linux/config.h>
+#include <linux/cpu.h>
+#include <asm/system.h>
+
+#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
+/**
+ * stop_machine_run: freeze the machine on all CPUs and run this function
+ * @fn: the function to run
+ * @data: the data ptr for the @fn()
+ * @cpu: the cpu to run @fn() on (or any, if @cpu == NR_CPUS.
+ *
+ * Description: This causes a thread to be scheduled on every other cpu,
+ * each of which disables interrupts, and finally interrupts are disabled
+ * on the current CPU. The result is that noone is holding a spinlock
+ * or inside any other preempt-disabled region when @fn() runs.
+ *
+ * This can be thought of as a very heavy write lock, equivalent to
+ * grabbing every spinlock in the kernel. */
+int stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu);
+
+/**
+ * __stop_machine_run: freeze the machine on all CPUs and run this function
+ * @fn: the function to run
+ * @data: the data ptr for the @fn
+ * @cpu: the cpu to run @fn on (or any, if @cpu == NR_CPUS.
+ *
+ * Description: This is a special version of the above, which returns the
+ * thread which has run @fn(): kthread_stop will return the return value
+ * of @fn(). Used by hotplug cpu.
+ */
+struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
+ unsigned int cpu);
+
+#else
+
+static inline int stop_machine_run(int (*fn)(void *), void *data,
+ unsigned int cpu)
+{
+ int ret;
+ local_irq_disable();
+ ret = fn(data);
+ local_irq_enable();
+ return ret;
+}
+#endif /* CONFIG_SMP */
+#endif /* _LINUX_STOP_MACHINE */