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65f27f3844
Pass the work_struct pointer to the work function rather than context data. The work function can use container_of() to work out the data. For the cases where the container of the work_struct may go away the moment the pending bit is cleared, it is made possible to defer the release of the structure by deferring the clearing of the pending bit. To make this work, an extra flag is introduced into the management side of the work_struct. This governs auto-release of the structure upon execution. Ordinarily, the work queue executor would release the work_struct for further scheduling or deallocation by clearing the pending bit prior to jumping to the work function. This means that, unless the driver makes some guarantee itself that the work_struct won't go away, the work function may not access anything else in the work_struct or its container lest they be deallocated.. This is a problem if the auxiliary data is taken away (as done by the last patch). However, if the pending bit is *not* cleared before jumping to the work function, then the work function *may* access the work_struct and its container with no problems. But then the work function must itself release the work_struct by calling work_release(). In most cases, automatic release is fine, so this is the default. Special initiators exist for the non-auto-release case (ending in _NAR). Signed-Off-By: David Howells <dhowells@redhat.com>
45 lines
905 B
C
45 lines
905 B
C
/*
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* poweroff.c - sysrq handler to gracefully power down machine.
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*
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* This file is released under the GPL v2
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*/
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#include <linux/kernel.h>
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#include <linux/sysrq.h>
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#include <linux/init.h>
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#include <linux/pm.h>
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#include <linux/workqueue.h>
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#include <linux/reboot.h>
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/*
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* When the user hits Sys-Rq o to power down the machine this is the
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* callback we use.
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*/
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static void do_poweroff(struct work_struct *dummy)
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{
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kernel_power_off();
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}
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static DECLARE_WORK(poweroff_work, do_poweroff);
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static void handle_poweroff(int key, struct tty_struct *tty)
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{
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schedule_work(&poweroff_work);
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}
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static struct sysrq_key_op sysrq_poweroff_op = {
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.handler = handle_poweroff,
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.help_msg = "powerOff",
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.action_msg = "Power Off",
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.enable_mask = SYSRQ_ENABLE_BOOT,
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};
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static int pm_sysrq_init(void)
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{
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register_sysrq_key('o', &sysrq_poweroff_op);
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return 0;
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}
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subsys_initcall(pm_sysrq_init);
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