104 lines
2.5 KiB
C
104 lines
2.5 KiB
C
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/*
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* Functions related to softirq rq completions
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/interrupt.h>
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#include <linux/cpu.h>
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#include "blk.h"
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static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
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static int __cpuinit blk_cpu_notify(struct notifier_block *self,
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unsigned long action, void *hcpu)
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{
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/*
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* If a CPU goes away, splice its entries to the current CPU
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* and trigger a run of the softirq
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*/
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if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
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int cpu = (unsigned long) hcpu;
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local_irq_disable();
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list_splice_init(&per_cpu(blk_cpu_done, cpu),
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&__get_cpu_var(blk_cpu_done));
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raise_softirq_irqoff(BLOCK_SOFTIRQ);
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local_irq_enable();
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}
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return NOTIFY_OK;
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}
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static struct notifier_block blk_cpu_notifier __cpuinitdata = {
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.notifier_call = blk_cpu_notify,
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};
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/*
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* splice the completion data to a local structure and hand off to
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* process_completion_queue() to complete the requests
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*/
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static void blk_done_softirq(struct softirq_action *h)
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{
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struct list_head *cpu_list, local_list;
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local_irq_disable();
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cpu_list = &__get_cpu_var(blk_cpu_done);
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list_replace_init(cpu_list, &local_list);
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local_irq_enable();
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while (!list_empty(&local_list)) {
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struct request *rq;
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rq = list_entry(local_list.next, struct request, donelist);
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list_del_init(&rq->donelist);
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rq->q->softirq_done_fn(rq);
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}
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}
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/**
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* blk_complete_request - end I/O on a request
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* @req: the request being processed
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*
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* Description:
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* Ends all I/O on a request. It does not handle partial completions,
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* unless the driver actually implements this in its completion callback
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* through requeueing. The actual completion happens out-of-order,
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* through a softirq handler. The user must have registered a completion
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* callback through blk_queue_softirq_done().
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**/
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void blk_complete_request(struct request *req)
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{
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struct list_head *cpu_list;
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unsigned long flags;
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BUG_ON(!req->q->softirq_done_fn);
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local_irq_save(flags);
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cpu_list = &__get_cpu_var(blk_cpu_done);
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list_add_tail(&req->donelist, cpu_list);
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raise_softirq_irqoff(BLOCK_SOFTIRQ);
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local_irq_restore(flags);
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}
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EXPORT_SYMBOL(blk_complete_request);
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int __init blk_softirq_init(void)
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{
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int i;
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for_each_possible_cpu(i)
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INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
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open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
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register_hotcpu_notifier(&blk_cpu_notifier);
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return 0;
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}
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subsys_initcall(blk_softirq_init);
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