void __blk_complete_request(struct request *req)
{
int ccpu, cpu, group_cpu = NR_CPUS;
struct request_queue *q = req->q;
unsigned long flags;
BUG_ON(!q->softirq_done_fn);
local_irq_save(flags);
cpu = smp_processor_id();
/*
* Select completion CPU
*/
if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) && req->cpu != -1) {
ccpu = req->cpu;
if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) {
ccpu = blk_cpu_to_group(ccpu);
group_cpu = blk_cpu_to_group(cpu);
}
} else
ccpu = cpu;
/*
* If current CPU and requested CPU are in the same group, running
* softirq in current CPU. One might concern this is just like
* QUEUE_FLAG_SAME_FORCE, but actually not. blk_complete_request() is
* running in interrupt handler, and currently I/O controller doesn't
* support multiple interrupts, so current CPU is unique actually. This
* avoids IPI sending from current CPU to the first CPU of a group.
*/
if (ccpu == cpu || ccpu == group_cpu) {
struct list_head *list;
do_local:
list = &__get_cpu_var(blk_cpu_done);
list_add_tail(&req->csd.list, list);
/*
* if the list only contains our just added request,
* signal a raise of the softirq. If there are already
* entries there, someone already raised the irq but it
* hasn't run yet.
*/
if (list->next == &req->csd.list)
raise_softirq_irqoff(BLOCK_SOFTIRQ);
} else if (raise_blk_irq(ccpu, req))
goto do_local;
local_irq_restore(flags);
}
void __blk_complete_request(struct request *req)
{
int ccpu, cpu, group_cpu = NR_CPUS;
struct request_queue *q = req->q;
unsigned long flags;
BUG_ON(!q->softirq_done_fn);
local_irq_save(flags);
cpu = smp_processor_id();
/*
* Select completion CPU
*/
if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) && req->cpu != -1) {
ccpu = req->cpu;
if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) {
ccpu = blk_cpu_to_group(ccpu);
group_cpu = blk_cpu_to_group(cpu);
}
} else
ccpu = cpu;
if (ccpu == cpu || ccpu == group_cpu) {
struct list_head *list;
do_local:
list = &__get_cpu_var(blk_cpu_done);
list_add_tail(&req->csd.list, list);
/*
* if the list only contains our just added request,
* signal a raise of the softirq. If there are already
* entries there, someone already raised the irq but it
* hasn't run yet.
*/
if (list->next == &req->csd.list)
raise_softirq_irqoff(BLOCK_SOFTIRQ);
} else if (raise_blk_irq(ccpu, req))
goto do_local;
local_irq_restore(flags);
}
void __blk_complete_request(struct request *req)
{
struct request_queue *q = req->q;
unsigned long flags;
int ccpu, cpu, group_cpu;
BUG_ON(!q->softirq_done_fn);
/* 计算接收到中断的CPU */
local_irq_save(flags);
cpu = smp_processor_id();
group_cpu = blk_cpu_to_group(cpu);
/*
* Select completion CPU, 找到应该处理完成请求的CPU
*/ /* QUEUE_FLAG_SAME_COMP要求提交请求的CPU来做请求完成处理 */
if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) && req->cpu != -1)
ccpu = req->cpu;
else
ccpu = cpu;
if (ccpu == cpu || ccpu == group_cpu) { /* 处理完成请求的CPU和接收请求的CPU是同一个 */
struct list_head *list;
do_local:
list = &__get_cpu_var(blk_cpu_done);
list_add_tail(&req->csd.list, list); /* 将完成请求插入CPU的队列 */
/*
* if the list only contains our just added request,
* signal a raise of the softirq. If there are already
* entries there, someone already raised the irq but it
* hasn't run yet.
*/
if (list->next == &req->csd.list)
raise_softirq_irqoff(BLOCK_SOFTIRQ);
} else if (raise_blk_irq(ccpu, req)) /* 路由中断，路由成功返回0 */
goto do_local;
local_irq_restore(flags);
}
