null_blk: use blk_complete_request and blk_mq_complete_request

Use the block layer helpers for CPU-local completions instead of
reimplementing them locally.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index cc801cd..091b9ea 100644 (file)
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -60,7 +60,9 @@ enum {
        NULL_IRQ_NONE           = 0,
        NULL_IRQ_SOFTIRQ        = 1,
        NULL_IRQ_TIMER          = 2,
+};
 
+enum {
        NULL_Q_BIO              = 0,
        NULL_Q_RQ               = 1,
        NULL_Q_MQ               = 2,
@@ -172,18 +174,20 @@ static struct nullb_cmd *alloc_cmd(struct nullb_queue *nq, int can_wait)
 
 static void end_cmd(struct nullb_cmd *cmd)
 {
-       if (cmd->rq) {
-               if (queue_mode == NULL_Q_MQ)
-                       blk_mq_end_io(cmd->rq, 0);
-               else {
-                       INIT_LIST_HEAD(&cmd->rq->queuelist);
-                       blk_end_request_all(cmd->rq, 0);
-               }
-       } else if (cmd->bio)
+       switch (queue_mode)  {
+       case NULL_Q_MQ:
+               blk_mq_end_io(cmd->rq, 0);
+               return;
+       case NULL_Q_RQ:
+               INIT_LIST_HEAD(&cmd->rq->queuelist);
+               blk_end_request_all(cmd->rq, 0);
+               break;
+       case NULL_Q_BIO:
                bio_endio(cmd->bio, 0);
+               break;
+       }
 
-       if (queue_mode != NULL_Q_MQ)
-               free_cmd(cmd);
+       free_cmd(cmd);
 }
 
 static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
@@ -222,62 +226,31 @@ static void null_cmd_end_timer(struct nullb_cmd *cmd)
 
 static void null_softirq_done_fn(struct request *rq)
 {
-       blk_end_request_all(rq, 0);
-}
-
-#ifdef CONFIG_SMP
-
-static void null_ipi_cmd_end_io(void *data)
-{
-       struct completion_queue *cq;
-       struct llist_node *entry, *next;
-       struct nullb_cmd *cmd;
-
-       cq = &per_cpu(completion_queues, smp_processor_id());
-
-       entry = llist_del_all(&cq->list);
-       entry = llist_reverse_order(entry);
-
-       while (entry) {
-               next = entry->next;
-               cmd = llist_entry(entry, struct nullb_cmd, ll_list);
-               end_cmd(cmd);
-               entry = next;
-       }
-}
-
-static void null_cmd_end_ipi(struct nullb_cmd *cmd)
-{
-       struct call_single_data *data = &cmd->csd;
-       int cpu = get_cpu();
-       struct completion_queue *cq = &per_cpu(completion_queues, cpu);
-
-       cmd->ll_list.next = NULL;
-
-       if (llist_add(&cmd->ll_list, &cq->list)) {
-               data->func = null_ipi_cmd_end_io;
-               data->flags = 0;
-               __smp_call_function_single(cpu, data, 0);
-       }
-
-       put_cpu();
+       end_cmd(rq->special);
 }
 
-#endif /* CONFIG_SMP */
-
 static inline void null_handle_cmd(struct nullb_cmd *cmd)
 {
        /* Complete IO by inline, softirq or timer */
        switch (irqmode) {
-       case NULL_IRQ_NONE:
-               end_cmd(cmd);
-               break;
        case NULL_IRQ_SOFTIRQ:
-#ifdef CONFIG_SMP
-               null_cmd_end_ipi(cmd);
-#else
+               switch (queue_mode)  {
+               case NULL_Q_MQ:
+                       blk_mq_complete_request(cmd->rq);
+                       break;
+               case NULL_Q_RQ:
+                       blk_complete_request(cmd->rq);
+                       break;
+               case NULL_Q_BIO:
+                       /*
+                        * XXX: no proper submitting cpu information available.
+                        */
+                       end_cmd(cmd);
+                       break;
+               }
+               break;
+       case NULL_IRQ_NONE:
                end_cmd(cmd);
-#endif
                break;
        case NULL_IRQ_TIMER:
                null_cmd_end_timer(cmd);
@@ -413,6 +386,7 @@ static struct blk_mq_ops null_mq_ops = {
        .queue_rq       = null_queue_rq,
        .map_queue      = blk_mq_map_queue,
        .init_hctx      = null_init_hctx,
+       .complete       = null_softirq_done_fn,
 };
 
 static struct blk_mq_reg null_mq_reg = {
@@ -611,13 +585,6 @@ static int __init null_init(void)
 {
        unsigned int i;
 
-#if !defined(CONFIG_SMP)
-       if (irqmode == NULL_IRQ_SOFTIRQ) {
-               pr_warn("null_blk: softirq completions not available.\n");
-               pr_warn("null_blk: using direct completions.\n");
-               irqmode = NULL_IRQ_NONE;
-       }
-#endif
        if (bs > PAGE_SIZE) {
                pr_warn("null_blk: invalid block size\n");
                pr_warn("null_blk: defaults block size to %lu\n", PAGE_SIZE);