blk-mq: merge blk-softirq.c into blk-mq.c
authorChristoph Hellwig <hch@lst.de>
Thu, 11 Jun 2020 06:44:41 +0000 (08:44 +0200)
committerJens Axboe <axboe@kernel.dk>
Wed, 24 Jun 2020 15:15:56 +0000 (09:15 -0600)
__blk_complete_request is only called from the blk-mq code, and
duplicates a lot of code from blk-mq.c.  Move it there to prepare
for better code sharing and simplifications.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/Makefile
block/blk-mq.c
block/blk-softirq.c [deleted file]
include/linux/blkdev.h

index 7871916..8d841f5 100644 (file)
@@ -5,7 +5,7 @@
 
 obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-sysfs.o \
                        blk-flush.o blk-settings.o blk-ioc.o blk-map.o \
-                       blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \
+                       blk-exec.o blk-merge.o blk-timeout.o \
                        blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \
                        blk-mq-sysfs.o blk-mq-cpumap.o blk-mq-sched.o ioctl.o \
                        genhd.o ioprio.o badblocks.o partitions/ blk-rq-qos.o
index a9aa6d1..60febbf 100644 (file)
@@ -41,6 +41,8 @@
 #include "blk-mq-sched.h"
 #include "blk-rq-qos.h"
 
+static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
+
 static void blk_mq_poll_stats_start(struct request_queue *q);
 static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
 
@@ -574,6 +576,130 @@ void blk_mq_end_request(struct request *rq, blk_status_t error)
 }
 EXPORT_SYMBOL(blk_mq_end_request);
 
+/*
+ * Softirq action handler - move entries to local list and loop over them
+ * while passing them to the queue registered handler.
+ */
+static __latent_entropy void blk_done_softirq(struct softirq_action *h)
+{
+       struct list_head *cpu_list, local_list;
+
+       local_irq_disable();
+       cpu_list = this_cpu_ptr(&blk_cpu_done);
+       list_replace_init(cpu_list, &local_list);
+       local_irq_enable();
+
+       while (!list_empty(&local_list)) {
+               struct request *rq;
+
+               rq = list_entry(local_list.next, struct request, ipi_list);
+               list_del_init(&rq->ipi_list);
+               rq->q->mq_ops->complete(rq);
+       }
+}
+
+#ifdef CONFIG_SMP
+static void trigger_softirq(void *data)
+{
+       struct request *rq = data;
+       struct list_head *list;
+
+       list = this_cpu_ptr(&blk_cpu_done);
+       list_add_tail(&rq->ipi_list, list);
+
+       if (list->next == &rq->ipi_list)
+               raise_softirq_irqoff(BLOCK_SOFTIRQ);
+}
+
+/*
+ * Setup and invoke a run of 'trigger_softirq' on the given cpu.
+ */
+static int raise_blk_irq(int cpu, struct request *rq)
+{
+       if (cpu_online(cpu)) {
+               call_single_data_t *data = &rq->csd;
+
+               data->func = trigger_softirq;
+               data->info = rq;
+               data->flags = 0;
+
+               smp_call_function_single_async(cpu, data);
+               return 0;
+       }
+
+       return 1;
+}
+#else /* CONFIG_SMP */
+static int raise_blk_irq(int cpu, struct request *rq)
+{
+       return 1;
+}
+#endif
+
+static int blk_softirq_cpu_dead(unsigned int cpu)
+{
+       /*
+        * If a CPU goes away, splice its entries to the current CPU
+        * and trigger a run of the softirq
+        */
+       local_irq_disable();
+       list_splice_init(&per_cpu(blk_cpu_done, cpu),
+                        this_cpu_ptr(&blk_cpu_done));
+       raise_softirq_irqoff(BLOCK_SOFTIRQ);
+       local_irq_enable();
+
+       return 0;
+}
+
+static void __blk_complete_request(struct request *req)
+{
+       struct request_queue *q = req->q;
+       int cpu, ccpu = req->mq_ctx->cpu;
+       unsigned long flags;
+       bool shared = false;
+
+       BUG_ON(!q->mq_ops->complete);
+
+       local_irq_save(flags);
+       cpu = smp_processor_id();
+
+       /*
+        * Select completion CPU
+        */
+       if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) && ccpu != -1) {
+               if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags))
+                       shared = cpus_share_cache(cpu, ccpu);
+       } else
+               ccpu = cpu;
+
+       /*
+        * If current CPU and requested CPU share a cache, run the softirq on
+        * the 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 || shared) {
+               struct list_head *list;
+do_local:
+               list = this_cpu_ptr(&blk_cpu_done);
+               list_add_tail(&req->ipi_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->ipi_list)
+                       raise_softirq_irqoff(BLOCK_SOFTIRQ);
+       } else if (raise_blk_irq(ccpu, req))
+               goto do_local;
+
+       local_irq_restore(flags);
+}
+
 static void __blk_mq_complete_request_remote(void *data)
 {
        struct request *rq = data;
@@ -3760,6 +3886,15 @@ EXPORT_SYMBOL(blk_mq_rq_cpu);
 
 static int __init blk_mq_init(void)
 {
+       int i;
+
+       for_each_possible_cpu(i)
+               INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
+       open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
+
+       cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
+                                 "block/softirq:dead", NULL,
+                                 blk_softirq_cpu_dead);
        cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
                                blk_mq_hctx_notify_dead);
        cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online",
diff --git a/block/blk-softirq.c b/block/blk-softirq.c
deleted file mode 100644 (file)
index 6e7ec87..0000000
+++ /dev/null
@@ -1,156 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Functions related to softirq rq completions
- */
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/bio.h>
-#include <linux/blkdev.h>
-#include <linux/interrupt.h>
-#include <linux/cpu.h>
-#include <linux/sched.h>
-#include <linux/sched/topology.h>
-
-#include "blk.h"
-
-static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
-
-/*
- * Softirq action handler - move entries to local list and loop over them
- * while passing them to the queue registered handler.
- */
-static __latent_entropy void blk_done_softirq(struct softirq_action *h)
-{
-       struct list_head *cpu_list, local_list;
-
-       local_irq_disable();
-       cpu_list = this_cpu_ptr(&blk_cpu_done);
-       list_replace_init(cpu_list, &local_list);
-       local_irq_enable();
-
-       while (!list_empty(&local_list)) {
-               struct request *rq;
-
-               rq = list_entry(local_list.next, struct request, ipi_list);
-               list_del_init(&rq->ipi_list);
-               rq->q->mq_ops->complete(rq);
-       }
-}
-
-#ifdef CONFIG_SMP
-static void trigger_softirq(void *data)
-{
-       struct request *rq = data;
-       struct list_head *list;
-
-       list = this_cpu_ptr(&blk_cpu_done);
-       list_add_tail(&rq->ipi_list, list);
-
-       if (list->next == &rq->ipi_list)
-               raise_softirq_irqoff(BLOCK_SOFTIRQ);
-}
-
-/*
- * Setup and invoke a run of 'trigger_softirq' on the given cpu.
- */
-static int raise_blk_irq(int cpu, struct request *rq)
-{
-       if (cpu_online(cpu)) {
-               call_single_data_t *data = &rq->csd;
-
-               data->func = trigger_softirq;
-               data->info = rq;
-               data->flags = 0;
-
-               smp_call_function_single_async(cpu, data);
-               return 0;
-       }
-
-       return 1;
-}
-#else /* CONFIG_SMP */
-static int raise_blk_irq(int cpu, struct request *rq)
-{
-       return 1;
-}
-#endif
-
-static int blk_softirq_cpu_dead(unsigned int cpu)
-{
-       /*
-        * If a CPU goes away, splice its entries to the current CPU
-        * and trigger a run of the softirq
-        */
-       local_irq_disable();
-       list_splice_init(&per_cpu(blk_cpu_done, cpu),
-                        this_cpu_ptr(&blk_cpu_done));
-       raise_softirq_irqoff(BLOCK_SOFTIRQ);
-       local_irq_enable();
-
-       return 0;
-}
-
-void __blk_complete_request(struct request *req)
-{
-       struct request_queue *q = req->q;
-       int cpu, ccpu = req->mq_ctx->cpu;
-       unsigned long flags;
-       bool shared = false;
-
-       BUG_ON(!q->mq_ops->complete);
-
-       local_irq_save(flags);
-       cpu = smp_processor_id();
-
-       /*
-        * Select completion CPU
-        */
-       if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) && ccpu != -1) {
-               if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags))
-                       shared = cpus_share_cache(cpu, ccpu);
-       } else
-               ccpu = cpu;
-
-       /*
-        * If current CPU and requested CPU share a cache, run the softirq on
-        * the 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 || shared) {
-               struct list_head *list;
-do_local:
-               list = this_cpu_ptr(&blk_cpu_done);
-               list_add_tail(&req->ipi_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->ipi_list)
-                       raise_softirq_irqoff(BLOCK_SOFTIRQ);
-       } else if (raise_blk_irq(ccpu, req))
-               goto do_local;
-
-       local_irq_restore(flags);
-}
-
-static __init int blk_softirq_init(void)
-{
-       int i;
-
-       for_each_possible_cpu(i)
-               INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
-
-       open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
-       cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
-                                 "block/softirq:dead", NULL,
-                                 blk_softirq_cpu_dead);
-       return 0;
-}
-subsys_initcall(blk_softirq_init);
index 8fd9009..98712cf 100644 (file)
@@ -1078,7 +1078,6 @@ void blk_steal_bios(struct bio_list *list, struct request *rq);
 extern bool blk_update_request(struct request *rq, blk_status_t error,
                               unsigned int nr_bytes);
 
-extern void __blk_complete_request(struct request *);
 extern void blk_abort_request(struct request *);
 
 /*