#include <linux/kernel.h> #include <linux/module.h> #include <linux/backing-dev.h> #include <linux/bio.h> #include <linux/blkdev.h> #include <linux/mm.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/workqueue.h> #include <linux/smp.h> #include <linux/llist.h> #include <linux/list_sort.h> #include <linux/cpu.h> #include <linux/cache.h> #include <linux/sched/sysctl.h> #include <linux/delay.h> #include <trace/events/block.h> #include <linux/blk-mq.h> #include "blk.h" #include "blk-mq.h" #include "blk-mq-tag.h" static DEFINE_MUTEX(all_q_mutex); static LIST_HEAD(all_q_list); static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx); DEFINE_PER_CPU(struct llist_head, ipi_lists); static struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q, unsigned int cpu) { return per_cpu_ptr(q->queue_ctx, cpu); } /* * This assumes per-cpu software queueing queues. They could be per-node * as well, for instance. For now this is hardcoded as-is. Note that we don't * care about preemption, since we know the ctx's are persistent. This does * mean that we can't rely on ctx always matching the currently running CPU. */ static struct blk_mq_ctx *blk_mq_get_ctx(struct request_queue *q) { return __blk_mq_get_ctx(q, get_cpu()); } static void blk_mq_put_ctx(struct blk_mq_ctx *ctx) { put_cpu(); } /* * Check if any of the ctx's have pending work in this hardware queue */ static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) { unsigned int i; for (i = 0; i < hctx->nr_ctx_map; i++) if (hctx->ctx_map[i]) return true; return false; } /* * Mark this ctx as having pending work in this hardware queue */ static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx) { if (!test_bit(ctx->index_hw, hctx->ctx_map)) set_bit(ctx->index_hw, hctx->ctx_map); } static struct request *blk_mq_alloc_rq(struct blk_mq_hw_ctx *hctx, gfp_t gfp, bool reserved) { struct request *rq; unsigned int tag; tag = blk_mq_get_tag(hctx->tags, gfp, reserved); if (tag != BLK_MQ_TAG_FAIL) { rq = hctx->rqs[tag]; rq->tag = tag; return rq; } return NULL; } static int blk_mq_queue_enter(struct request_queue *q) { int ret; __percpu_counter_add(&q->mq_usage_counter, 1, 1000000); smp_wmb(); /* we have problems to freeze the queue if it's initializing */ if (!blk_queue_bypass(q) || !blk_queue_init_done(q)) return 0; __percpu_counter_add(&q->mq_usage_counter, -1, 1000000); spin_lock_irq(q->queue_lock); ret = wait_event_interruptible_lock_irq(q->mq_freeze_wq, !blk_queue_bypass(q), *q->queue_lock); /* inc usage with lock hold to avoid freeze_queue runs here */ if (!ret) __percpu_counter_add(&q->mq_usage_counter, 1, 1000000); spin_unlock_irq(q->queue_lock); return ret; } static void blk_mq_queue_exit(struct request_queue *q) { __percpu_counter_add(&q->mq_usage_counter, -1, 1000000); } /* * Guarantee no request is in use, so we can change any data structure of * the queue afterward. */ static void blk_mq_freeze_queue(struct request_queue *q) { bool drain; spin_lock_irq(q->queue_lock); drain = !q->bypass_depth++; queue_flag_set(QUEUE_FLAG_BYPASS, q); spin_unlock_irq(q->queue_lock); if (!drain) return; while (true) { s64 count; spin_lock_irq(q->queue_lock); count = percpu_counter_sum(&q->mq_usage_counter); spin_unlock_irq(q->queue_lock); if (count == 0) break; blk_mq_run_queues(q, false); msleep(10); } } static void blk_mq_unfreeze_queue(struct request_queue *q) { bool wake = false; spin_lock_irq(q->queue_lock); if (!--q->bypass_depth) { queue_flag_clear(QUEUE_FLAG_BYPASS, q); wake = true; } WARN_ON_ONCE(q->bypass_depth < 0); spin_unlock_irq(q->queue_lock); if (wake) wake_up_all(&q->mq_freeze_wq); } bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx) { return blk_mq_has_free_tags(hctx->tags); } EXPORT_SYMBOL(blk_mq_can_queue); static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx, struct request *rq, unsigned int rw_flags) { if (blk_queue_io_stat(q)) rw_flags |= REQ_IO_STAT; rq->mq_ctx = ctx; rq->cmd_flags = rw_flags; ctx->rq_dispatched[rw_is_sync(rw_flags)]++; } static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx, gfp_t gfp, bool reserved) { return blk_mq_alloc_rq(hctx, gfp, reserved); } static struct request *blk_mq_alloc_request_pinned(struct request_queue *q, int rw, gfp_t gfp, bool reserved) { struct request *rq; do { struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu); rq = __blk_mq_alloc_request(hctx, gfp & ~__GFP_WAIT, reserved); if (rq) { blk_mq_rq_ctx_init(q, ctx, rq, rw); break; } else if (!(gfp & __GFP_WAIT)) break; blk_mq_put_ctx(ctx); __blk_mq_run_hw_queue(hctx); blk_mq_wait_for_tags(hctx->tags); } while (1); return rq; } struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp, bool reserved) { struct request *rq; if (blk_mq_queue_enter(q)) return NULL; rq = blk_mq_alloc_request_pinned(q, rw, gfp, reserved); blk_mq_put_ctx(rq->mq_ctx); return rq; } struct request *blk_mq_alloc_reserved_request(struct request_queue *q, int rw, gfp_t gfp) { struct request *rq; if (blk_mq_queue_enter(q)) return NULL; rq = blk_mq_alloc_request_pinned(q, rw, gfp, true); blk_mq_put_ctx(rq->mq_ctx); return rq; } EXPORT_SYMBOL(blk_mq_alloc_reserved_request); /* * Re-init and set pdu, if we have it */ static void blk_mq_rq_init(struct blk_mq_hw_ctx *hctx, struct request *rq) { blk_rq_init(hctx->queue, rq); if (hctx->cmd_size) rq->special = blk_mq_rq_to_pdu(rq); } static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx, struct request *rq) { const int tag = rq->tag; struct request_queue *q = rq->q; blk_mq_rq_init(hctx, rq); blk_mq_put_tag(hctx->tags, tag); blk_mq_queue_exit(q); } void blk_mq_free_request(struct request *rq) { struct blk_mq_ctx *ctx = rq->mq_ctx; struct blk_mq_hw_ctx *hctx; struct request_queue *q = rq->q; ctx->rq_completed[rq_is_sync(rq)]++; hctx = q->mq_ops->map_queue(q, ctx->cpu); __blk_mq_free_request(hctx, ctx, rq); } static void blk_mq_bio_endio(struct request *rq, struct bio *bio, int error) { if (error) clear_bit(BIO_UPTODATE, &bio->bi_flags); else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) error = -EIO; if (unlikely(rq->cmd_flags & REQ_QUIET)) set_bit(BIO_QUIET, &bio->bi_flags); /* don't actually finish bio if it's part of flush sequence */ if (!(rq->cmd_flags & REQ_FLUSH_SEQ)) bio_endio(bio, error); } void blk_mq_complete_request(struct request *rq, int error) { struct bio *bio = rq->bio; unsigned int bytes = 0; trace_block_rq_complete(rq->q, rq); while (bio) { struct bio *next = bio->bi_next; bio->bi_next = NULL; bytes += bio->bi_size; blk_mq_bio_endio(rq, bio, error); bio = next; } blk_account_io_completion(rq, bytes); if (rq->end_io) rq->end_io(rq, error); else blk_mq_free_request(rq); blk_account_io_done(rq); } void __blk_mq_end_io(struct request *rq, int error) { if (!blk_mark_rq_complete(rq)) blk_mq_complete_request(rq, error); } #if defined(CONFIG_SMP) /* * Called with interrupts disabled. */ static void ipi_end_io(void *data) { struct llist_head *list = &per_cpu(ipi_lists, smp_processor_id()); struct llist_node *entry, *next; struct request *rq; entry = llist_del_all(list); while (entry) { next = entry->next; rq = llist_entry(entry, struct request, ll_list); __blk_mq_end_io(rq, rq->errors); entry = next; } } static int ipi_remote_cpu(struct blk_mq_ctx *ctx, const int cpu, struct request *rq, const int error) { struct call_single_data *data = &rq->csd; rq->errors = error; rq->ll_list.next = NULL; /* * If the list is non-empty, an existing IPI must already * be "in flight". If that is the case, we need not schedule * a new one. */ if (llist_add(&rq->ll_list, &per_cpu(ipi_lists, ctx->cpu))) { data->func = ipi_end_io; data->flags = 0; __smp_call_function_single(ctx->cpu, data, 0); } return true; } #else /* CONFIG_SMP */ static int ipi_remote_cpu(struct blk_mq_ctx *ctx, const int cpu, struct request *rq, const int error) { return false; } #endif /* * End IO on this request on a multiqueue enabled driver. We'll either do * it directly inline, or punt to a local IPI handler on the matching * remote CPU. */ void blk_mq_end_io(struct request *rq, int error) { struct blk_mq_ctx *ctx = rq->mq_ctx; int cpu; if (!ctx->ipi_redirect) return __blk_mq_end_io(rq, error); cpu = get_cpu(); if (cpu == ctx->cpu || !cpu_online(ctx->cpu) || !ipi_remote_cpu(ctx, cpu, rq, error)) __blk_mq_end_io(rq, error); put_cpu(); } EXPORT_SYMBOL(blk_mq_end_io); static void blk_mq_start_request(struct request *rq) { struct request_queue *q = rq->q; trace_block_rq_issue(q, rq); /* * Just mark start time and set the started bit. Due to memory * ordering, we know we'll see the correct deadline as long as * REQ_ATOMIC_STARTED is seen. */ rq->deadline = jiffies + q->rq_timeout; set_bit(REQ_ATOM_STARTED, &rq->atomic_flags); } static void blk_mq_requeue_request(struct request *rq) { struct request_queue *q = rq->q; trace_block_rq_requeue(q, rq); clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); } struct blk_mq_timeout_data { struct blk_mq_hw_ctx *hctx; unsigned long *next; unsigned int *next_set; }; static void blk_mq_timeout_check(void *__data, unsigned long *free_tags) { struct blk_mq_timeout_data *data = __data; struct blk_mq_hw_ctx *hctx = data->hctx; unsigned int tag; /* It may not be in flight yet (this is where * the REQ_ATOMIC_STARTED flag comes in). The requests are * statically allocated, so we know it's always safe to access the * memory associated with a bit offset into ->rqs[]. */ tag = 0; do { struct request *rq; tag = find_next_zero_bit(free_tags, hctx->queue_depth, tag); if (tag >= hctx->queue_depth) break; rq = hctx->rqs[tag++]; if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) continue; blk_rq_check_expired(rq, data->next, data->next_set); } while (1); } static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx *hctx, unsigned long *next, unsigned int *next_set) { struct blk_mq_timeout_data data = { .hctx = hctx, .next = next, .next_set = next_set, }; /* * Ask the tagging code to iterate busy requests, so we can * check them for timeout. */ blk_mq_tag_busy_iter(hctx->tags, blk_mq_timeout_check, &data); } static void blk_mq_rq_timer(unsigned long data) { struct request_queue *q = (struct request_queue *) data; struct blk_mq_hw_ctx *hctx; unsigned long next = 0; int i, next_set = 0; queue_for_each_hw_ctx(q, hctx, i) blk_mq_hw_ctx_check_timeout(hctx, &next, &next_set); if (next_set) mod_timer(&q->timeout, round_jiffies_up(next)); } /* * Reverse check our software queue for entries that we could potentially * merge with. Currently includes a hand-wavy stop count of 8, to not spend * too much time checking for merges. */ static bool blk_mq_attempt_merge(struct request_queue *q, struct blk_mq_ctx *ctx, struct bio *bio) { struct request *rq; int checked = 8; list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { int el_ret; if (!checked--) break; if (!blk_rq_merge_ok(rq, bio)) continue; el_ret = blk_try_merge(rq, bio); if (el_ret == ELEVATOR_BACK_MERGE) { if (bio_attempt_back_merge(q, rq, bio)) { ctx->rq_merged++; return true; } break; } else if (el_ret == ELEVATOR_FRONT_MERGE) { if (bio_attempt_front_merge(q, rq, bio)) { ctx->rq_merged++; return true; } break; } } return false; } void blk_mq_add_timer(struct request *rq) { __blk_add_timer(rq, NULL); } /* * Run this hardware queue, pulling any software queues mapped to it in. * Note that this function currently has various problems around ordering * of IO. In particular, we'd like FIFO behaviour on handling existing * items on the hctx->dispatch list. Ignore that for now. */ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; struct blk_mq_ctx *ctx; struct request *rq; LIST_HEAD(rq_list); int bit, queued; if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->flags))) return; hctx->run++; /* * Touch any software queue that has pending entries. */ for_each_set_bit(bit, hctx->ctx_map, hctx->nr_ctx) { clear_bit(bit, hctx->ctx_map); ctx = hctx->ctxs[bit]; BUG_ON(bit != ctx->index_hw); spin_lock(&ctx->lock); list_splice_tail_init(&ctx->rq_list, &rq_list); spin_unlock(&ctx->lock); } /* * If we have previous entries on our dispatch list, grab them * and stuff them at the front for more fair dispatch. */ if (!list_empty_careful(&hctx->dispatch)) { spin_lock(&hctx->lock); if (!list_empty(&hctx->dispatch)) list_splice_init(&hctx->dispatch, &rq_list); spin_unlock(&hctx->lock); } /* * Delete and return all entries from our dispatch list */ queued = 0; /* * Now process all the entries, sending them to the driver. */ while (!list_empty(&rq_list)) { int ret; rq = list_first_entry(&rq_list, struct request, queuelist); list_del_init(&rq->queuelist); blk_mq_start_request(rq); /* * Last request in the series. Flag it as such, this * enables drivers to know when IO should be kicked off, * if they don't do it on a per-request basis. * * Note: the flag isn't the only condition drivers * should do kick off. If drive is busy, the last * request might not have the bit set. */ if (list_empty(&rq_list)) rq->cmd_flags |= REQ_END; ret = q->mq_ops->queue_rq(hctx, rq); switch (ret) { case BLK_MQ_RQ_QUEUE_OK: queued++; continue; case BLK_MQ_RQ_QUEUE_BUSY: /* * FIXME: we should have a mechanism to stop the queue * like blk_stop_queue, otherwise we will waste cpu * time */ list_add(&rq->queuelist, &rq_list); blk_mq_requeue_request(rq); break; default: pr_err("blk-mq: bad return on queue: %d\n", ret); rq->errors = -EIO; case BLK_MQ_RQ_QUEUE_ERROR: blk_mq_end_io(rq, rq->errors); break; } if (ret == BLK_MQ_RQ_QUEUE_BUSY) break; } if (!queued) hctx->dispatched[0]++; else if (queued < (1 << (BLK_MQ_MAX_DISPATCH_ORDER - 1))) hctx->dispatched[ilog2(queued) + 1]++; /* * Any items that need requeuing? Stuff them into hctx->dispatch, * that is where we will continue on next queue run. */ if (!list_empty(&rq_list)) { spin_lock(&hctx->lock); list_splice(&rq_list, &hctx->dispatch); spin_unlock(&hctx->lock); } } void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) { if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->flags))) return; if (!async) __blk_mq_run_hw_queue(hctx); else { struct request_queue *q = hctx->queue; kblockd_schedule_delayed_work(q, &hctx->delayed_work, 0); } } void blk_mq_run_queues(struct request_queue *q, bool async) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) { if ((!blk_mq_hctx_has_pending(hctx) && list_empty_careful(&hctx->dispatch)) || test_bit(BLK_MQ_S_STOPPED, &hctx->flags)) continue; blk_mq_run_hw_queue(hctx, async); } } EXPORT_SYMBOL(blk_mq_run_queues); void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) { cancel_delayed_work(&hctx->delayed_work); set_bit(BLK_MQ_S_STOPPED, &hctx->state); } EXPORT_SYMBOL(blk_mq_stop_hw_queue); void blk_mq_stop_hw_queues(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) blk_mq_stop_hw_queue(hctx); } EXPORT_SYMBOL(blk_mq_stop_hw_queues); void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx) { clear_bit(BLK_MQ_S_STOPPED, &hctx->state); __blk_mq_run_hw_queue(hctx); } EXPORT_SYMBOL(blk_mq_start_hw_queue); void blk_mq_start_stopped_hw_queues(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) { if (!test_bit(BLK_MQ_S_STOPPED, &hctx->state)) continue; clear_bit(BLK_MQ_S_STOPPED, &hctx->state); blk_mq_run_hw_queue(hctx, true); } } EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); static void blk_mq_work_fn(struct work_struct *work) { struct blk_mq_hw_ctx *hctx; hctx = container_of(work, struct blk_mq_hw_ctx, delayed_work.work); __blk_mq_run_hw_queue(hctx); } static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq) { struct blk_mq_ctx *ctx = rq->mq_ctx; trace_block_rq_insert(hctx->queue, rq); list_add_tail(&rq->queuelist, &ctx->rq_list); blk_mq_hctx_mark_pending(hctx, ctx); /* * We do this early, to ensure we are on the right CPU. */ blk_mq_add_timer(rq); } void blk_mq_insert_request(struct request_queue *q, struct request *rq, bool run_queue) { struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *ctx, *current_ctx; ctx = rq->mq_ctx; hctx = q->mq_ops->map_queue(q, ctx->cpu); if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) { blk_insert_flush(rq); } else { current_ctx = blk_mq_get_ctx(q); if (!cpu_online(ctx->cpu)) { ctx = current_ctx; hctx = q->mq_ops->map_queue(q, ctx->cpu); rq->mq_ctx = ctx; } spin_lock(&ctx->lock); __blk_mq_insert_request(hctx, rq); spin_unlock(&ctx->lock); blk_mq_put_ctx(current_ctx); } if (run_queue) __blk_mq_run_hw_queue(hctx); } EXPORT_SYMBOL(blk_mq_insert_request); /* * This is a special version of blk_mq_insert_request to bypass FLUSH request * check. Should only be used internally. */ void blk_mq_run_request(struct request *rq, bool run_queue, bool async) { struct request_queue *q = rq->q; struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *ctx, *current_ctx; current_ctx = blk_mq_get_ctx(q); ctx = rq->mq_ctx; if (!cpu_online(ctx->cpu)) { ctx = current_ctx; rq->mq_ctx = ctx; } hctx = q->mq_ops->map_queue(q, ctx->cpu); /* ctx->cpu might be offline */ spin_lock(&ctx->lock); __blk_mq_insert_request(hctx, rq); spin_unlock(&ctx->lock); blk_mq_put_ctx(current_ctx); if (run_queue) blk_mq_run_hw_queue(hctx, async); } static void blk_mq_insert_requests(struct request_queue *q, struct blk_mq_ctx *ctx, struct list_head *list, int depth, bool from_schedule) { struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *current_ctx; trace_block_unplug(q, depth, !from_schedule); current_ctx = blk_mq_get_ctx(q); if (!cpu_online(ctx->cpu)) ctx = current_ctx; hctx = q->mq_ops->map_queue(q, ctx->cpu); /* * preemption doesn't flush plug list, so it's possible ctx->cpu is * offline now */ spin_lock(&ctx->lock); while (!list_empty(list)) { struct request *rq; rq = list_first_entry(list, struct request, queuelist); list_del_init(&rq->queuelist); rq->mq_ctx = ctx; __blk_mq_insert_request(hctx, rq); } spin_unlock(&ctx->lock); blk_mq_put_ctx(current_ctx); blk_mq_run_hw_queue(hctx, from_schedule); } static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b) { struct request *rqa = container_of(a, struct request, queuelist); struct request *rqb = container_of(b, struct request, queuelist); return !(rqa->mq_ctx < rqb->mq_ctx || (rqa->mq_ctx == rqb->mq_ctx && blk_rq_pos(rqa) < blk_rq_pos(rqb))); } void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) { struct blk_mq_ctx *this_ctx; struct request_queue *this_q; struct request *rq; LIST_HEAD(list); LIST_HEAD(ctx_list); unsigned int depth; list_splice_init(&plug->mq_list, &list); list_sort(NULL, &list, plug_ctx_cmp); this_q = NULL; this_ctx = NULL; depth = 0; while (!list_empty(&list)) { rq = list_entry_rq(list.next); list_del_init(&rq->queuelist); BUG_ON(!rq->q); if (rq->mq_ctx != this_ctx) { if (this_ctx) { blk_mq_insert_requests(this_q, this_ctx, &ctx_list, depth, from_schedule); } this_ctx = rq->mq_ctx; this_q = rq->q; depth = 0; } depth++; list_add_tail(&rq->queuelist, &ctx_list); } /* * If 'this_ctx' is set, we know we have entries to complete * on 'ctx_list'. Do those. */ if (this_ctx) { blk_mq_insert_requests(this_q, this_ctx, &ctx_list, depth, from_schedule); } } static void blk_mq_bio_to_request(struct request *rq, struct bio *bio) { init_request_from_bio(rq, bio); blk_account_io_start(rq, 1); } static void blk_mq_make_request(struct request_queue *q, struct bio *bio) { struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *ctx; const int is_sync = rw_is_sync(bio->bi_rw); const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA); int rw = bio_data_dir(bio); struct request *rq; unsigned int use_plug, request_count = 0; /* * If we have multiple hardware queues, just go directly to * one of those for sync IO. */ use_plug = !is_flush_fua && ((q->nr_hw_queues == 1) || !is_sync); blk_queue_bounce(q, &bio); if (use_plug && blk_attempt_plug_merge(q, bio, &request_count)) return; if (blk_mq_queue_enter(q)) { bio_endio(bio, -EIO); return; } ctx = blk_mq_get_ctx(q); hctx = q->mq_ops->map_queue(q, ctx->cpu); trace_block_getrq(q, bio, rw); rq = __blk_mq_alloc_request(hctx, GFP_ATOMIC, false); if (likely(rq)) blk_mq_rq_ctx_init(q, ctx, rq, rw); else { blk_mq_put_ctx(ctx); trace_block_sleeprq(q, bio, rw); rq = blk_mq_alloc_request_pinned(q, rw, __GFP_WAIT|GFP_ATOMIC, false); ctx = rq->mq_ctx; hctx = q->mq_ops->map_queue(q, ctx->cpu); } hctx->queued++; if (unlikely(is_flush_fua)) { blk_mq_bio_to_request(rq, bio); blk_mq_put_ctx(ctx); blk_insert_flush(rq); goto run_queue; } /* * A task plug currently exists. Since this is completely lockless, * utilize that to temporarily store requests until the task is * either done or scheduled away. */ if (use_plug) { struct blk_plug *plug = current->plug; if (plug) { blk_mq_bio_to_request(rq, bio); if (list_empty(&plug->mq_list)) trace_block_plug(q); else if (request_count >= BLK_MAX_REQUEST_COUNT) { blk_flush_plug_list(plug, false); trace_block_plug(q); } list_add_tail(&rq->queuelist, &plug->mq_list); blk_mq_put_ctx(ctx); return; } } spin_lock(&ctx->lock); if ((hctx->flags & BLK_MQ_F_SHOULD_MERGE) && blk_mq_attempt_merge(q, ctx, bio)) __blk_mq_free_request(hctx, ctx, rq); else { blk_mq_bio_to_request(rq, bio); __blk_mq_insert_request(hctx, rq); } spin_unlock(&ctx->lock); blk_mq_put_ctx(ctx); /* * For a SYNC request, send it to the hardware immediately. For an * ASYNC request, just ensure that we run it later on. The latter * allows for merging opportunities and more efficient dispatching. */ run_queue: blk_mq_run_hw_queue(hctx, !is_sync || is_flush_fua); } /* * Default mapping to a software queue, since we use one per CPU. */ struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q, const int cpu) { return q->queue_hw_ctx[q->mq_map[cpu]]; } EXPORT_SYMBOL(blk_mq_map_queue); struct blk_mq_hw_ctx *blk_mq_alloc_single_hw_queue(struct blk_mq_reg *reg, unsigned int hctx_index) { return kmalloc_node(sizeof(struct blk_mq_hw_ctx), GFP_KERNEL | __GFP_ZERO, reg->numa_node); } EXPORT_SYMBOL(blk_mq_alloc_single_hw_queue); void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned int hctx_index) { kfree(hctx); } EXPORT_SYMBOL(blk_mq_free_single_hw_queue); static void blk_mq_hctx_notify(void *data, unsigned long action, unsigned int cpu) { struct blk_mq_hw_ctx *hctx = data; struct blk_mq_ctx *ctx; LIST_HEAD(tmp); if (action != CPU_DEAD && action != CPU_DEAD_FROZEN) return; /* * Move ctx entries to new CPU, if this one is going away. */ ctx = __blk_mq_get_ctx(hctx->queue, cpu); spin_lock(&ctx->lock); if (!list_empty(&ctx->rq_list)) { list_splice_init(&ctx->rq_list, &tmp); clear_bit(ctx->index_hw, hctx->ctx_map); } spin_unlock(&ctx->lock); if (list_empty(&tmp)) return; ctx = blk_mq_get_ctx(hctx->queue); spin_lock(&ctx->lock); while (!list_empty(&tmp)) { struct request *rq; rq = list_first_entry(&tmp, struct request, queuelist); rq->mq_ctx = ctx; list_move_tail(&rq->queuelist, &ctx->rq_list); } blk_mq_hctx_mark_pending(hctx, ctx); spin_unlock(&ctx->lock); blk_mq_put_ctx(ctx); } static void blk_mq_init_hw_commands(struct blk_mq_hw_ctx *hctx, void (*init)(void *, struct blk_mq_hw_ctx *, struct request *, unsigned int), void *data) { unsigned int i; for (i = 0; i < hctx->queue_depth; i++) { struct request *rq = hctx->rqs[i]; init(data, hctx, rq, i); } } void blk_mq_init_commands(struct request_queue *q, void (*init)(void *, struct blk_mq_hw_ctx *, struct request *, unsigned int), void *data) { struct blk_mq_hw_ctx *hctx; unsigned int i; queue_for_each_hw_ctx(q, hctx, i) blk_mq_init_hw_commands(hctx, init, data); } EXPORT_SYMBOL(blk_mq_init_commands); static void blk_mq_free_rq_map(struct blk_mq_hw_ctx *hctx) { struct page *page; while (!list_empty(&hctx->page_list)) { page = list_first_entry(&hctx->page_list, struct page, list); list_del_init(&page->list); __free_pages(page, page->private); } kfree(hctx->rqs); if (hctx->tags) blk_mq_free_tags(hctx->tags); } static size_t order_to_size(unsigned int order) { size_t ret = PAGE_SIZE; while (order--) ret *= 2; return ret; } static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx, unsigned int reserved_tags, int node) { unsigned int i, j, entries_per_page, max_order = 4; size_t rq_size, left; INIT_LIST_HEAD(&hctx->page_list); hctx->rqs = kmalloc_node(hctx->queue_depth * sizeof(struct request *), GFP_KERNEL, node); if (!hctx->rqs) return -ENOMEM; /* * rq_size is the size of the request plus driver payload, rounded * to the cacheline size */ rq_size = round_up(sizeof(struct request) + hctx->cmd_size, cache_line_size()); left = rq_size * hctx->queue_depth; for (i = 0; i < hctx->queue_depth;) { int this_order = max_order; struct page *page; int to_do; void *p; while (left < order_to_size(this_order - 1) && this_order) this_order--; do { page = alloc_pages_node(node, GFP_KERNEL, this_order); if (page) break; if (!this_order--) break; if (order_to_size(this_order) < rq_size) break; } while (1); if (!page) break; page->private = this_order; list_add_tail(&page->list, &hctx->page_list); p = page_address(page); entries_per_page = order_to_size(this_order) / rq_size; to_do = min(entries_per_page, hctx->queue_depth - i); left -= to_do * rq_size; for (j = 0; j < to_do; j++) { hctx->rqs[i] = p; blk_mq_rq_init(hctx, hctx->rqs[i]); p += rq_size; i++; } } if (i < (reserved_tags + BLK_MQ_TAG_MIN)) goto err_rq_map; else if (i != hctx->queue_depth) { hctx->queue_depth = i; pr_warn("%s: queue depth set to %u because of low memory\n", __func__, i); } hctx->tags = blk_mq_init_tags(hctx->queue_depth, reserved_tags, node); if (!hctx->tags) { err_rq_map: blk_mq_free_rq_map(hctx); return -ENOMEM; } return 0; } static int blk_mq_init_hw_queues(struct request_queue *q, struct blk_mq_reg *reg, void *driver_data) { struct blk_mq_hw_ctx *hctx; unsigned int i, j; /* * Initialize hardware queues */ queue_for_each_hw_ctx(q, hctx, i) { unsigned int num_maps; int node; node = hctx->numa_node; if (node == NUMA_NO_NODE) node = hctx->numa_node = reg->numa_node; INIT_DELAYED_WORK(&hctx->delayed_work, blk_mq_work_fn); spin_lock_init(&hctx->lock); INIT_LIST_HEAD(&hctx->dispatch); hctx->queue = q; hctx->queue_num = i; hctx->flags = reg->flags; hctx->queue_depth = reg->queue_depth; hctx->cmd_size = reg->cmd_size; blk_mq_init_cpu_notifier(&hctx->cpu_notifier, blk_mq_hctx_notify, hctx); blk_mq_register_cpu_notifier(&hctx->cpu_notifier); if (blk_mq_init_rq_map(hctx, reg->reserved_tags, node)) break; /* * Allocate space for all possible cpus to avoid allocation in * runtime */ hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *), GFP_KERNEL, node); if (!hctx->ctxs) break; num_maps = ALIGN(nr_cpu_ids, BITS_PER_LONG) / BITS_PER_LONG; hctx->ctx_map = kzalloc_node(num_maps * sizeof(unsigned long), GFP_KERNEL, node); if (!hctx->ctx_map) break; hctx->nr_ctx_map = num_maps; hctx->nr_ctx = 0; if (reg->ops->init_hctx && reg->ops->init_hctx(hctx, driver_data, i)) break; } if (i == q->nr_hw_queues) return 0; /* * Init failed */ queue_for_each_hw_ctx(q, hctx, j) { if (i == j) break; if (reg->ops->exit_hctx) reg->ops->exit_hctx(hctx, j); blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); blk_mq_free_rq_map(hctx); kfree(hctx->ctxs); } return 1; } static void blk_mq_init_cpu_queues(struct request_queue *q, unsigned int nr_hw_queues) { unsigned int i; for_each_possible_cpu(i) { struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i); struct blk_mq_hw_ctx *hctx; memset(__ctx, 0, sizeof(*__ctx)); __ctx->cpu = i; spin_lock_init(&__ctx->lock); INIT_LIST_HEAD(&__ctx->rq_list); __ctx->queue = q; /* If the cpu isn't online, the cpu is mapped to first hctx */ hctx = q->mq_ops->map_queue(q, i); hctx->nr_ctx++; if (!cpu_online(i)) continue; /* * Set local node, IFF we have more than one hw queue. If * not, we remain on the home node of the device */ if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE) hctx->numa_node = cpu_to_node(i); } } static void blk_mq_map_swqueue(struct request_queue *q) { unsigned int i; struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *ctx; queue_for_each_hw_ctx(q, hctx, i) { hctx->nr_ctx = 0; } /* * Map software to hardware queues */ queue_for_each_ctx(q, ctx, i) { /* If the cpu isn't online, the cpu is mapped to first hctx */ hctx = q->mq_ops->map_queue(q, i); ctx->index_hw = hctx->nr_ctx; hctx->ctxs[hctx->nr_ctx++] = ctx; } } struct request_queue *blk_mq_init_queue(struct blk_mq_reg *reg, void *driver_data) { struct blk_mq_hw_ctx **hctxs; struct blk_mq_ctx *ctx; struct request_queue *q; int i; if (!reg->nr_hw_queues || !reg->ops->queue_rq || !reg->ops->map_queue || !reg->ops->alloc_hctx || !reg->ops->free_hctx) return ERR_PTR(-EINVAL); if (!reg->queue_depth) reg->queue_depth = BLK_MQ_MAX_DEPTH; else if (reg->queue_depth > BLK_MQ_MAX_DEPTH) { pr_err("blk-mq: queuedepth too large (%u)\n", reg->queue_depth); reg->queue_depth = BLK_MQ_MAX_DEPTH; } /* * Set aside a tag for flush requests. It will only be used while * another flush request is in progress but outside the driver. * * TODO: only allocate if flushes are supported */ reg->queue_depth++; reg->reserved_tags++; if (reg->queue_depth < (reg->reserved_tags + BLK_MQ_TAG_MIN)) return ERR_PTR(-EINVAL); ctx = alloc_percpu(struct blk_mq_ctx); if (!ctx) return ERR_PTR(-ENOMEM); hctxs = kmalloc_node(reg->nr_hw_queues * sizeof(*hctxs), GFP_KERNEL, reg->numa_node); if (!hctxs) goto err_percpu; for (i = 0; i < reg->nr_hw_queues; i++) { hctxs[i] = reg->ops->alloc_hctx(reg, i); if (!hctxs[i]) goto err_hctxs; hctxs[i]->numa_node = NUMA_NO_NODE; hctxs[i]->queue_num = i; } q = blk_alloc_queue_node(GFP_KERNEL, reg->numa_node); if (!q) goto err_hctxs; q->mq_map = blk_mq_make_queue_map(reg); if (!q->mq_map) goto err_map; setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q); blk_queue_rq_timeout(q, 30000); q->nr_queues = nr_cpu_ids; q->nr_hw_queues = reg->nr_hw_queues; q->queue_ctx = ctx; q->queue_hw_ctx = hctxs; q->mq_ops = reg->ops; q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; blk_queue_make_request(q, blk_mq_make_request); blk_queue_rq_timed_out(q, reg->ops->timeout); if (reg->timeout) blk_queue_rq_timeout(q, reg->timeout); blk_mq_init_flush(q); blk_mq_init_cpu_queues(q, reg->nr_hw_queues); if (blk_mq_init_hw_queues(q, reg, driver_data)) goto err_hw; blk_mq_map_swqueue(q); mutex_lock(&all_q_mutex); list_add_tail(&q->all_q_node, &all_q_list); mutex_unlock(&all_q_mutex); return q; err_hw: kfree(q->mq_map); err_map: blk_cleanup_queue(q); err_hctxs: for (i = 0; i < reg->nr_hw_queues; i++) { if (!hctxs[i]) break; reg->ops->free_hctx(hctxs[i], i); } kfree(hctxs); err_percpu: free_percpu(ctx); return ERR_PTR(-ENOMEM); } EXPORT_SYMBOL(blk_mq_init_queue); void blk_mq_free_queue(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) { cancel_delayed_work_sync(&hctx->delayed_work); kfree(hctx->ctx_map); kfree(hctx->ctxs); blk_mq_free_rq_map(hctx); blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); if (q->mq_ops->exit_hctx) q->mq_ops->exit_hctx(hctx, i); q->mq_ops->free_hctx(hctx, i); } free_percpu(q->queue_ctx); kfree(q->queue_hw_ctx); kfree(q->mq_map); q->queue_ctx = NULL; q->queue_hw_ctx = NULL; q->mq_map = NULL; mutex_lock(&all_q_mutex); list_del_init(&q->all_q_node); mutex_unlock(&all_q_mutex); } EXPORT_SYMBOL(blk_mq_free_queue); /* Basically redo blk_mq_init_queue with queue frozen */ static void blk_mq_queue_reinit(struct request_queue *q) { blk_mq_freeze_queue(q); blk_mq_update_queue_map(q->mq_map, q->nr_hw_queues); /* * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe * we should change hctx numa_node according to new topology (this * involves free and re-allocate memory, worthy doing?) */ blk_mq_map_swqueue(q); blk_mq_unfreeze_queue(q); } static int blk_mq_queue_reinit_notify(struct notifier_block *nb, unsigned long action, void *hcpu) { struct request_queue *q; /* * Before new mapping is established, hotadded cpu might already start * handling requests. This doesn't break anything as we map offline * CPUs to first hardware queue. We will re-init queue below to get * optimal settings. */ if (action != CPU_DEAD && action != CPU_DEAD_FROZEN && action != CPU_ONLINE && action != CPU_ONLINE_FROZEN) return NOTIFY_OK; mutex_lock(&all_q_mutex); list_for_each_entry(q, &all_q_list, all_q_node) blk_mq_queue_reinit(q); mutex_unlock(&all_q_mutex); return NOTIFY_OK; } static int __init blk_mq_init(void) { unsigned int i; for_each_possible_cpu(i) init_llist_head(&per_cpu(ipi_lists, i)); blk_mq_cpu_init(); /* Must be called after percpu_counter_hotcpu_callback() */ hotcpu_notifier(blk_mq_queue_reinit_notify, -10); return 0; } subsys_initcall(blk_mq_init);