| /* |
| * Block multiqueue core code |
| * |
| * Copyright (C) 2013-2014 Jens Axboe |
| * Copyright (C) 2013-2014 Christoph Hellwig |
| */ |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/backing-dev.h> |
| #include <linux/bio.h> |
| #include <linux/blkdev.h> |
| #include <linux/kmemleak.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 <linux/crash_dump.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); |
| |
| /* |
| * 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->ctx_map.size; i++) |
| if (hctx->ctx_map.map[i].word) |
| return true; |
| |
| return false; |
| } |
| |
| static inline struct blk_align_bitmap *get_bm(struct blk_mq_hw_ctx *hctx, |
| struct blk_mq_ctx *ctx) |
| { |
| return &hctx->ctx_map.map[ctx->index_hw / hctx->ctx_map.bits_per_word]; |
| } |
| |
| #define CTX_TO_BIT(hctx, ctx) \ |
| ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1)) |
| |
| /* |
| * 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) |
| { |
| struct blk_align_bitmap *bm = get_bm(hctx, ctx); |
| |
| if (!test_bit(CTX_TO_BIT(hctx, ctx), &bm->word)) |
| set_bit(CTX_TO_BIT(hctx, ctx), &bm->word); |
| } |
| |
| static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, |
| struct blk_mq_ctx *ctx) |
| { |
| struct blk_align_bitmap *bm = get_bm(hctx, ctx); |
| |
| clear_bit(CTX_TO_BIT(hctx, ctx), &bm->word); |
| } |
| |
| void blk_mq_freeze_queue_start(struct request_queue *q) |
| { |
| int freeze_depth; |
| |
| freeze_depth = atomic_inc_return(&q->mq_freeze_depth); |
| if (freeze_depth == 1) { |
| percpu_ref_kill(&q->q_usage_counter); |
| blk_mq_run_hw_queues(q, false); |
| } |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start); |
| |
| static void blk_mq_freeze_queue_wait(struct request_queue *q) |
| { |
| wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter)); |
| } |
| |
| /* |
| * Guarantee no request is in use, so we can change any data structure of |
| * the queue afterward. |
| */ |
| void blk_freeze_queue(struct request_queue *q) |
| { |
| /* |
| * In the !blk_mq case we are only calling this to kill the |
| * q_usage_counter, otherwise this increases the freeze depth |
| * and waits for it to return to zero. For this reason there is |
| * no blk_unfreeze_queue(), and blk_freeze_queue() is not |
| * exported to drivers as the only user for unfreeze is blk_mq. |
| */ |
| blk_mq_freeze_queue_start(q); |
| blk_mq_freeze_queue_wait(q); |
| } |
| |
| void blk_mq_freeze_queue(struct request_queue *q) |
| { |
| /* |
| * ...just an alias to keep freeze and unfreeze actions balanced |
| * in the blk_mq_* namespace |
| */ |
| blk_freeze_queue(q); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_freeze_queue); |
| |
| void blk_mq_unfreeze_queue(struct request_queue *q) |
| { |
| int freeze_depth; |
| |
| freeze_depth = atomic_dec_return(&q->mq_freeze_depth); |
| WARN_ON_ONCE(freeze_depth < 0); |
| if (!freeze_depth) { |
| percpu_ref_reinit(&q->q_usage_counter); |
| wake_up_all(&q->mq_freeze_wq); |
| } |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); |
| |
| void blk_mq_wake_waiters(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| if (blk_mq_hw_queue_mapped(hctx)) |
| blk_mq_tag_wakeup_all(hctx->tags, true); |
| |
| /* |
| * If we are called because the queue has now been marked as |
| * dying, we need to ensure that processes currently waiting on |
| * the queue are notified as well. |
| */ |
| 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; |
| |
| INIT_LIST_HEAD(&rq->queuelist); |
| /* csd/requeue_work/fifo_time is initialized before use */ |
| rq->q = q; |
| rq->mq_ctx = ctx; |
| rq->cmd_flags |= rw_flags; |
| /* do not touch atomic flags, it needs atomic ops against the timer */ |
| rq->cpu = -1; |
| INIT_HLIST_NODE(&rq->hash); |
| RB_CLEAR_NODE(&rq->rb_node); |
| rq->rq_disk = NULL; |
| rq->part = NULL; |
| rq->start_time = jiffies; |
| #ifdef CONFIG_BLK_CGROUP |
| rq->rl = NULL; |
| set_start_time_ns(rq); |
| rq->io_start_time_ns = 0; |
| #endif |
| rq->nr_phys_segments = 0; |
| #if defined(CONFIG_BLK_DEV_INTEGRITY) |
| rq->nr_integrity_segments = 0; |
| #endif |
| rq->special = NULL; |
| /* tag was already set */ |
| rq->errors = 0; |
| |
| rq->cmd = rq->__cmd; |
| |
| rq->extra_len = 0; |
| rq->sense_len = 0; |
| rq->resid_len = 0; |
| rq->sense = NULL; |
| |
| INIT_LIST_HEAD(&rq->timeout_list); |
| rq->timeout = 0; |
| |
| rq->end_io = NULL; |
| rq->end_io_data = NULL; |
| rq->next_rq = NULL; |
| |
| ctx->rq_dispatched[rw_is_sync(rw_flags)]++; |
| } |
| |
| static struct request * |
| __blk_mq_alloc_request(struct blk_mq_alloc_data *data, int rw) |
| { |
| struct request *rq; |
| unsigned int tag; |
| |
| tag = blk_mq_get_tag(data); |
| if (tag != BLK_MQ_TAG_FAIL) { |
| rq = data->hctx->tags->rqs[tag]; |
| |
| if (blk_mq_tag_busy(data->hctx)) { |
| rq->cmd_flags = REQ_MQ_INFLIGHT; |
| atomic_inc(&data->hctx->nr_active); |
| } |
| |
| rq->tag = tag; |
| blk_mq_rq_ctx_init(data->q, data->ctx, rq, rw); |
| return rq; |
| } |
| |
| return NULL; |
| } |
| |
| struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp, |
| bool reserved) |
| { |
| struct blk_mq_ctx *ctx; |
| struct blk_mq_hw_ctx *hctx; |
| struct request *rq; |
| struct blk_mq_alloc_data alloc_data; |
| int ret; |
| |
| ret = blk_queue_enter(q, gfp); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| ctx = blk_mq_get_ctx(q); |
| hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| blk_mq_set_alloc_data(&alloc_data, q, gfp & ~__GFP_DIRECT_RECLAIM, |
| reserved, ctx, hctx); |
| |
| rq = __blk_mq_alloc_request(&alloc_data, rw); |
| if (!rq && (gfp & __GFP_DIRECT_RECLAIM)) { |
| __blk_mq_run_hw_queue(hctx); |
| blk_mq_put_ctx(ctx); |
| |
| ctx = blk_mq_get_ctx(q); |
| hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| blk_mq_set_alloc_data(&alloc_data, q, gfp, reserved, ctx, |
| hctx); |
| rq = __blk_mq_alloc_request(&alloc_data, rw); |
| ctx = alloc_data.ctx; |
| } |
| blk_mq_put_ctx(ctx); |
| if (!rq) { |
| blk_queue_exit(q); |
| return ERR_PTR(-EWOULDBLOCK); |
| } |
| return rq; |
| } |
| EXPORT_SYMBOL(blk_mq_alloc_request); |
| |
| 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; |
| |
| if (rq->cmd_flags & REQ_MQ_INFLIGHT) |
| atomic_dec(&hctx->nr_active); |
| rq->cmd_flags = 0; |
| |
| clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); |
| blk_mq_put_tag(hctx, tag, &ctx->last_tag); |
| blk_queue_exit(q); |
| } |
| |
| void blk_mq_free_hctx_request(struct blk_mq_hw_ctx *hctx, struct request *rq) |
| { |
| struct blk_mq_ctx *ctx = rq->mq_ctx; |
| |
| ctx->rq_completed[rq_is_sync(rq)]++; |
| __blk_mq_free_request(hctx, ctx, rq); |
| |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_free_hctx_request); |
| |
| void blk_mq_free_request(struct request *rq) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| struct request_queue *q = rq->q; |
| |
| hctx = q->mq_ops->map_queue(q, rq->mq_ctx->cpu); |
| blk_mq_free_hctx_request(hctx, rq); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_free_request); |
| |
| inline void __blk_mq_end_request(struct request *rq, int error) |
| { |
| blk_account_io_done(rq); |
| |
| if (rq->end_io) { |
| rq->end_io(rq, error); |
| } else { |
| if (unlikely(blk_bidi_rq(rq))) |
| blk_mq_free_request(rq->next_rq); |
| blk_mq_free_request(rq); |
| } |
| } |
| EXPORT_SYMBOL(__blk_mq_end_request); |
| |
| void blk_mq_end_request(struct request *rq, int error) |
| { |
| if (blk_update_request(rq, error, blk_rq_bytes(rq))) |
| BUG(); |
| __blk_mq_end_request(rq, error); |
| } |
| EXPORT_SYMBOL(blk_mq_end_request); |
| |
| static void __blk_mq_complete_request_remote(void *data) |
| { |
| struct request *rq = data; |
| |
| rq->q->softirq_done_fn(rq); |
| } |
| |
| static void blk_mq_ipi_complete_request(struct request *rq) |
| { |
| struct blk_mq_ctx *ctx = rq->mq_ctx; |
| bool shared = false; |
| int cpu; |
| |
| if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) { |
| rq->q->softirq_done_fn(rq); |
| return; |
| } |
| |
| cpu = get_cpu(); |
| if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags)) |
| shared = cpus_share_cache(cpu, ctx->cpu); |
| |
| if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) { |
| rq->csd.func = __blk_mq_complete_request_remote; |
| rq->csd.info = rq; |
| rq->csd.flags = 0; |
| smp_call_function_single_async(ctx->cpu, &rq->csd); |
| } else { |
| rq->q->softirq_done_fn(rq); |
| } |
| put_cpu(); |
| } |
| |
| static void __blk_mq_complete_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| |
| if (!q->softirq_done_fn) |
| blk_mq_end_request(rq, rq->errors); |
| else |
| blk_mq_ipi_complete_request(rq); |
| } |
| |
| /** |
| * blk_mq_complete_request - end I/O on a request |
| * @rq: the request being processed |
| * |
| * Description: |
| * Ends all I/O on a request. It does not handle partial completions. |
| * The actual completion happens out-of-order, through a IPI handler. |
| **/ |
| void blk_mq_complete_request(struct request *rq, int error) |
| { |
| struct request_queue *q = rq->q; |
| |
| if (unlikely(blk_should_fake_timeout(q))) |
| return; |
| if (!blk_mark_rq_complete(rq)) { |
| rq->errors = error; |
| __blk_mq_complete_request(rq); |
| } |
| } |
| EXPORT_SYMBOL(blk_mq_complete_request); |
| |
| int blk_mq_request_started(struct request *rq) |
| { |
| return test_bit(REQ_ATOM_STARTED, &rq->atomic_flags); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_request_started); |
| |
| void blk_mq_start_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| |
| trace_block_rq_issue(q, rq); |
| |
| rq->resid_len = blk_rq_bytes(rq); |
| if (unlikely(blk_bidi_rq(rq))) |
| rq->next_rq->resid_len = blk_rq_bytes(rq->next_rq); |
| |
| blk_add_timer(rq); |
| |
| /* |
| * Ensure that ->deadline is visible before set the started |
| * flag and clear the completed flag. |
| */ |
| smp_mb__before_atomic(); |
| |
| /* |
| * Mark us as started and clear complete. Complete might have been |
| * set if requeue raced with timeout, which then marked it as |
| * complete. So be sure to clear complete again when we start |
| * the request, otherwise we'll ignore the completion event. |
| */ |
| if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) |
| set_bit(REQ_ATOM_STARTED, &rq->atomic_flags); |
| if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) |
| clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); |
| |
| if (q->dma_drain_size && blk_rq_bytes(rq)) { |
| /* |
| * Make sure space for the drain appears. We know we can do |
| * this because max_hw_segments has been adjusted to be one |
| * fewer than the device can handle. |
| */ |
| rq->nr_phys_segments++; |
| } |
| } |
| EXPORT_SYMBOL(blk_mq_start_request); |
| |
| static void __blk_mq_requeue_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| |
| trace_block_rq_requeue(q, rq); |
| |
| if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) { |
| if (q->dma_drain_size && blk_rq_bytes(rq)) |
| rq->nr_phys_segments--; |
| } |
| } |
| |
| void blk_mq_requeue_request(struct request *rq) |
| { |
| __blk_mq_requeue_request(rq); |
| |
| BUG_ON(blk_queued_rq(rq)); |
| blk_mq_add_to_requeue_list(rq, true); |
| } |
| EXPORT_SYMBOL(blk_mq_requeue_request); |
| |
| static void blk_mq_requeue_work(struct work_struct *work) |
| { |
| struct request_queue *q = |
| container_of(work, struct request_queue, requeue_work); |
| LIST_HEAD(rq_list); |
| struct request *rq, *next; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&q->requeue_lock, flags); |
| list_splice_init(&q->requeue_list, &rq_list); |
| spin_unlock_irqrestore(&q->requeue_lock, flags); |
| |
| list_for_each_entry_safe(rq, next, &rq_list, queuelist) { |
| if (!(rq->cmd_flags & REQ_SOFTBARRIER)) |
| continue; |
| |
| rq->cmd_flags &= ~REQ_SOFTBARRIER; |
| list_del_init(&rq->queuelist); |
| blk_mq_insert_request(rq, true, false, false); |
| } |
| |
| while (!list_empty(&rq_list)) { |
| rq = list_entry(rq_list.next, struct request, queuelist); |
| list_del_init(&rq->queuelist); |
| blk_mq_insert_request(rq, false, false, false); |
| } |
| |
| /* |
| * Use the start variant of queue running here, so that running |
| * the requeue work will kick stopped queues. |
| */ |
| blk_mq_start_hw_queues(q); |
| } |
| |
| void blk_mq_add_to_requeue_list(struct request *rq, bool at_head) |
| { |
| struct request_queue *q = rq->q; |
| unsigned long flags; |
| |
| /* |
| * We abuse this flag that is otherwise used by the I/O scheduler to |
| * request head insertation from the workqueue. |
| */ |
| BUG_ON(rq->cmd_flags & REQ_SOFTBARRIER); |
| |
| spin_lock_irqsave(&q->requeue_lock, flags); |
| if (at_head) { |
| rq->cmd_flags |= REQ_SOFTBARRIER; |
| list_add(&rq->queuelist, &q->requeue_list); |
| } else { |
| list_add_tail(&rq->queuelist, &q->requeue_list); |
| } |
| spin_unlock_irqrestore(&q->requeue_lock, flags); |
| } |
| EXPORT_SYMBOL(blk_mq_add_to_requeue_list); |
| |
| void blk_mq_cancel_requeue_work(struct request_queue *q) |
| { |
| cancel_work_sync(&q->requeue_work); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_cancel_requeue_work); |
| |
| void blk_mq_kick_requeue_list(struct request_queue *q) |
| { |
| kblockd_schedule_work(&q->requeue_work); |
| } |
| EXPORT_SYMBOL(blk_mq_kick_requeue_list); |
| |
| void blk_mq_abort_requeue_list(struct request_queue *q) |
| { |
| unsigned long flags; |
| LIST_HEAD(rq_list); |
| |
| spin_lock_irqsave(&q->requeue_lock, flags); |
| list_splice_init(&q->requeue_list, &rq_list); |
| spin_unlock_irqrestore(&q->requeue_lock, flags); |
| |
| while (!list_empty(&rq_list)) { |
| struct request *rq; |
| |
| rq = list_first_entry(&rq_list, struct request, queuelist); |
| list_del_init(&rq->queuelist); |
| rq->errors = -EIO; |
| blk_mq_end_request(rq, rq->errors); |
| } |
| } |
| EXPORT_SYMBOL(blk_mq_abort_requeue_list); |
| |
| struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) |
| { |
| return tags->rqs[tag]; |
| } |
| EXPORT_SYMBOL(blk_mq_tag_to_rq); |
| |
| struct blk_mq_timeout_data { |
| unsigned long next; |
| unsigned int next_set; |
| }; |
| |
| void blk_mq_rq_timed_out(struct request *req, bool reserved) |
| { |
| struct blk_mq_ops *ops = req->q->mq_ops; |
| enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER; |
| |
| /* |
| * We know that complete is set at this point. If STARTED isn't set |
| * anymore, then the request isn't active and the "timeout" should |
| * just be ignored. This can happen due to the bitflag ordering. |
| * Timeout first checks if STARTED is set, and if it is, assumes |
| * the request is active. But if we race with completion, then |
| * we both flags will get cleared. So check here again, and ignore |
| * a timeout event with a request that isn't active. |
| */ |
| if (!test_bit(REQ_ATOM_STARTED, &req->atomic_flags)) |
| return; |
| |
| if (ops->timeout) |
| ret = ops->timeout(req, reserved); |
| |
| switch (ret) { |
| case BLK_EH_HANDLED: |
| __blk_mq_complete_request(req); |
| break; |
| case BLK_EH_RESET_TIMER: |
| blk_add_timer(req); |
| blk_clear_rq_complete(req); |
| break; |
| case BLK_EH_NOT_HANDLED: |
| break; |
| default: |
| printk(KERN_ERR "block: bad eh return: %d\n", ret); |
| break; |
| } |
| } |
| |
| static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, |
| struct request *rq, void *priv, bool reserved) |
| { |
| struct blk_mq_timeout_data *data = priv; |
| |
| if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) { |
| /* |
| * If a request wasn't started before the queue was |
| * marked dying, kill it here or it'll go unnoticed. |
| */ |
| if (unlikely(blk_queue_dying(rq->q))) { |
| rq->errors = -EIO; |
| blk_mq_end_request(rq, rq->errors); |
| } |
| return; |
| } |
| if (rq->cmd_flags & REQ_NO_TIMEOUT) |
| return; |
| |
| if (time_after_eq(jiffies, rq->deadline)) { |
| if (!blk_mark_rq_complete(rq)) |
| blk_mq_rq_timed_out(rq, reserved); |
| } else if (!data->next_set || time_after(data->next, rq->deadline)) { |
| data->next = rq->deadline; |
| data->next_set = 1; |
| } |
| } |
| |
| static void blk_mq_rq_timer(unsigned long priv) |
| { |
| struct request_queue *q = (struct request_queue *)priv; |
| struct blk_mq_timeout_data data = { |
| .next = 0, |
| .next_set = 0, |
| }; |
| int i; |
| |
| blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data); |
| |
| if (data.next_set) { |
| data.next = blk_rq_timeout(round_jiffies_up(data.next)); |
| mod_timer(&q->timeout, data.next); |
| } else { |
| struct blk_mq_hw_ctx *hctx; |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| /* the hctx may be unmapped, so check it here */ |
| if (blk_mq_hw_queue_mapped(hctx)) |
| blk_mq_tag_idle(hctx); |
| } |
| } |
| } |
| |
| /* |
| * 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; |
| } |
| |
| /* |
| * Process software queues that have been marked busy, splicing them |
| * to the for-dispatch |
| */ |
| static void flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list) |
| { |
| struct blk_mq_ctx *ctx; |
| int i; |
| |
| for (i = 0; i < hctx->ctx_map.size; i++) { |
| struct blk_align_bitmap *bm = &hctx->ctx_map.map[i]; |
| unsigned int off, bit; |
| |
| if (!bm->word) |
| continue; |
| |
| bit = 0; |
| off = i * hctx->ctx_map.bits_per_word; |
| do { |
| bit = find_next_bit(&bm->word, bm->depth, bit); |
| if (bit >= bm->depth) |
| break; |
| |
| ctx = hctx->ctxs[bit + off]; |
| clear_bit(bit, &bm->word); |
| spin_lock(&ctx->lock); |
| list_splice_tail_init(&ctx->rq_list, list); |
| spin_unlock(&ctx->lock); |
| |
| bit++; |
| } while (1); |
| } |
| } |
| |
| /* |
| * 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 request *rq; |
| LIST_HEAD(rq_list); |
| LIST_HEAD(driver_list); |
| struct list_head *dptr; |
| int queued; |
| |
| WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)); |
| |
| if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state))) |
| return; |
| |
| hctx->run++; |
| |
| /* |
| * Touch any software queue that has pending entries. |
| */ |
| flush_busy_ctxs(hctx, &rq_list); |
| |
| /* |
| * 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); |
| } |
| |
| /* |
| * Start off with dptr being NULL, so we start the first request |
| * immediately, even if we have more pending. |
| */ |
| dptr = NULL; |
| |
| /* |
| * Now process all the entries, sending them to the driver. |
| */ |
| queued = 0; |
| while (!list_empty(&rq_list)) { |
| struct blk_mq_queue_data bd; |
| int ret; |
| |
| rq = list_first_entry(&rq_list, struct request, queuelist); |
| list_del_init(&rq->queuelist); |
| |
| bd.rq = rq; |
| bd.list = dptr; |
| bd.last = list_empty(&rq_list); |
| |
| ret = q->mq_ops->queue_rq(hctx, &bd); |
| switch (ret) { |
| case BLK_MQ_RQ_QUEUE_OK: |
| queued++; |
| break; |
| case BLK_MQ_RQ_QUEUE_BUSY: |
| list_add(&rq->queuelist, &rq_list); |
| __blk_mq_requeue_request(rq); |
| break; |
| default: |
| pr_err("blk-mq: bad return on queue: %d\n", ret); |
| case BLK_MQ_RQ_QUEUE_ERROR: |
| rq->errors = -EIO; |
| blk_mq_end_request(rq, rq->errors); |
| break; |
| } |
| |
| if (ret == BLK_MQ_RQ_QUEUE_BUSY) |
| break; |
| |
| /* |
| * We've done the first request. If we have more than 1 |
| * left in the list, set dptr to defer issue. |
| */ |
| if (!dptr && rq_list.next != rq_list.prev) |
| dptr = &driver_list; |
| } |
| |
| 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); |
| /* |
| * the queue is expected stopped with BLK_MQ_RQ_QUEUE_BUSY, but |
| * it's possible the queue is stopped and restarted again |
| * before this. Queue restart will dispatch requests. And since |
| * requests in rq_list aren't added into hctx->dispatch yet, |
| * the requests in rq_list might get lost. |
| * |
| * blk_mq_run_hw_queue() already checks the STOPPED bit |
| **/ |
| blk_mq_run_hw_queue(hctx, true); |
| } |
| } |
| |
| /* |
| * It'd be great if the workqueue API had a way to pass |
| * in a mask and had some smarts for more clever placement. |
| * For now we just round-robin here, switching for every |
| * BLK_MQ_CPU_WORK_BATCH queued items. |
| */ |
| static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) |
| { |
| if (hctx->queue->nr_hw_queues == 1) |
| return WORK_CPU_UNBOUND; |
| |
| if (--hctx->next_cpu_batch <= 0) { |
| int cpu = hctx->next_cpu, next_cpu; |
| |
| next_cpu = cpumask_next(hctx->next_cpu, hctx->cpumask); |
| if (next_cpu >= nr_cpu_ids) |
| next_cpu = cpumask_first(hctx->cpumask); |
| |
| hctx->next_cpu = next_cpu; |
| hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; |
| |
| return cpu; |
| } |
| |
| return hctx->next_cpu; |
| } |
| |
| void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) |
| { |
| if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state) || |
| !blk_mq_hw_queue_mapped(hctx))) |
| return; |
| |
| if (!async) { |
| int cpu = get_cpu(); |
| if (cpumask_test_cpu(cpu, hctx->cpumask)) { |
| __blk_mq_run_hw_queue(hctx); |
| put_cpu(); |
| return; |
| } |
| |
| put_cpu(); |
| } |
| |
| kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx), |
| &hctx->run_work, 0); |
| } |
| |
| void blk_mq_run_hw_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->state)) |
| continue; |
| |
| blk_mq_run_hw_queue(hctx, async); |
| } |
| } |
| EXPORT_SYMBOL(blk_mq_run_hw_queues); |
| |
| void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) |
| { |
| cancel_delayed_work(&hctx->run_work); |
| cancel_delayed_work(&hctx->delay_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, false); |
| } |
| EXPORT_SYMBOL(blk_mq_start_hw_queue); |
| |
| void blk_mq_start_hw_queues(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| blk_mq_start_hw_queue(hctx); |
| } |
| EXPORT_SYMBOL(blk_mq_start_hw_queues); |
| |
| void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async) |
| { |
| 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, async); |
| } |
| } |
| EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); |
| |
| static void blk_mq_run_work_fn(struct work_struct *work) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| |
| hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work); |
| |
| __blk_mq_run_hw_queue(hctx); |
| } |
| |
| static void blk_mq_delay_work_fn(struct work_struct *work) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| |
| hctx = container_of(work, struct blk_mq_hw_ctx, delay_work.work); |
| |
| if (test_and_clear_bit(BLK_MQ_S_STOPPED, &hctx->state)) |
| __blk_mq_run_hw_queue(hctx); |
| } |
| |
| void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) |
| { |
| if (unlikely(!blk_mq_hw_queue_mapped(hctx))) |
| return; |
| |
| kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx), |
| &hctx->delay_work, msecs_to_jiffies(msecs)); |
| } |
| EXPORT_SYMBOL(blk_mq_delay_queue); |
| |
| static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx, |
| struct blk_mq_ctx *ctx, |
| struct request *rq, |
| bool at_head) |
| { |
| trace_block_rq_insert(hctx->queue, rq); |
| |
| if (at_head) |
| list_add(&rq->queuelist, &ctx->rq_list); |
| else |
| list_add_tail(&rq->queuelist, &ctx->rq_list); |
| } |
| |
| static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, |
| struct request *rq, bool at_head) |
| { |
| struct blk_mq_ctx *ctx = rq->mq_ctx; |
| |
| __blk_mq_insert_req_list(hctx, ctx, rq, at_head); |
| blk_mq_hctx_mark_pending(hctx, ctx); |
| } |
| |
| void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue, |
| bool async) |
| { |
| struct request_queue *q = rq->q; |
| struct blk_mq_hw_ctx *hctx; |
| struct blk_mq_ctx *ctx = rq->mq_ctx, *current_ctx; |
| |
| current_ctx = blk_mq_get_ctx(q); |
| if (!cpu_online(ctx->cpu)) |
| rq->mq_ctx = ctx = current_ctx; |
| |
| hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| |
| spin_lock(&ctx->lock); |
| __blk_mq_insert_request(hctx, rq, at_head); |
| spin_unlock(&ctx->lock); |
| |
| if (run_queue) |
| blk_mq_run_hw_queue(hctx, async); |
| |
| blk_mq_put_ctx(current_ctx); |
| } |
| |
| 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_req_list(hctx, ctx, rq, false); |
| } |
| blk_mq_hctx_mark_pending(hctx, ctx); |
| spin_unlock(&ctx->lock); |
| |
| blk_mq_run_hw_queue(hctx, from_schedule); |
| blk_mq_put_ctx(current_ctx); |
| } |
| |
| 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); |
| |
| if (blk_do_io_stat(rq)) |
| blk_account_io_start(rq, 1); |
| } |
| |
| static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx) |
| { |
| return (hctx->flags & BLK_MQ_F_SHOULD_MERGE) && |
| !blk_queue_nomerges(hctx->queue); |
| } |
| |
| static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx, |
| struct blk_mq_ctx *ctx, |
| struct request *rq, struct bio *bio) |
| { |
| if (!hctx_allow_merges(hctx) || !bio_mergeable(bio)) { |
| blk_mq_bio_to_request(rq, bio); |
| spin_lock(&ctx->lock); |
| insert_rq: |
| __blk_mq_insert_request(hctx, rq, false); |
| spin_unlock(&ctx->lock); |
| return false; |
| } else { |
| struct request_queue *q = hctx->queue; |
| |
| spin_lock(&ctx->lock); |
| if (!blk_mq_attempt_merge(q, ctx, bio)) { |
| blk_mq_bio_to_request(rq, bio); |
| goto insert_rq; |
| } |
| |
| spin_unlock(&ctx->lock); |
| __blk_mq_free_request(hctx, ctx, rq); |
| return true; |
| } |
| } |
| |
| struct blk_map_ctx { |
| struct blk_mq_hw_ctx *hctx; |
| struct blk_mq_ctx *ctx; |
| }; |
| |
| static struct request *blk_mq_map_request(struct request_queue *q, |
| struct bio *bio, |
| struct blk_map_ctx *data) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| struct blk_mq_ctx *ctx; |
| struct request *rq; |
| int rw = bio_data_dir(bio); |
| struct blk_mq_alloc_data alloc_data; |
| |
| blk_queue_enter_live(q); |
| ctx = blk_mq_get_ctx(q); |
| hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| |
| if (rw_is_sync(bio->bi_rw)) |
| rw |= REQ_SYNC; |
| |
| trace_block_getrq(q, bio, rw); |
| blk_mq_set_alloc_data(&alloc_data, q, GFP_ATOMIC, false, ctx, |
| hctx); |
| rq = __blk_mq_alloc_request(&alloc_data, rw); |
| if (unlikely(!rq)) { |
| __blk_mq_run_hw_queue(hctx); |
| blk_mq_put_ctx(ctx); |
| trace_block_sleeprq(q, bio, rw); |
| |
| ctx = blk_mq_get_ctx(q); |
| hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| blk_mq_set_alloc_data(&alloc_data, q, |
| __GFP_RECLAIM|__GFP_HIGH, false, ctx, hctx); |
| rq = __blk_mq_alloc_request(&alloc_data, rw); |
| ctx = alloc_data.ctx; |
| hctx = alloc_data.hctx; |
| } |
| |
| hctx->queued++; |
| data->hctx = hctx; |
| data->ctx = ctx; |
| return rq; |
| } |
| |
| static int blk_mq_direct_issue_request(struct request *rq, blk_qc_t *cookie) |
| { |
| int ret; |
| struct request_queue *q = rq->q; |
| struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, |
| rq->mq_ctx->cpu); |
| struct blk_mq_queue_data bd = { |
| .rq = rq, |
| .list = NULL, |
| .last = 1 |
| }; |
| blk_qc_t new_cookie = blk_tag_to_qc_t(rq->tag, hctx->queue_num); |
| |
| /* |
| * For OK queue, we are done. For error, kill it. Any other |
| * error (busy), just add it to our list as we previously |
| * would have done |
| */ |
| ret = q->mq_ops->queue_rq(hctx, &bd); |
| if (ret == BLK_MQ_RQ_QUEUE_OK) { |
| *cookie = new_cookie; |
| return 0; |
| } |
| |
| __blk_mq_requeue_request(rq); |
| |
| if (ret == BLK_MQ_RQ_QUEUE_ERROR) { |
| *cookie = BLK_QC_T_NONE; |
| rq->errors = -EIO; |
| blk_mq_end_request(rq, rq->errors); |
| return 0; |
| } |
| |
| return -1; |
| } |
| |
| /* |
| * Multiple hardware queue variant. This will not use per-process plugs, |
| * but will attempt to bypass the hctx queueing if we can go straight to |
| * hardware for SYNC IO. |
| */ |
| static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) |
| { |
| const int is_sync = rw_is_sync(bio->bi_rw); |
| const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA); |
| struct blk_map_ctx data; |
| struct request *rq; |
| unsigned int request_count = 0; |
| struct blk_plug *plug; |
| struct request *same_queue_rq = NULL; |
| blk_qc_t cookie; |
| |
| blk_queue_bounce(q, &bio); |
| |
| if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { |
| bio_io_error(bio); |
| return BLK_QC_T_NONE; |
| } |
| |
| blk_queue_split(q, &bio, q->bio_split); |
| |
| if (!is_flush_fua && !blk_queue_nomerges(q)) { |
| if (blk_attempt_plug_merge(q, bio, &request_count, |
| &same_queue_rq)) |
| return BLK_QC_T_NONE; |
| } else |
| request_count = blk_plug_queued_count(q); |
| |
| rq = blk_mq_map_request(q, bio, &data); |
| if (unlikely(!rq)) |
| return BLK_QC_T_NONE; |
| |
| cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num); |
| |
| if (unlikely(is_flush_fua)) { |
| blk_mq_bio_to_request(rq, bio); |
| blk_insert_flush(rq); |
| goto run_queue; |
| } |
| |
| plug = current->plug; |
| /* |
| * If the driver supports defer issued based on 'last', then |
| * queue it up like normal since we can potentially save some |
| * CPU this way. |
| */ |
| if (((plug && !blk_queue_nomerges(q)) || is_sync) && |
| !(data.hctx->flags & BLK_MQ_F_DEFER_ISSUE)) { |
| struct request *old_rq = NULL; |
| |
| blk_mq_bio_to_request(rq, bio); |
| |
| /* |
| * We do limited pluging. If the bio can be merged, do that. |
| * Otherwise the existing request in the plug list will be |
| * issued. So the plug list will have one request at most |
| */ |
| if (plug) { |
| /* |
| * The plug list might get flushed before this. If that |
| * happens, same_queue_rq is invalid and plug list is |
| * empty |
| */ |
| if (same_queue_rq && !list_empty(&plug->mq_list)) { |
| old_rq = same_queue_rq; |
| list_del_init(&old_rq->queuelist); |
| } |
| list_add_tail(&rq->queuelist, &plug->mq_list); |
| } else /* is_sync */ |
| old_rq = rq; |
| blk_mq_put_ctx(data.ctx); |
| if (!old_rq) |
| goto done; |
| if (test_bit(BLK_MQ_S_STOPPED, &data.hctx->state) || |
| blk_mq_direct_issue_request(old_rq, &cookie) != 0) |
| blk_mq_insert_request(old_rq, false, true, true); |
| goto done; |
| } |
| |
| if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) { |
| /* |
| * 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(data.hctx, !is_sync || is_flush_fua); |
| } |
| blk_mq_put_ctx(data.ctx); |
| done: |
| return cookie; |
| } |
| |
| /* |
| * Single hardware queue variant. This will attempt to use any per-process |
| * plug for merging and IO deferral. |
| */ |
| static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio) |
| { |
| const int is_sync = rw_is_sync(bio->bi_rw); |
| const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA); |
| struct blk_plug *plug; |
| unsigned int request_count = 0; |
| struct blk_map_ctx data; |
| struct request *rq; |
| blk_qc_t cookie; |
| |
| blk_queue_bounce(q, &bio); |
| |
| if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { |
| bio_io_error(bio); |
| return BLK_QC_T_NONE; |
| } |
| |
| blk_queue_split(q, &bio, q->bio_split); |
| |
| if (!is_flush_fua && !blk_queue_nomerges(q) && |
| blk_attempt_plug_merge(q, bio, &request_count, NULL)) |
| return BLK_QC_T_NONE; |
| |
| rq = blk_mq_map_request(q, bio, &data); |
| if (unlikely(!rq)) |
| return BLK_QC_T_NONE; |
| |
| cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num); |
| |
| if (unlikely(is_flush_fua)) { |
| blk_mq_bio_to_request(rq, bio); |
| 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. |
| */ |
| plug = current->plug; |
| if (plug) { |
| blk_mq_bio_to_request(rq, bio); |
| if (!request_count) |
| trace_block_plug(q); |
| |
| blk_mq_put_ctx(data.ctx); |
| |
| 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); |
| return cookie; |
| } |
| |
| if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) { |
| /* |
| * 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(data.hctx, !is_sync || is_flush_fua); |
| } |
| |
| blk_mq_put_ctx(data.ctx); |
| return cookie; |
| } |
| |
| /* |
| * 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); |
| |
| static void blk_mq_free_rq_map(struct blk_mq_tag_set *set, |
| struct blk_mq_tags *tags, unsigned int hctx_idx) |
| { |
| struct page *page; |
| |
| if (tags->rqs && set->ops->exit_request) { |
| int i; |
| |
| for (i = 0; i < tags->nr_tags; i++) { |
| if (!tags->rqs[i]) |
| continue; |
| set->ops->exit_request(set->driver_data, tags->rqs[i], |
| hctx_idx, i); |
| tags->rqs[i] = NULL; |
| } |
| } |
| |
| while (!list_empty(&tags->page_list)) { |
| page = list_first_entry(&tags->page_list, struct page, lru); |
| list_del_init(&page->lru); |
| /* |
| * Remove kmemleak object previously allocated in |
| * blk_mq_init_rq_map(). |
| */ |
| kmemleak_free(page_address(page)); |
| __free_pages(page, page->private); |
| } |
| |
| kfree(tags->rqs); |
| |
| blk_mq_free_tags(tags); |
| } |
| |
| static size_t order_to_size(unsigned int order) |
| { |
| return (size_t)PAGE_SIZE << order; |
| } |
| |
| static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set, |
| unsigned int hctx_idx) |
| { |
| struct blk_mq_tags *tags; |
| unsigned int i, j, entries_per_page, max_order = 4; |
| size_t rq_size, left; |
| |
| tags = blk_mq_init_tags(set->queue_depth, set->reserved_tags, |
| set->numa_node, |
| BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags)); |
| if (!tags) |
| return NULL; |
| |
| INIT_LIST_HEAD(&tags->page_list); |
| |
| tags->rqs = kzalloc_node(set->queue_depth * sizeof(struct request *), |
| GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY, |
| set->numa_node); |
| if (!tags->rqs) { |
| blk_mq_free_tags(tags); |
| return NULL; |
| } |
| |
| /* |
| * rq_size is the size of the request plus driver payload, rounded |
| * to the cacheline size |
| */ |
| rq_size = round_up(sizeof(struct request) + set->cmd_size, |
| cache_line_size()); |
| left = rq_size * set->queue_depth; |
| |
| for (i = 0; i < set->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(set->numa_node, |
| GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO, |
| this_order); |
| if (page) |
| break; |
| if (!this_order--) |
| break; |
| if (order_to_size(this_order) < rq_size) |
| break; |
| } while (1); |
| |
| if (!page) |
| goto fail; |
| |
| page->private = this_order; |
| list_add_tail(&page->lru, &tags->page_list); |
| |
| p = page_address(page); |
| /* |
| * Allow kmemleak to scan these pages as they contain pointers |
| * to additional allocations like via ops->init_request(). |
| */ |
| kmemleak_alloc(p, order_to_size(this_order), 1, GFP_KERNEL); |
| entries_per_page = order_to_size(this_order) / rq_size; |
| to_do = min(entries_per_page, set->queue_depth - i); |
| left -= to_do * rq_size; |
| for (j = 0; j < to_do; j++) { |
| tags->rqs[i] = p; |
| if (set->ops->init_request) { |
| if (set->ops->init_request(set->driver_data, |
| tags->rqs[i], hctx_idx, i, |
| set->numa_node)) { |
| tags->rqs[i] = NULL; |
| goto fail; |
| } |
| } |
| |
| p += rq_size; |
| i++; |
| } |
| } |
| return tags; |
| |
| fail: |
| blk_mq_free_rq_map(set, tags, hctx_idx); |
| return NULL; |
| } |
| |
| static void blk_mq_free_bitmap(struct blk_mq_ctxmap *bitmap) |
| { |
| kfree(bitmap->map); |
| } |
| |
| static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap *bitmap, int node) |
| { |
| unsigned int bpw = 8, total, num_maps, i; |
| |
| bitmap->bits_per_word = bpw; |
| |
| num_maps = ALIGN(nr_cpu_ids, bpw) / bpw; |
| bitmap->map = kzalloc_node(num_maps * sizeof(struct blk_align_bitmap), |
| GFP_KERNEL, node); |
| if (!bitmap->map) |
| return -ENOMEM; |
| |
| total = nr_cpu_ids; |
| for (i = 0; i < num_maps; i++) { |
| bitmap->map[i].depth = min(total, bitmap->bits_per_word); |
| total -= bitmap->map[i].depth; |
| } |
| |
| return 0; |
| } |
| |
| static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx *hctx, int cpu) |
| { |
| struct request_queue *q = hctx->queue; |
| struct blk_mq_ctx *ctx; |
| LIST_HEAD(tmp); |
| |
| /* |
| * Move ctx entries to new CPU, if this one is going away. |
| */ |
| ctx = __blk_mq_get_ctx(q, cpu); |
| |
| spin_lock(&ctx->lock); |
| if (!list_empty(&ctx->rq_list)) { |
| list_splice_init(&ctx->rq_list, &tmp); |
| blk_mq_hctx_clear_pending(hctx, ctx); |
| } |
| spin_unlock(&ctx->lock); |
| |
| if (list_empty(&tmp)) |
| return NOTIFY_OK; |
| |
| ctx = blk_mq_get_ctx(q); |
| 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); |
| } |
| |
| hctx = q->mq_ops->map_queue(q, ctx->cpu); |
| blk_mq_hctx_mark_pending(hctx, ctx); |
| |
| spin_unlock(&ctx->lock); |
| |
| blk_mq_run_hw_queue(hctx, true); |
| blk_mq_put_ctx(ctx); |
| return NOTIFY_OK; |
| } |
| |
| static int blk_mq_hctx_notify(void *data, unsigned long action, |
| unsigned int cpu) |
| { |
| struct blk_mq_hw_ctx *hctx = data; |
| |
| if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) |
| return blk_mq_hctx_cpu_offline(hctx, cpu); |
| |
| /* |
| * In case of CPU online, tags may be reallocated |
| * in blk_mq_map_swqueue() after mapping is updated. |
| */ |
| |
| return NOTIFY_OK; |
| } |
| |
| /* hctx->ctxs will be freed in queue's release handler */ |
| static void blk_mq_exit_hctx(struct request_queue *q, |
| struct blk_mq_tag_set *set, |
| struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) |
| { |
| unsigned flush_start_tag = set->queue_depth; |
| |
| blk_mq_tag_idle(hctx); |
| |
| if (set->ops->exit_request) |
| set->ops->exit_request(set->driver_data, |
| hctx->fq->flush_rq, hctx_idx, |
| flush_start_tag + hctx_idx); |
| |
| if (set->ops->exit_hctx) |
| set->ops->exit_hctx(hctx, hctx_idx); |
| |
| blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); |
| blk_free_flush_queue(hctx->fq); |
| blk_mq_free_bitmap(&hctx->ctx_map); |
| } |
| |
| static void blk_mq_exit_hw_queues(struct request_queue *q, |
| struct blk_mq_tag_set *set, int nr_queue) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (i == nr_queue) |
| break; |
| blk_mq_exit_hctx(q, set, hctx, i); |
| } |
| } |
| |
| static void blk_mq_free_hw_queues(struct request_queue *q, |
| struct blk_mq_tag_set *set) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| free_cpumask_var(hctx->cpumask); |
| } |
| |
| static int blk_mq_init_hctx(struct request_queue *q, |
| struct blk_mq_tag_set *set, |
| struct blk_mq_hw_ctx *hctx, unsigned hctx_idx) |
| { |
| int node; |
| unsigned flush_start_tag = set->queue_depth; |
| |
| node = hctx->numa_node; |
| if (node == NUMA_NO_NODE) |
| node = hctx->numa_node = set->numa_node; |
| |
| INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn); |
| INIT_DELAYED_WORK(&hctx->delay_work, blk_mq_delay_work_fn); |
| spin_lock_init(&hctx->lock); |
| INIT_LIST_HEAD(&hctx->dispatch); |
| hctx->queue = q; |
| hctx->queue_num = hctx_idx; |
| hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED; |
| |
| blk_mq_init_cpu_notifier(&hctx->cpu_notifier, |
| blk_mq_hctx_notify, hctx); |
| blk_mq_register_cpu_notifier(&hctx->cpu_notifier); |
| |
| hctx->tags = set->tags[hctx_idx]; |
| |
| /* |
| * Allocate space for all possible cpus to avoid allocation at |
| * runtime |
| */ |
| hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *), |
| GFP_KERNEL, node); |
| if (!hctx->ctxs) |
| goto unregister_cpu_notifier; |
| |
| if (blk_mq_alloc_bitmap(&hctx->ctx_map, node)) |
| goto free_ctxs; |
| |
| hctx->nr_ctx = 0; |
| |
| if (set->ops->init_hctx && |
| set->ops->init_hctx(hctx, set->driver_data, hctx_idx)) |
| goto free_bitmap; |
| |
| hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size); |
| if (!hctx->fq) |
| goto exit_hctx; |
| |
| if (set->ops->init_request && |
| set->ops->init_request(set->driver_data, |
| hctx->fq->flush_rq, hctx_idx, |
| flush_start_tag + hctx_idx, node)) |
| goto free_fq; |
| |
| return 0; |
| |
| free_fq: |
| kfree(hctx->fq); |
| exit_hctx: |
| if (set->ops->exit_hctx) |
| set->ops->exit_hctx(hctx, hctx_idx); |
| free_bitmap: |
| blk_mq_free_bitmap(&hctx->ctx_map); |
| free_ctxs: |
| kfree(hctx->ctxs); |
| unregister_cpu_notifier: |
| blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); |
| |
| return -1; |
| } |
| |
| static int blk_mq_init_hw_queues(struct request_queue *q, |
| struct blk_mq_tag_set *set) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned int i; |
| |
| /* |
| * Initialize hardware queues |
| */ |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (blk_mq_init_hctx(q, set, hctx, i)) |
| break; |
| } |
| |
| if (i == q->nr_hw_queues) |
| return 0; |
| |
| /* |
| * Init failed |
| */ |
| blk_mq_exit_hw_queues(q, set, i); |
| |
| 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 */ |
| if (!cpu_online(i)) |
| continue; |
| |
| hctx = q->mq_ops->map_queue(q, i); |
| |
| /* |
| * 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, |
| const struct cpumask *online_mask) |
| { |
| unsigned int i; |
| struct blk_mq_hw_ctx *hctx; |
| struct blk_mq_ctx *ctx; |
| struct blk_mq_tag_set *set = q->tag_set; |
| |
| /* |
| * Avoid others reading imcomplete hctx->cpumask through sysfs |
| */ |
| mutex_lock(&q->sysfs_lock); |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| cpumask_clear(hctx->cpumask); |
| 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 */ |
| if (!cpumask_test_cpu(i, online_mask)) |
| continue; |
| |
| hctx = q->mq_ops->map_queue(q, i); |
| cpumask_set_cpu(i, hctx->cpumask); |
| ctx->index_hw = hctx->nr_ctx; |
| hctx->ctxs[hctx->nr_ctx++] = ctx; |
| } |
| |
| mutex_unlock(&q->sysfs_lock); |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| struct blk_mq_ctxmap *map = &hctx->ctx_map; |
| |
| /* |
| * If no software queues are mapped to this hardware queue, |
| * disable it and free the request entries. |
| */ |
| if (!hctx->nr_ctx) { |
| if (set->tags[i]) { |
| blk_mq_free_rq_map(set, set->tags[i], i); |
| set->tags[i] = NULL; |
| } |
| hctx->tags = NULL; |
| continue; |
| } |
| |
| /* unmapped hw queue can be remapped after CPU topo changed */ |
| if (!set->tags[i]) |
| set->tags[i] = blk_mq_init_rq_map(set, i); |
| hctx->tags = set->tags[i]; |
| WARN_ON(!hctx->tags); |
| |
| /* |
| * Set the map size to the number of mapped software queues. |
| * This is more accurate and more efficient than looping |
| * over all possibly mapped software queues. |
| */ |
| map->size = DIV_ROUND_UP(hctx->nr_ctx, map->bits_per_word); |
| |
| /* |
| * Initialize batch roundrobin counts |
| */ |
| hctx->next_cpu = cpumask_first(hctx->cpumask); |
| hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; |
| } |
| |
| queue_for_each_ctx(q, ctx, i) { |
| if (!cpumask_test_cpu(i, online_mask)) |
| continue; |
| |
| hctx = q->mq_ops->map_queue(q, i); |
| cpumask_set_cpu(i, hctx->tags->cpumask); |
| } |
| } |
| |
| static void queue_set_hctx_shared(struct request_queue *q, bool shared) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (shared) |
| hctx->flags |= BLK_MQ_F_TAG_SHARED; |
| else |
| hctx->flags &= ~BLK_MQ_F_TAG_SHARED; |
| } |
| } |
| |
| static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set, bool shared) |
| { |
| struct request_queue *q; |
| |
| list_for_each_entry(q, &set->tag_list, tag_set_list) { |
| blk_mq_freeze_queue(q); |
| queue_set_hctx_shared(q, shared); |
| blk_mq_unfreeze_queue(q); |
| } |
| } |
| |
| static void blk_mq_del_queue_tag_set(struct request_queue *q) |
| { |
| struct blk_mq_tag_set *set = q->tag_set; |
| |
| mutex_lock(&set->tag_list_lock); |
| list_del_init(&q->tag_set_list); |
| if (list_is_singular(&set->tag_list)) { |
| /* just transitioned to unshared */ |
| set->flags &= ~BLK_MQ_F_TAG_SHARED; |
| /* update existing queue */ |
| blk_mq_update_tag_set_depth(set, false); |
| } |
| mutex_unlock(&set->tag_list_lock); |
| } |
| |
| static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, |
| struct request_queue *q) |
| { |
| q->tag_set = set; |
| |
| mutex_lock(&set->tag_list_lock); |
| |
| /* Check to see if we're transitioning to shared (from 1 to 2 queues). */ |
| if (!list_empty(&set->tag_list) && !(set->flags & BLK_MQ_F_TAG_SHARED)) { |
| set->flags |= BLK_MQ_F_TAG_SHARED; |
| /* update existing queue */ |
| blk_mq_update_tag_set_depth(set, true); |
| } |
| if (set->flags & BLK_MQ_F_TAG_SHARED) |
| queue_set_hctx_shared(q, true); |
| list_add_tail(&q->tag_set_list, &set->tag_list); |
| |
| mutex_unlock(&set->tag_list_lock); |
| } |
| |
| /* |
| * It is the actual release handler for mq, but we do it from |
| * request queue's release handler for avoiding use-after-free |
| * and headache because q->mq_kobj shouldn't have been introduced, |
| * but we can't group ctx/kctx kobj without it. |
| */ |
| void blk_mq_release(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned int i; |
| |
| /* hctx kobj stays in hctx */ |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (!hctx) |
| continue; |
| kfree(hctx->ctxs); |
| kfree(hctx); |
| } |
| |
| kfree(q->mq_map); |
| q->mq_map = NULL; |
| |
| kfree(q->queue_hw_ctx); |
| |
| /* ctx kobj stays in queue_ctx */ |
| free_percpu(q->queue_ctx); |
| } |
| |
| struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set) |
| { |
| struct request_queue *uninit_q, *q; |
| |
| uninit_q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node); |
| if (!uninit_q) |
| return ERR_PTR(-ENOMEM); |
| |
| q = blk_mq_init_allocated_queue(set, uninit_q); |
| if (IS_ERR(q)) |
| blk_cleanup_queue(uninit_q); |
| |
| return q; |
| } |
| EXPORT_SYMBOL(blk_mq_init_queue); |
| |
| struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, |
| struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx **hctxs; |
| struct blk_mq_ctx __percpu *ctx; |
| unsigned int *map; |
| int i; |
| |
| ctx = alloc_percpu(struct blk_mq_ctx); |
| if (!ctx) |
| return ERR_PTR(-ENOMEM); |
| |
| hctxs = kmalloc_node(set->nr_hw_queues * sizeof(*hctxs), GFP_KERNEL, |
| set->numa_node); |
| |
| if (!hctxs) |
| goto err_percpu; |
| |
| map = blk_mq_make_queue_map(set); |
| if (!map) |
| goto err_map; |
| |
| for (i = 0; i < set->nr_hw_queues; i++) { |
| int node = blk_mq_hw_queue_to_node(map, i); |
| |
| hctxs[i] = kzalloc_node(sizeof(struct blk_mq_hw_ctx), |
| GFP_KERNEL, node); |
| if (!hctxs[i]) |
| goto err_hctxs; |
| |
| if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask, GFP_KERNEL, |
| node)) |
| goto err_hctxs; |
| |
| atomic_set(&hctxs[i]->nr_active, 0); |
| hctxs[i]->numa_node = node; |
| hctxs[i]->queue_num = i; |
| } |
| |
| setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q); |
| blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ); |
| |
| q->nr_queues = nr_cpu_ids; |
| q->nr_hw_queues = set->nr_hw_queues; |
| q->mq_map = map; |
| |
| q->queue_ctx = ctx; |
| q->queue_hw_ctx = hctxs; |
| |
| q->mq_ops = set->ops; |
| q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; |
| |
| if (!(set->flags & BLK_MQ_F_SG_MERGE)) |
| q->queue_flags |= 1 << QUEUE_FLAG_NO_SG_MERGE; |
| |
| q->sg_reserved_size = INT_MAX; |
| |
| INIT_WORK(&q->requeue_work, blk_mq_requeue_work); |
| INIT_LIST_HEAD(&q->requeue_list); |
| spin_lock_init(&q->requeue_lock); |
| |
| if (q->nr_hw_queues > 1) |
| blk_queue_make_request(q, blk_mq_make_request); |
| else |
| blk_queue_make_request(q, blk_sq_make_request); |
| |
| /* |
| * Do this after blk_queue_make_request() overrides it... |
| */ |
| q->nr_requests = set->queue_depth; |
| |
| if (set->ops->complete) |
| blk_queue_softirq_done(q, set->ops->complete); |
| |
| blk_mq_init_cpu_queues(q, set->nr_hw_queues); |
| |
| if (blk_mq_init_hw_queues(q, set)) |
| goto err_hctxs; |
| |
| get_online_cpus(); |
| mutex_lock(&all_q_mutex); |
| |
| list_add_tail(&q->all_q_node, &all_q_list); |
| blk_mq_add_queue_tag_set(set, q); |
| blk_mq_map_swqueue(q, cpu_online_mask); |
| |
| mutex_unlock(&all_q_mutex); |
| put_online_cpus(); |
| |
| return q; |
| |
| err_hctxs: |
| kfree(map); |
| for (i = 0; i < set->nr_hw_queues; i++) { |
| if (!hctxs[i]) |
| break; |
| free_cpumask_var(hctxs[i]->cpumask); |
| kfree(hctxs[i]); |
| } |
| err_map: |
| kfree(hctxs); |
| err_percpu: |
| free_percpu(ctx); |
| return ERR_PTR(-ENOMEM); |
| } |
| EXPORT_SYMBOL(blk_mq_init_allocated_queue); |
| |
| void blk_mq_free_queue(struct request_queue *q) |
| { |
| struct blk_mq_tag_set *set = q->tag_set; |
| |
| mutex_lock(&all_q_mutex); |
| list_del_init(&q->all_q_node); |
| mutex_unlock(&all_q_mutex); |
| |
| blk_mq_del_queue_tag_set(q); |
| |
| blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); |
| blk_mq_free_hw_queues(q, set); |
| } |
| |
| /* Basically redo blk_mq_init_queue with queue frozen */ |
| static void blk_mq_queue_reinit(struct request_queue *q, |
| const struct cpumask *online_mask) |
| { |
| WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth)); |
| |
| blk_mq_sysfs_unregister(q); |
| |
| blk_mq_update_queue_map(q->mq_map, q->nr_hw_queues, online_mask); |
| |
| /* |
| * 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, online_mask); |
| |
| blk_mq_sysfs_register(q); |
| } |
| |
| static int blk_mq_queue_reinit_notify(struct notifier_block *nb, |
| unsigned long action, void *hcpu) |
| { |
| struct request_queue *q; |
| int cpu = (unsigned long)hcpu; |
| /* |
| * New online cpumask which is going to be set in this hotplug event. |
| * Declare this cpumasks as global as cpu-hotplug operation is invoked |
| * one-by-one and dynamically allocating this could result in a failure. |
| */ |
| static struct cpumask online_new; |
| |
| /* |
| * Before hotadded cpu starts handling requests, new mappings must |
| * be established. Otherwise, these requests in hw queue might |
| * never be dispatched. |
| * |
| * For example, there is a single hw queue (hctx) and two CPU queues |
| * (ctx0 for CPU0, and ctx1 for CPU1). |
| * |
| * Now CPU1 is just onlined and a request is inserted into |
| * ctx1->rq_list and set bit0 in pending bitmap as ctx1->index_hw is |
| * still zero. |
| * |
| * And then while running hw queue, flush_busy_ctxs() finds bit0 is |
| * set in pending bitmap and tries to retrieve requests in |
| * hctx->ctxs[0]->rq_list. But htx->ctxs[0] is a pointer to ctx0, |
| * so the request in ctx1->rq_list is ignored. |
| */ |
| switch (action & ~CPU_TASKS_FROZEN) { |
| case CPU_DEAD: |
| case CPU_UP_CANCELED: |
| cpumask_copy(&online_new, cpu_online_mask); |
| break; |
| case CPU_UP_PREPARE: |
| cpumask_copy(&online_new, cpu_online_mask); |
| cpumask_set_cpu(cpu, &online_new); |
| break; |
| default: |
| return NOTIFY_OK; |
| } |
| |
| mutex_lock(&all_q_mutex); |
| |
| /* |
| * We need to freeze and reinit all existing queues. Freezing |
| * involves synchronous wait for an RCU grace period and doing it |
| * one by one may take a long time. Start freezing all queues in |
| * one swoop and then wait for the completions so that freezing can |
| * take place in parallel. |
| */ |
| list_for_each_entry(q, &all_q_list, all_q_node) |
| blk_mq_freeze_queue_start(q); |
| list_for_each_entry(q, &all_q_list, all_q_node) { |
| blk_mq_freeze_queue_wait(q); |
| |
| /* |
| * timeout handler can't touch hw queue during the |
| * reinitialization |
| */ |
| del_timer_sync(&q->timeout); |
| } |
| |
| list_for_each_entry(q, &all_q_list, all_q_node) |
| blk_mq_queue_reinit(q, &online_new); |
| |
| list_for_each_entry(q, &all_q_list, all_q_node) |
| blk_mq_unfreeze_queue(q); |
| |
| mutex_unlock(&all_q_mutex); |
| return NOTIFY_OK; |
| } |
| |
| static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) |
| { |
| int i; |
| |
| for (i = 0; i < set->nr_hw_queues; i++) { |
| set->tags[i] = blk_mq_init_rq_map(set, i); |
| if (!set->tags[i]) |
| goto out_unwind; |
| } |
| |
| return 0; |
| |
| out_unwind: |
| while (--i >= 0) |
| blk_mq_free_rq_map(set, set->tags[i], i); |
| |
| return -ENOMEM; |
| } |
| |
| /* |
| * Allocate the request maps associated with this tag_set. Note that this |
| * may reduce the depth asked for, if memory is tight. set->queue_depth |
| * will be updated to reflect the allocated depth. |
| */ |
| static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) |
| { |
| unsigned int depth; |
| int err; |
| |
| depth = set->queue_depth; |
| do { |
| err = __blk_mq_alloc_rq_maps(set); |
| if (!err) |
| break; |
| |
| set->queue_depth >>= 1; |
| if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) { |
| err = -ENOMEM; |
| break; |
| } |
| } while (set->queue_depth); |
| |
| if (!set->queue_depth || err) { |
| pr_err("blk-mq: failed to allocate request map\n"); |
| return -ENOMEM; |
| } |
| |
| if (depth != set->queue_depth) |
| pr_info("blk-mq: reduced tag depth (%u -> %u)\n", |
| depth, set->queue_depth); |
| |
| return 0; |
| } |
| |
| struct cpumask *blk_mq_tags_cpumask(struct blk_mq_tags *tags) |
| { |
| return tags->cpumask; |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_tags_cpumask); |
| |
| /* |
| * Alloc a tag set to be associated with one or more request queues. |
| * May fail with EINVAL for various error conditions. May adjust the |
| * requested depth down, if if it too large. In that case, the set |
| * value will be stored in set->queue_depth. |
| */ |
| int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) |
| { |
| BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS); |
| |
| if (!set->nr_hw_queues) |
| return -EINVAL; |
| if (!set->queue_depth) |
| return -EINVAL; |
| if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) |
| return -EINVAL; |
| |
| if (!set->ops->queue_rq || !set->ops->map_queue) |
| return -EINVAL; |
| |
| if (set->queue_depth > BLK_MQ_MAX_DEPTH) { |
| pr_info("blk-mq: reduced tag depth to %u\n", |
| BLK_MQ_MAX_DEPTH); |
| set->queue_depth = BLK_MQ_MAX_DEPTH; |
| } |
| |
| /* |
| * If a crashdump is active, then we are potentially in a very |
| * memory constrained environment. Limit us to 1 queue and |
| * 64 tags to prevent using too much memory. |
| */ |
| if (is_kdump_kernel()) { |
| set->nr_hw_queues = 1; |
| set->queue_depth = min(64U, set->queue_depth); |
| } |
| |
| set->tags = kmalloc_node(set->nr_hw_queues * |
| sizeof(struct blk_mq_tags *), |
| GFP_KERNEL, set->numa_node); |
| if (!set->tags) |
| return -ENOMEM; |
| |
| if (blk_mq_alloc_rq_maps(set)) |
| goto enomem; |
| |
| mutex_init(&set->tag_list_lock); |
| INIT_LIST_HEAD(&set->tag_list); |
| |
| return 0; |
| enomem: |
| kfree(set->tags); |
| set->tags = NULL; |
| return -ENOMEM; |
| } |
| EXPORT_SYMBOL(blk_mq_alloc_tag_set); |
| |
| void blk_mq_free_tag_set(struct blk_mq_tag_set *set) |
| { |
| int i; |
| |
| for (i = 0; i < set->nr_hw_queues; i++) { |
| if (set->tags[i]) |
| blk_mq_free_rq_map(set, set->tags[i], i); |
| } |
| |
| kfree(set->tags); |
| set->tags = NULL; |
| } |
| EXPORT_SYMBOL(blk_mq_free_tag_set); |
| |
| int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) |
| { |
| struct blk_mq_tag_set *set = q->tag_set; |
| struct blk_mq_hw_ctx *hctx; |
| int i, ret; |
| |
| if (!set || nr > set->queue_depth) |
| return -EINVAL; |
| |
| ret = 0; |
| queue_for_each_hw_ctx(q, hctx, i) { |
| ret = blk_mq_tag_update_depth(hctx->tags, nr); |
| if (ret) |
| break; |
| } |
| |
| if (!ret) |
| q->nr_requests = nr; |
| |
| return ret; |
| } |
| |
| void blk_mq_disable_hotplug(void) |
| { |
| mutex_lock(&all_q_mutex); |
| } |
| |
| void blk_mq_enable_hotplug(void) |
| { |
| mutex_unlock(&all_q_mutex); |
| } |
| |
| static int __init blk_mq_init(void) |
| { |
| blk_mq_cpu_init(); |
| |
| hotcpu_notifier(blk_mq_queue_reinit_notify, 0); |
| |
| return 0; |
| } |
| subsys_initcall(blk_mq_init); |