// SPDX-License-Identifier: GPL-2.0 /* * Tag allocation using scalable bitmaps. Uses active queue tracking to support * fairer distribution of tags between multiple submitters when a shared tag map * is used. * * Copyright (C) 2013-2014 Jens Axboe */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/delay.h> #include "blk.h" #include "blk-mq.h" #include "blk-mq-sched.h" /* * Recalculate wakeup batch when tag is shared by hctx. */ static void blk_mq_update_wake_batch(struct blk_mq_tags *tags, unsigned int users) { … } /* * If a previously inactive queue goes active, bump the active user count. * We need to do this before try to allocate driver tag, then even if fail * to get tag when first time, the other shared-tag users could reserve * budget for it. */ void __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx) { … } /* * Wakeup all potentially sleeping on tags */ void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve) { … } /* * If a previously busy queue goes inactive, potential waiters could now * be allowed to queue. Wake them up and check. */ void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx) { … } static int __blk_mq_get_tag(struct blk_mq_alloc_data *data, struct sbitmap_queue *bt) { … } unsigned long blk_mq_get_tags(struct blk_mq_alloc_data *data, int nr_tags, unsigned int *offset) { … } unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) { … } void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx, unsigned int tag) { … } void blk_mq_put_tags(struct blk_mq_tags *tags, int *tag_array, int nr_tags) { … } struct bt_iter_data { … }; static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags, unsigned int bitnr) { … } static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) { … } /** * bt_for_each - iterate over the requests associated with a hardware queue * @hctx: Hardware queue to examine. * @q: Request queue to examine. * @bt: sbitmap to examine. This is either the breserved_tags member * or the bitmap_tags member of struct blk_mq_tags. * @fn: Pointer to the function that will be called for each request * associated with @hctx that has been assigned a driver tag. * @fn will be called as follows: @fn(@hctx, rq, @data, @reserved) * where rq is a pointer to a request. Return true to continue * iterating tags, false to stop. * @data: Will be passed as third argument to @fn. * @reserved: Indicates whether @bt is the breserved_tags member or the * bitmap_tags member of struct blk_mq_tags. */ static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct request_queue *q, struct sbitmap_queue *bt, busy_tag_iter_fn *fn, void *data, bool reserved) { … } struct bt_tags_iter_data { … }; #define BT_TAG_ITER_RESERVED … #define BT_TAG_ITER_STARTED … #define BT_TAG_ITER_STATIC_RQS … static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) { … } /** * bt_tags_for_each - iterate over the requests in a tag map * @tags: Tag map to iterate over. * @bt: sbitmap to examine. This is either the breserved_tags member * or the bitmap_tags member of struct blk_mq_tags. * @fn: Pointer to the function that will be called for each started * request. @fn will be called as follows: @fn(rq, @data, * @reserved) where rq is a pointer to a request. Return true * to continue iterating tags, false to stop. * @data: Will be passed as second argument to @fn. * @flags: BT_TAG_ITER_* */ static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt, busy_tag_iter_fn *fn, void *data, unsigned int flags) { … } static void __blk_mq_all_tag_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn, void *priv, unsigned int flags) { … } /** * blk_mq_all_tag_iter - iterate over all requests in a tag map * @tags: Tag map to iterate over. * @fn: Pointer to the function that will be called for each * request. @fn will be called as follows: @fn(rq, @priv, * reserved) where rq is a pointer to a request. 'reserved' * indicates whether or not @rq is a reserved request. Return * true to continue iterating tags, false to stop. * @priv: Will be passed as second argument to @fn. * * Caller has to pass the tag map from which requests are allocated. */ void blk_mq_all_tag_iter(struct blk_mq_tags *tags, busy_tag_iter_fn *fn, void *priv) { … } /** * blk_mq_tagset_busy_iter - iterate over all started requests in a tag set * @tagset: Tag set to iterate over. * @fn: Pointer to the function that will be called for each started * request. @fn will be called as follows: @fn(rq, @priv, * reserved) where rq is a pointer to a request. 'reserved' * indicates whether or not @rq is a reserved request. Return * true to continue iterating tags, false to stop. * @priv: Will be passed as second argument to @fn. * * We grab one request reference before calling @fn and release it after * @fn returns. */ void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset, busy_tag_iter_fn *fn, void *priv) { … } EXPORT_SYMBOL(…); static bool blk_mq_tagset_count_completed_rqs(struct request *rq, void *data) { … } /** * blk_mq_tagset_wait_completed_request - Wait until all scheduled request * completions have finished. * @tagset: Tag set to drain completed request * * Note: This function has to be run after all IO queues are shutdown */ void blk_mq_tagset_wait_completed_request(struct blk_mq_tag_set *tagset) { … } EXPORT_SYMBOL(…); /** * blk_mq_queue_tag_busy_iter - iterate over all requests with a driver tag * @q: Request queue to examine. * @fn: Pointer to the function that will be called for each request * on @q. @fn will be called as follows: @fn(hctx, rq, @priv, * reserved) where rq is a pointer to a request and hctx points * to the hardware queue associated with the request. 'reserved' * indicates whether or not @rq is a reserved request. * @priv: Will be passed as third argument to @fn. * * Note: if @q->tag_set is shared with other request queues then @fn will be * called for all requests on all queues that share that tag set and not only * for requests associated with @q. */ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_tag_iter_fn *fn, void *priv) { … } static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth, bool round_robin, int node) { … } int blk_mq_init_bitmaps(struct sbitmap_queue *bitmap_tags, struct sbitmap_queue *breserved_tags, unsigned int queue_depth, unsigned int reserved, int node, int alloc_policy) { … } struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, unsigned int reserved_tags, int node, int alloc_policy) { … } void blk_mq_free_tags(struct blk_mq_tags *tags) { … } int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags **tagsptr, unsigned int tdepth, bool can_grow) { … } void blk_mq_tag_resize_shared_tags(struct blk_mq_tag_set *set, unsigned int size) { … } void blk_mq_tag_update_sched_shared_tags(struct request_queue *q) { … } /** * blk_mq_unique_tag() - return a tag that is unique queue-wide * @rq: request for which to compute a unique tag * * The tag field in struct request is unique per hardware queue but not over * all hardware queues. Hence this function that returns a tag with the * hardware context index in the upper bits and the per hardware queue tag in * the lower bits. * * Note: When called for a request that is queued on a non-multiqueue request * queue, the hardware context index is set to zero. */ u32 blk_mq_unique_tag(struct request *rq) { … } EXPORT_SYMBOL(…);
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