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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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/blk-mq.h>
 #include <linux/delay.h>
 #include "blk.h"
 #include "blk-mq.h"
 #include "blk-mq-sched.h"
 #include "blk-mq-tag.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 (!users)
         return;
 
     sbitmap_queue_recalculate_wake_batch(&tags->bitmap_tags,
             users);
     sbitmap_queue_recalculate_wake_batch(&tags->breserved_tags,
             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)
 {
     unsigned int users;
 
     if (blk_mq_is_shared_tags(hctx->flags)) {
         struct request_queue *q = hctx->queue;
 
         if (test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags))
             return;
         set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags);
     } else {
         if (test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
             return;
         set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state);
     }
 
     users = atomic_inc_return(&hctx->tags->active_queues);
 
     blk_mq_update_wake_batch(hctx->tags, users);
 }
 
 /*
  * Wakeup all potentially sleeping on tags
  */
 void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
 {
     sbitmap_queue_wake_all(&tags->bitmap_tags);
     if (include_reserve)
         sbitmap_queue_wake_all(&tags->breserved_tags);
 }
 
 /*
  * 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)
 {
     struct blk_mq_tags *tags = hctx->tags;
     unsigned int users;
 
     if (blk_mq_is_shared_tags(hctx->flags)) {
         struct request_queue *q = hctx->queue;
 
         if (!test_and_clear_bit(QUEUE_FLAG_HCTX_ACTIVE,
                     &q->queue_flags))
             return;
     } else {
         if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
             return;
     }
 
     users = atomic_dec_return(&tags->active_queues);
 
     blk_mq_update_wake_batch(tags, users);
 
     blk_mq_tag_wakeup_all(tags, false);
 }
 
 static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
                 struct sbitmap_queue *bt)
 {
     if (!data->q->elevator && !(data->flags & BLK_MQ_REQ_RESERVED) &&
             !hctx_may_queue(data->hctx, bt))
         return BLK_MQ_NO_TAG;
 
     if (data->shallow_depth)
         return sbitmap_queue_get_shallow(bt, data->shallow_depth);
     else
         return __sbitmap_queue_get(bt);
 }
 
 unsigned long blk_mq_get_tags(struct blk_mq_alloc_data *data, int nr_tags,
                   unsigned int *offset)
 {
     struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
     struct sbitmap_queue *bt = &tags->bitmap_tags;
     unsigned long ret;
 
     if (data->shallow_depth ||data->flags & BLK_MQ_REQ_RESERVED ||
         data->hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
         return 0;
     ret = __sbitmap_queue_get_batch(bt, nr_tags, offset);
     *offset += tags->nr_reserved_tags;
     return ret;
 }
 
 unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
 {
     struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
     struct sbitmap_queue *bt;
     struct sbq_wait_state *ws;
     DEFINE_SBQ_WAIT(wait);
     unsigned int tag_offset;
     int tag;
 
     if (data->flags & BLK_MQ_REQ_RESERVED) {
         if (unlikely(!tags->nr_reserved_tags)) {
             WARN_ON_ONCE(1);
             return BLK_MQ_NO_TAG;
         }
         bt = &tags->breserved_tags;
         tag_offset = 0;
     } else {
         bt = &tags->bitmap_tags;
         tag_offset = tags->nr_reserved_tags;
     }
 
     tag = __blk_mq_get_tag(data, bt);
     if (tag != BLK_MQ_NO_TAG)
         goto found_tag;
 
     if (data->flags & BLK_MQ_REQ_NOWAIT)
         return BLK_MQ_NO_TAG;
 
     ws = bt_wait_ptr(bt, data->hctx);
     do {
         struct sbitmap_queue *bt_prev;
 
         /*
          * We're out of tags on this hardware queue, kick any
          * pending IO submits before going to sleep waiting for
          * some to complete.
          */
         blk_mq_run_hw_queue(data->hctx, false);
 
         /*
          * Retry tag allocation after running the hardware queue,
          * as running the queue may also have found completions.
          */
         tag = __blk_mq_get_tag(data, bt);
         if (tag != BLK_MQ_NO_TAG)
             break;
 
         sbitmap_prepare_to_wait(bt, ws, &wait, TASK_UNINTERRUPTIBLE);
 
         tag = __blk_mq_get_tag(data, bt);
         if (tag != BLK_MQ_NO_TAG)
             break;
 
         bt_prev = bt;
         io_schedule();
 
         sbitmap_finish_wait(bt, ws, &wait);
 
         data->ctx = blk_mq_get_ctx(data->q);
         data->hctx = blk_mq_map_queue(data->q, data->cmd_flags,
                         data->ctx);
         tags = blk_mq_tags_from_data(data);
         if (data->flags & BLK_MQ_REQ_RESERVED)
             bt = &tags->breserved_tags;
         else
             bt = &tags->bitmap_tags;
 
         /*
          * If destination hw queue is changed, fake wake up on
          * previous queue for compensating the wake up miss, so
          * other allocations on previous queue won't be starved.
          */
         if (bt != bt_prev)
             sbitmap_queue_wake_up(bt_prev);
 
         ws = bt_wait_ptr(bt, data->hctx);
     } while (1);
 
     sbitmap_finish_wait(bt, ws, &wait);
 
 found_tag:
     /*
      * Give up this allocation if the hctx is inactive.  The caller will
      * retry on an active hctx.
      */
     if (unlikely(test_bit(BLK_MQ_S_INACTIVE, &data->hctx->state))) {
         blk_mq_put_tag(tags, data->ctx, tag + tag_offset);
         return BLK_MQ_NO_TAG;
     }
     return tag + tag_offset;
 }
 
 void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
             unsigned int tag)
 {
     if (!blk_mq_tag_is_reserved(tags, tag)) {
         const int real_tag = tag - tags->nr_reserved_tags;
 
         BUG_ON(real_tag >= tags->nr_tags);
         sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
     } else {
         sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
     }
 }
 
 void blk_mq_put_tags(struct blk_mq_tags *tags, int *tag_array, int nr_tags)
 {
     sbitmap_queue_clear_batch(&tags->bitmap_tags, tags->nr_reserved_tags,
                     tag_array, nr_tags);
 }
 
 struct bt_iter_data {
     struct blk_mq_hw_ctx *hctx;
     struct request_queue *q;
     busy_tag_iter_fn *fn;
     void *data;
     bool reserved;
 };
 
 static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags,
         unsigned int bitnr)
 {
     struct request *rq;
     unsigned long flags;
 
     spin_lock_irqsave(&tags->lock, flags);
     rq = tags->rqs[bitnr];
     if (!rq || rq->tag != bitnr || !req_ref_inc_not_zero(rq))
         rq = NULL;
     spin_unlock_irqrestore(&tags->lock, flags);
     return rq;
 }
 
 static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
 {
     struct bt_iter_data *iter_data = data;
     struct blk_mq_hw_ctx *hctx = iter_data->hctx;
     struct request_queue *q = iter_data->q;
     struct blk_mq_tag_set *set = q->tag_set;
     struct blk_mq_tags *tags;
     struct request *rq;
     bool ret = true;
 
     if (blk_mq_is_shared_tags(set->flags))
         tags = set->shared_tags;
     else
         tags = hctx->tags;
 
     if (!iter_data->reserved)
         bitnr += tags->nr_reserved_tags;
     /*
      * We can hit rq == NULL here, because the tagging functions
      * test and set the bit before assigning ->rqs[].
      */
     rq = blk_mq_find_and_get_req(tags, bitnr);
     if (!rq)
         return true;
 
     if (rq->q == q && (!hctx || rq->mq_hctx == hctx))
         ret = iter_data->fn(rq, iter_data->data);
     blk_mq_put_rq_ref(rq);
     return ret;
 }
 
 /**
  * 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_iter_data iter_data = {
         .hctx = hctx,
         .fn = fn,
         .data = data,
         .reserved = reserved,
         .q = q,
     };
 
     sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
 }
 
 struct bt_tags_iter_data {
     struct blk_mq_tags *tags;
     busy_tag_iter_fn *fn;
     void *data;
     unsigned int flags;
 };
 
 #define BT_TAG_ITER_RESERVED        (1 << 0)
 #define BT_TAG_ITER_STARTED     (1 << 1)
 #define BT_TAG_ITER_STATIC_RQS      (1 << 2)
 
 static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
 {
     struct bt_tags_iter_data *iter_data = data;
     struct blk_mq_tags *tags = iter_data->tags;
     struct request *rq;
     bool ret = true;
     bool iter_static_rqs = !!(iter_data->flags & BT_TAG_ITER_STATIC_RQS);
 
     if (!(iter_data->flags & BT_TAG_ITER_RESERVED))
         bitnr += tags->nr_reserved_tags;
 
     /*
      * We can hit rq == NULL here, because the tagging functions
      * test and set the bit before assigning ->rqs[].
      */
     if (iter_static_rqs)
         rq = tags->static_rqs[bitnr];
     else
         rq = blk_mq_find_and_get_req(tags, bitnr);
     if (!rq)
         return true;
 
     if (!(iter_data->flags & BT_TAG_ITER_STARTED) ||
         blk_mq_request_started(rq))
         ret = iter_data->fn(rq, iter_data->data);
     if (!iter_static_rqs)
         blk_mq_put_rq_ref(rq);
     return ret;
 }
 
 /**
  * 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)
 {
     struct bt_tags_iter_data iter_data = {
         .tags = tags,
         .fn = fn,
         .data = data,
         .flags = flags,
     };
 
     if (tags->rqs)
         sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
 }
 
 static void __blk_mq_all_tag_iter(struct blk_mq_tags *tags,
         busy_tag_iter_fn *fn, void *priv, unsigned int flags)
 {
     WARN_ON_ONCE(flags & BT_TAG_ITER_RESERVED);
 
     if (tags->nr_reserved_tags)
         bt_tags_for_each(tags, &tags->breserved_tags, fn, priv,
                  flags | BT_TAG_ITER_RESERVED);
     bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, 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_all_tag_iter(tags, fn, priv, BT_TAG_ITER_STATIC_RQS);
 }
 
 /**
  * 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)
 {
     unsigned int flags = tagset->flags;
     int i, nr_tags;
 
     nr_tags = blk_mq_is_shared_tags(flags) ? 1 : tagset->nr_hw_queues;
 
     for (i = 0; i < nr_tags; i++) {
         if (tagset->tags && tagset->tags[i])
             __blk_mq_all_tag_iter(tagset->tags[i], fn, priv,
                           BT_TAG_ITER_STARTED);
     }
 }
 EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
 
 static bool blk_mq_tagset_count_completed_rqs(struct request *rq, void *data)
 {
     unsigned *count = data;
 
     if (blk_mq_request_completed(rq))
         (*count)++;
     return true;
 }
 
 /**
  * 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)
 {
     while (true) {
         unsigned count = 0;
 
         blk_mq_tagset_busy_iter(tagset,
                 blk_mq_tagset_count_completed_rqs, &count);
         if (!count)
             break;
         msleep(5);
     }
 }
 EXPORT_SYMBOL(blk_mq_tagset_wait_completed_request);
 
 /**
  * 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)
 {
     /*
      * __blk_mq_update_nr_hw_queues() updates nr_hw_queues and hctx_table
      * while the queue is frozen. So we can use q_usage_counter to avoid
      * racing with it.
      */
     if (!percpu_ref_tryget(&q->q_usage_counter))
         return;
 
     if (blk_mq_is_shared_tags(q->tag_set->flags)) {
         struct blk_mq_tags *tags = q->tag_set->shared_tags;
         struct sbitmap_queue *bresv = &tags->breserved_tags;
         struct sbitmap_queue *btags = &tags->bitmap_tags;
 
         if (tags->nr_reserved_tags)
             bt_for_each(NULL, q, bresv, fn, priv, true);
         bt_for_each(NULL, q, btags, fn, priv, false);
     } else {
         struct blk_mq_hw_ctx *hctx;
         unsigned long i;
 
         queue_for_each_hw_ctx(q, hctx, i) {
             struct blk_mq_tags *tags = hctx->tags;
             struct sbitmap_queue *bresv = &tags->breserved_tags;
             struct sbitmap_queue *btags = &tags->bitmap_tags;
 
             /*
              * If no software queues are currently mapped to this
              * hardware queue, there's nothing to check
              */
             if (!blk_mq_hw_queue_mapped(hctx))
                 continue;
 
             if (tags->nr_reserved_tags)
                 bt_for_each(hctx, q, bresv, fn, priv, true);
             bt_for_each(hctx, q, btags, fn, priv, false);
         }
     }
     blk_queue_exit(q);
 }
 
 static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
             bool round_robin, int node)
 {
     return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
                        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)
 {
     unsigned int depth = queue_depth - reserved;
     bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
 
     if (bt_alloc(bitmap_tags, depth, round_robin, node))
         return -ENOMEM;
     if (bt_alloc(breserved_tags, reserved, round_robin, node))
         goto free_bitmap_tags;
 
     return 0;
 
 free_bitmap_tags:
     sbitmap_queue_free(bitmap_tags);
     return -ENOMEM;
 }
 
 struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
                      unsigned int reserved_tags,
                      int node, int alloc_policy)
 {
     struct blk_mq_tags *tags;
 
     if (total_tags > BLK_MQ_TAG_MAX) {
         pr_err("blk-mq: tag depth too large\n");
         return NULL;
     }
 
     tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
     if (!tags)
         return NULL;
 
     tags->nr_tags = total_tags;
     tags->nr_reserved_tags = reserved_tags;
     spin_lock_init(&tags->lock);
 
     if (blk_mq_init_bitmaps(&tags->bitmap_tags, &tags->breserved_tags,
                 total_tags, reserved_tags, node,
                 alloc_policy) < 0) {
         kfree(tags);
         return NULL;
     }
     return tags;
 }
 
 void blk_mq_free_tags(struct blk_mq_tags *tags)
 {
     sbitmap_queue_free(&tags->bitmap_tags);
     sbitmap_queue_free(&tags->breserved_tags);
     kfree(tags);
 }
 
 int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
                 struct blk_mq_tags **tagsptr, unsigned int tdepth,
                 bool can_grow)
 {
     struct blk_mq_tags *tags = *tagsptr;
 
     if (tdepth <= tags->nr_reserved_tags)
         return -EINVAL;
 
     /*
      * If we are allowed to grow beyond the original size, allocate
      * a new set of tags before freeing the old one.
      */
     if (tdepth > tags->nr_tags) {
         struct blk_mq_tag_set *set = hctx->queue->tag_set;
         struct blk_mq_tags *new;
 
         if (!can_grow)
             return -EINVAL;
 
         /*
          * We need some sort of upper limit, set it high enough that
          * no valid use cases should require more.
          */
         if (tdepth > MAX_SCHED_RQ)
             return -EINVAL;
 
         /*
          * Only the sbitmap needs resizing since we allocated the max
          * initially.
          */
         if (blk_mq_is_shared_tags(set->flags))
             return 0;
 
         new = blk_mq_alloc_map_and_rqs(set, hctx->queue_num, tdepth);
         if (!new)
             return -ENOMEM;
 
         blk_mq_free_map_and_rqs(set, *tagsptr, hctx->queue_num);
         *tagsptr = new;
     } else {
         /*
          * Don't need (or can't) update reserved tags here, they
          * remain static and should never need resizing.
          */
         sbitmap_queue_resize(&tags->bitmap_tags,
                 tdepth - tags->nr_reserved_tags);
     }
 
     return 0;
 }
 
 void blk_mq_tag_resize_shared_tags(struct blk_mq_tag_set *set, unsigned int size)
 {
     struct blk_mq_tags *tags = set->shared_tags;
 
     sbitmap_queue_resize(&tags->bitmap_tags, size - set->reserved_tags);
 }
 
 void blk_mq_tag_update_sched_shared_tags(struct request_queue *q)
 {
     sbitmap_queue_resize(&q->sched_shared_tags->bitmap_tags,
                  q->nr_requests - q->tag_set->reserved_tags);
 }
 
 /**
  * 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)
 {
     return (rq->mq_hctx->queue_num << BLK_MQ_UNIQUE_TAG_BITS) |
         (rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
 }
 EXPORT_SYMBOL(blk_mq_unique_tag);

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