diff options
| -rw-r--r-- | Documentation/block/biodoc.txt | 88 | ||||
| -rw-r--r-- | block/Makefile | 2 | ||||
| -rw-r--r-- | block/blk-core.c | 6 | ||||
| -rw-r--r-- | block/blk-mq-debugfs.c | 2 | ||||
| -rw-r--r-- | block/blk-mq-tag.c | 6 | ||||
| -rw-r--r-- | block/blk-sysfs.c | 3 | ||||
| -rw-r--r-- | block/blk-tag.c | 378 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 35 |
8 files changed, 3 insertions, 517 deletions
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index 207eca58efaa..ac18b488cb5e 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt @@ -65,7 +65,6 @@ Description of Contents: 3.2.3 I/O completion 3.2.4 Implications for drivers that do not interpret bios (don't handle multiple segments) - 3.2.5 Request command tagging 3.3 I/O submission 4. The I/O scheduler 5. Scalability related changes @@ -708,93 +707,6 @@ is crossed on completion of a transfer. (The end*request* functions should be used if only if the request has come down from block/bio path, not for direct access requests which only specify rq->buffer without a valid rq->bio) -3.2.5 Generic request command tagging - -3.2.5.1 Tag helpers - -Block now offers some simple generic functionality to help support command -queueing (typically known as tagged command queueing), ie manage more than -one outstanding command on a queue at any given time. - - blk_queue_init_tags(struct request_queue *q, int depth) - - Initialize internal command tagging structures for a maximum - depth of 'depth'. - - blk_queue_free_tags((struct request_queue *q) - - Teardown tag info associated with the queue. This will be done - automatically by block if blk_queue_cleanup() is called on a queue - that is using tagging. - -The above are initialization and exit management, the main helpers during -normal operations are: - - blk_queue_start_tag(struct request_queue *q, struct request *rq) - - Start tagged operation for this request. A free tag number between - 0 and 'depth' is assigned to the request (rq->tag holds this number), - and 'rq' is added to the internal tag management. If the maximum depth - for this queue is already achieved (or if the tag wasn't started for - some other reason), 1 is returned. Otherwise 0 is returned. - - blk_queue_end_tag(struct request_queue *q, struct request *rq) - - End tagged operation on this request. 'rq' is removed from the internal - book keeping structures. - -To minimize struct request and queue overhead, the tag helpers utilize some -of the same request members that are used for normal request queue management. -This means that a request cannot both be an active tag and be on the queue -list at the same time. blk_queue_start_tag() will remove the request, but -the driver must remember to call blk_queue_end_tag() before signalling -completion of the request to the block layer. This means ending tag -operations before calling end_that_request_last()! For an example of a user -of these helpers, see the IDE tagged command queueing support. - -3.2.5.2 Tag info - -Some block functions exist to query current tag status or to go from a -tag number to the associated request. These are, in no particular order: - - blk_queue_tagged(q) - - Returns 1 if the queue 'q' is using tagging, 0 if not. - - blk_queue_tag_request(q, tag) - - Returns a pointer to the request associated with tag 'tag'. - - blk_queue_tag_depth(q) - - Return current queue depth. - - blk_queue_tag_queue(q) - - Returns 1 if the queue can accept a new queued command, 0 if we are - at the maximum depth already. - - blk_queue_rq_tagged(rq) - - Returns 1 if the request 'rq' is tagged. - -3.2.5.2 Internal structure - -Internally, block manages tags in the blk_queue_tag structure: - - struct blk_queue_tag { - struct request **tag_index; /* array or pointers to rq */ - unsigned long *tag_map; /* bitmap of free tags */ - struct list_head busy_list; /* fifo list of busy tags */ - int busy; /* queue depth */ - int max_depth; /* max queue depth */ - }; - -Most of the above is simple and straight forward, however busy_list may need -a bit of explaining. Normally we don't care too much about request ordering, -but in the event of any barrier requests in the tag queue we need to ensure -that requests are restarted in the order they were queue. - 3.3 I/O Submission The routine submit_bio() is used to submit a single io. Higher level i/o diff --git a/block/Makefile b/block/Makefile index 27eac600474f..213674c8faaa 100644 --- a/block/Makefile +++ b/block/Makefile @@ -3,7 +3,7 @@ # Makefile for the kernel block layer # -obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-tag.o blk-sysfs.o \ +obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-sysfs.o \ blk-flush.o blk-settings.o blk-ioc.o blk-map.o \ blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \ blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \ diff --git a/block/blk-core.c b/block/blk-core.c index 03ef8f0e7dc5..daaed4dfa719 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1658,9 +1658,6 @@ void blk_requeue_request(struct request_queue *q, struct request *rq) trace_block_rq_requeue(q, rq); rq_qos_requeue(q, rq); - if (rq->rq_flags & RQF_QUEUED) - blk_queue_end_tag(q, rq); - BUG_ON(blk_queued_rq(rq)); elv_requeue_request(q, rq); @@ -3174,9 +3171,6 @@ void blk_finish_request(struct request *req, blk_status_t error) if (req->rq_flags & RQF_STATS) blk_stat_add(req, now); - if (req->rq_flags & RQF_QUEUED) - blk_queue_end_tag(q, req); - BUG_ON(blk_queued_rq(req)); if (unlikely(laptop_mode) && !blk_rq_is_passthrough(req)) diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index 10b284a1f18d..9ed43a7c70b5 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -112,7 +112,6 @@ static int queue_pm_only_show(void *data, struct seq_file *m) #define QUEUE_FLAG_NAME(name) [QUEUE_FLAG_##name] = #name static const char *const blk_queue_flag_name[] = { - QUEUE_FLAG_NAME(QUEUED), QUEUE_FLAG_NAME(STOPPED), QUEUE_FLAG_NAME(DYING), QUEUE_FLAG_NAME(BYPASS), @@ -318,7 +317,6 @@ static const char *const cmd_flag_name[] = { static const char *const rqf_name[] = { RQF_NAME(SORTED), RQF_NAME(STARTED), - RQF_NAME(QUEUED), RQF_NAME(SOFTBARRIER), RQF_NAME(FLUSH_SEQ), RQF_NAME(MIXED_MERGE), diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index cfda95b85d34..4254e74c1446 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -530,10 +530,8 @@ u32 blk_mq_unique_tag(struct request *rq) struct blk_mq_hw_ctx *hctx; int hwq = 0; - if (q->mq_ops) { - hctx = blk_mq_map_queue(q, rq->mq_ctx->cpu); - hwq = hctx->queue_num; - } + hctx = blk_mq_map_queue(q, rq->mq_ctx->cpu); + hwq = hctx->queue_num; return (hwq << BLK_MQ_UNIQUE_TAG_BITS) | (rq->tag & BLK_MQ_UNIQUE_TAG_MASK); diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 844a454a7b3a..1b82ccfde3fe 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -849,9 +849,6 @@ static void __blk_release_queue(struct work_struct *work) blk_exit_rl(q, &q->root_rl); - if (q->queue_tags) - __blk_queue_free_tags(q); - blk_queue_free_zone_bitmaps(q); if (!q->mq_ops) { diff --git a/block/blk-tag.c b/block/blk-tag.c deleted file mode 100644 index fbc153aef166..000000000000 --- a/block/blk-tag.c +++ /dev/null @@ -1,378 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * Functions related to tagged command queuing - */ -#include <linux/kernel.h> -#include <linux/module.h> -#include <linux/bio.h> -#include <linux/blkdev.h> -#include <linux/slab.h> - -#include "blk.h" - -/** - * blk_queue_find_tag - find a request by its tag and queue - * @q: The request queue for the device - * @tag: The tag of the request - * - * Notes: - * Should be used when a device returns a tag and you want to match - * it with a request. - * - * no locks need be held. - **/ -struct request *blk_queue_find_tag(struct request_queue *q, int tag) -{ - return blk_map_queue_find_tag(q->queue_tags, tag); -} -EXPORT_SYMBOL(blk_queue_find_tag); - -/** - * blk_free_tags - release a given set of tag maintenance info - * @bqt: the tag map to free - * - * Drop the reference count on @bqt and frees it when the last reference - * is dropped. - */ -void blk_free_tags(struct blk_queue_tag *bqt) -{ - if (atomic_dec_and_test(&bqt->refcnt)) { - BUG_ON(find_first_bit(bqt->tag_map, bqt->max_depth) < - bqt->max_depth); - - kfree(bqt->tag_index); - bqt->tag_index = NULL; - - kfree(bqt->tag_map); - bqt->tag_map = NULL; - - kfree(bqt); - } -} -EXPORT_SYMBOL(blk_free_tags); - -/** - * __blk_queue_free_tags - release tag maintenance info - * @q: the request queue for the device - * - * Notes: - * blk_cleanup_queue() will take care of calling this function, if tagging - * has been used. So there's no need to call this directly. - **/ -void __blk_queue_free_tags(struct request_queue *q) -{ - struct blk_queue_tag *bqt = q->queue_tags; - - if (!bqt) - return; - - blk_free_tags(bqt); - - q->queue_tags = NULL; - queue_flag_clear_unlocked(QUEUE_FLAG_QUEUED, q); -} - -/** - * blk_queue_free_tags - release tag maintenance info - * @q: the request queue for the device - * - * Notes: - * This is used to disable tagged queuing to a device, yet leave - * queue in function. - **/ -void blk_queue_free_tags(struct request_queue *q) -{ - queue_flag_clear_unlocked(QUEUE_FLAG_QUEUED, q); -} -EXPORT_SYMBOL(blk_queue_free_tags); - -static int -init_tag_map(struct request_queue *q, struct blk_queue_tag *tags, int depth) -{ - struct request **tag_index; - unsigned long *tag_map; - int nr_ulongs; - - if (q && depth > q->nr_requests * 2) { - depth = q->nr_requests * 2; - printk(KERN_ERR "%s: adjusted depth to %d\n", - __func__, depth); - } - - tag_index = kcalloc(depth, sizeof(struct request *), GFP_ATOMIC); - if (!tag_index) - goto fail; - - nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG; - tag_map = kcalloc(nr_ulongs, sizeof(unsigned long), GFP_ATOMIC); - if (!tag_map) - goto fail; - - tags->real_max_depth = depth; - tags->max_depth = depth; - tags->tag_index = tag_index; - tags->tag_map = tag_map; - - return 0; -fail: - kfree(tag_index); - return -ENOMEM; -} - -static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q, - int depth, int alloc_policy) -{ - struct blk_queue_tag *tags; - - tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC); - if (!tags) - goto fail; - - if (init_tag_map(q, tags, depth)) - goto fail; - - atomic_set(&tags->refcnt, 1); - tags->alloc_policy = alloc_policy; - tags->next_tag = 0; - return tags; -fail: - kfree(tags); - return NULL; -} - -/** - * blk_init_tags - initialize the tag info for an external tag map - * @depth: the maximum queue depth supported - * @alloc_policy: tag allocation policy - **/ -struct blk_queue_tag *blk_init_tags(int depth, int alloc_policy) -{ - return __blk_queue_init_tags(NULL, depth, alloc_policy); -} -EXPORT_SYMBOL(blk_init_tags); - -/** - * blk_queue_init_tags - initialize the queue tag info - * @q: the request queue for the device - * @depth: the maximum queue depth supported - * @tags: the tag to use - * @alloc_policy: tag allocation policy - * - * Queue lock must be held here if the function is called to resize an - * existing map. - **/ -int blk_queue_init_tags(struct request_queue *q, int depth, - struct blk_queue_tag *tags, int alloc_policy) -{ - int rc; - - BUG_ON(tags && q->queue_tags && tags != q->queue_tags); - - if (!tags && !q->queue_tags) { - tags = __blk_queue_init_tags(q, depth, alloc_policy); - - if (!tags) - return -ENOMEM; - - } else if (q->queue_tags) { - rc = blk_queue_resize_tags(q, depth); - if (rc) - return rc; - queue_flag_set(QUEUE_FLAG_QUEUED, q); - return 0; - } else - atomic_inc(&tags->refcnt); - - /* - * assign it, all done - */ - q->queue_tags = tags; - queue_flag_set_unlocked(QUEUE_FLAG_QUEUED, q); - return 0; -} -EXPORT_SYMBOL(blk_queue_init_tags); - -/** - * blk_queue_resize_tags - change the queueing depth - * @q: the request queue for the device - * @new_depth: the new max command queueing depth - * - * Notes: - * Must be called with the queue lock held. - **/ -int blk_queue_resize_tags(struct request_queue *q, int new_depth) -{ - struct blk_queue_tag *bqt = q->queue_tags; - struct request **tag_index; - unsigned long *tag_map; - int max_depth, nr_ulongs; - - if (!bqt) - return -ENXIO; - - /* - * if we already have large enough real_max_depth. just - * adjust max_depth. *NOTE* as requests with tag value - * between new_depth and real_max_depth can be in-flight, tag - * map can not be shrunk blindly here. - */ - if (new_depth <= bqt->real_max_depth) { - bqt->max_depth = new_depth; - return 0; - } - - /* - * Currently cannot replace a shared tag map with a new - * one, so error out if this is the case - */ - if (atomic_read(&bqt->refcnt) != 1) - return -EBUSY; - - /* - * save the old state info, so we can copy it back - */ - tag_index = bqt->tag_index; - tag_map = bqt->tag_map; - max_depth = bqt->real_max_depth; - - if (init_tag_map(q, bqt, new_depth)) - return -ENOMEM; - - memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *)); - nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG; - memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long)); - - kfree(tag_index); - kfree(tag_map); - return 0; -} -EXPORT_SYMBOL(blk_queue_resize_tags); - -/** - * blk_queue_end_tag - end tag operations for a request - * @q: the request queue for the device - * @rq: the request that has completed - * - * Description: - * Typically called when end_that_request_first() returns %0, meaning - * all transfers have been done for a request. It's important to call - * this function before end_that_request_last(), as that will put the - * request back on the free list thus corrupting the internal tag list. - **/ -void blk_queue_end_tag(struct request_queue *q, struct request *rq) -{ - struct blk_queue_tag *bqt = q->queue_tags; - unsigned tag = rq->tag; /* negative tags invalid */ - - lockdep_assert_held(q->queue_lock); - - BUG_ON(tag >= bqt->real_max_depth); - - list_del_init(&rq->queuelist); - rq->rq_flags &= ~RQF_QUEUED; - rq->tag = -1; - rq->internal_tag = -1; - - if (unlikely(bqt->tag_index[tag] == NULL)) - printk(KERN_ERR "%s: tag %d is missing\n", - __func__, tag); - - bqt->tag_index[tag] = NULL; - - if (unlikely(!test_bit(tag, bqt->tag_map))) { - printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n", - __func__, tag); - return; - } - /* - * The tag_map bit acts as a lock for tag_index[bit], so we need - * unlock memory barrier semantics. - */ - clear_bit_unlock(tag, bqt->tag_map); -} - -/** - * blk_queue_start_tag - find a free tag and assign it - * @q: the request queue for the device - * @rq: the block request that needs tagging - * - * Description: - * This can either be used as a stand-alone helper, or possibly be - * assigned as the queue &prep_rq_fn (in which case &struct request - * automagically gets a tag assigned). Note that this function - * assumes that any type of request can be queued! if this is not - * true for your device, you must check the request type before - * calling this function. The request will also be removed from - * the request queue, so it's the drivers responsibility to readd - * it if it should need to be restarted for some reason. - **/ -int blk_queue_start_tag(struct request_queue *q, struct request *rq) -{ - struct blk_queue_tag *bqt = q->queue_tags; - unsigned max_depth; - int tag; - - lockdep_assert_held(q->queue_lock); - - if (unlikely((rq->rq_flags & RQF_QUEUED))) { - printk(KERN_ERR - "%s: request %p for device [%s] already tagged %d", - __func__, rq, - rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag); - BUG(); - } - - /* - * Protect against shared tag maps, as we may not have exclusive - * access to the tag map. - * - * We reserve a few tags just for sync IO, since we don't want - * to starve sync IO on behalf of flooding async IO. - */ - max_depth = bqt->max_depth; - if (!rq_is_sync(rq) && max_depth > 1) { - switch (max_depth) { - case 2: - max_depth = 1; - break; - case 3: - max_depth = 2; - break; - default: - max_depth -= 2; - } - if (q->in_flight[BLK_RW_ASYNC] > max_depth) - return 1; - } - - do { - if (bqt->alloc_policy == BLK_TAG_ALLOC_FIFO) { - tag = find_first_zero_bit(bqt->tag_map, max_depth); - if (tag >= max_depth) - return 1; - } else { - int start = bqt->next_tag; - int size = min_t(int, bqt->max_depth, max_depth + start); - tag = find_next_zero_bit(bqt->tag_map, size, start); - if (tag >= size && start + size > bqt->max_depth) { - size = start + size - bqt->max_depth; - tag = find_first_zero_bit(bqt->tag_map, size); - } - if (tag >= size) - return 1; - } - - } while (test_and_set_bit_lock(tag, bqt->tag_map)); - /* - * We need lock ordering semantics given by test_and_set_bit_lock. - * See blk_queue_end_tag for details. - */ - - bqt->next_tag = (tag + 1) % bqt->max_depth; - rq->rq_flags |= RQF_QUEUED; - rq->tag = tag; - bqt->tag_index[tag] = rq; - blk_start_request(rq); - return 0; -} -EXPORT_SYMBOL(blk_queue_start_tag); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 6baea6563364..8afe3331777e 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -85,8 +85,6 @@ typedef __u32 __bitwise req_flags_t; #define RQF_SORTED ((__force req_flags_t)(1 << 0)) /* drive already may have started this one */ #define RQF_STARTED ((__force req_flags_t)(1 << 1)) -/* uses tagged queueing */ -#define RQF_QUEUED ((__force req_flags_t)(1 << 2)) /* may not be passed by ioscheduler */ #define RQF_SOFTBARRIER ((__force req_flags_t)(1 << 3)) /* request for flush sequence */ @@ -336,15 +334,6 @@ enum blk_queue_state { Queue_up, }; -struct blk_queue_tag { - struct request **tag_index; /* map of busy tags */ - unsigned long *tag_map; /* bit map of free/busy tags */ - int max_depth; /* what we will send to device */ - int real_max_depth; /* what the array can hold */ - atomic_t refcnt; /* map can be shared */ - int alloc_policy; /* tag allocation policy */ - int next_tag; /* next tag */ -}; #define BLK_TAG_ALLOC_FIFO 0 /* allocate starting from 0 */ #define BLK_TAG_ALLOC_RR 1 /* allocate starting from last allocated tag */ @@ -568,8 +557,6 @@ struct request_queue { unsigned int dma_pad_mask; unsigned int dma_alignment; - struct blk_queue_tag *queue_tags; - unsigned int nr_sorted; unsigned int in_flight[2]; @@ -680,7 +667,6 @@ struct request_queue { u64 write_hints[BLK_MAX_WRITE_HINTS]; }; -#define QUEUE_FLAG_QUEUED 0 /* uses generic tag queueing */ #define QUEUE_FLAG_STOPPED 1 /* queue is stopped */ #define QUEUE_FLAG_DYING 2 /* queue being torn down */ #define QUEUE_FLAG_BYPASS 3 /* act as dumb FIFO queue */ @@ -724,7 +710,6 @@ void blk_queue_flag_clear(unsigned int flag, struct request_queue *q); bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q); bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q); -#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags) #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags) #define blk_queue_dying(q) test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags) #define blk_queue_dead(q) test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags) @@ -1359,26 +1344,6 @@ static inline bool blk_needs_flush_plug(struct task_struct *tsk) !list_empty(&plug->cb_list)); } -/* - * tag stuff - */ -extern int blk_queue_start_tag(struct request_queue *, struct request *); -extern struct request *blk_queue_find_tag(struct request_queue *, int); -extern void blk_queue_end_tag(struct request_queue *, struct request *); -extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int); -extern void blk_queue_free_tags(struct request_queue *); -extern int blk_queue_resize_tags(struct request_queue *, int); -extern struct blk_queue_tag *blk_init_tags(int, int); -extern void blk_free_tags(struct blk_queue_tag *); - -static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt, - int tag) -{ - if (unlikely(bqt == NULL || tag >= bqt->real_max_depth)) - return NULL; - return bqt->tag_index[tag]; -} - extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *); extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, struct page *page); |