linux/block/blk-mq.h
Ming Lei 4e5cc99e1e blk-mq: manage hctx map via xarray
First code becomes more clean by switching to xarray from plain array.

Second use-after-free on q->queue_hw_ctx can be fixed because
queue_for_each_hw_ctx() may be run when updating nr_hw_queues is
in-progress. With this patch, q->hctx_table is defined as xarray, and
this structure will share same lifetime with request queue, so
queue_for_each_hw_ctx() can use q->hctx_table to lookup hctx reliably.

Reported-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220308073219.91173-7-ming.lei@redhat.com
[axboe: fix blk_mq_hw_ctx forward declaration]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-03-08 19:39:38 -07:00

398 lines
11 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef INT_BLK_MQ_H
#define INT_BLK_MQ_H
#include "blk-stat.h"
#include "blk-mq-tag.h"
struct blk_mq_tag_set;
struct blk_mq_ctxs {
struct kobject kobj;
struct blk_mq_ctx __percpu *queue_ctx;
};
/**
* struct blk_mq_ctx - State for a software queue facing the submitting CPUs
*/
struct blk_mq_ctx {
struct {
spinlock_t lock;
struct list_head rq_lists[HCTX_MAX_TYPES];
} ____cacheline_aligned_in_smp;
unsigned int cpu;
unsigned short index_hw[HCTX_MAX_TYPES];
struct blk_mq_hw_ctx *hctxs[HCTX_MAX_TYPES];
struct request_queue *queue;
struct blk_mq_ctxs *ctxs;
struct kobject kobj;
} ____cacheline_aligned_in_smp;
void blk_mq_submit_bio(struct bio *bio);
int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, struct io_comp_batch *iob,
unsigned int flags);
void blk_mq_exit_queue(struct request_queue *q);
int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr);
void blk_mq_wake_waiters(struct request_queue *q);
bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *,
unsigned int);
void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
bool kick_requeue_list);
void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list);
struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *start);
void blk_mq_put_rq_ref(struct request *rq);
/*
* Internal helpers for allocating/freeing the request map
*/
void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
unsigned int hctx_idx);
void blk_mq_free_rq_map(struct blk_mq_tags *tags);
struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
unsigned int hctx_idx, unsigned int depth);
void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
struct blk_mq_tags *tags,
unsigned int hctx_idx);
/*
* Internal helpers for request insertion into sw queues
*/
void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
bool at_head);
void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
bool run_queue);
void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
struct list_head *list);
void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
struct list_head *list);
/*
* CPU -> queue mappings
*/
extern int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int);
/*
* blk_mq_map_queue_type() - map (hctx_type,cpu) to hardware queue
* @q: request queue
* @type: the hctx type index
* @cpu: CPU
*/
static inline struct blk_mq_hw_ctx *blk_mq_map_queue_type(struct request_queue *q,
enum hctx_type type,
unsigned int cpu)
{
return xa_load(&q->hctx_table, q->tag_set->map[type].mq_map[cpu]);
}
static inline enum hctx_type blk_mq_get_hctx_type(unsigned int flags)
{
enum hctx_type type = HCTX_TYPE_DEFAULT;
/*
* The caller ensure that if REQ_POLLED, poll must be enabled.
*/
if (flags & REQ_POLLED)
type = HCTX_TYPE_POLL;
else if ((flags & REQ_OP_MASK) == REQ_OP_READ)
type = HCTX_TYPE_READ;
return type;
}
/*
* blk_mq_map_queue() - map (cmd_flags,type) to hardware queue
* @q: request queue
* @flags: request command flags
* @ctx: software queue cpu ctx
*/
static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
unsigned int flags,
struct blk_mq_ctx *ctx)
{
return ctx->hctxs[blk_mq_get_hctx_type(flags)];
}
/*
* sysfs helpers
*/
extern void blk_mq_sysfs_init(struct request_queue *q);
extern void blk_mq_sysfs_deinit(struct request_queue *q);
extern int __blk_mq_register_dev(struct device *dev, struct request_queue *q);
extern int blk_mq_sysfs_register(struct request_queue *q);
extern void blk_mq_sysfs_unregister(struct request_queue *q);
extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);
void blk_mq_free_plug_rqs(struct blk_plug *plug);
void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);
void blk_mq_cancel_work_sync(struct request_queue *q);
void blk_mq_release(struct request_queue *q);
static inline struct blk_mq_ctx *__blk_mq_get_ctx(struct request_queue *q,
unsigned int cpu)
{
return per_cpu_ptr(q->queue_ctx, cpu);
}
/*
* This assumes per-cpu software queueing queues. They could be per-node
* as well, for instance. For now this is hardcoded as-is. Note that we don't
* care about preemption, since we know the ctx's are persistent. This does
* mean that we can't rely on ctx always matching the currently running CPU.
*/
static inline struct blk_mq_ctx *blk_mq_get_ctx(struct request_queue *q)
{
return __blk_mq_get_ctx(q, raw_smp_processor_id());
}
struct blk_mq_alloc_data {
/* input parameter */
struct request_queue *q;
blk_mq_req_flags_t flags;
unsigned int shallow_depth;
unsigned int cmd_flags;
req_flags_t rq_flags;
/* allocate multiple requests/tags in one go */
unsigned int nr_tags;
struct request **cached_rq;
/* input & output parameter */
struct blk_mq_ctx *ctx;
struct blk_mq_hw_ctx *hctx;
};
static inline bool blk_mq_is_shared_tags(unsigned int flags)
{
return flags & BLK_MQ_F_TAG_HCTX_SHARED;
}
static inline struct blk_mq_tags *blk_mq_tags_from_data(struct blk_mq_alloc_data *data)
{
if (!(data->rq_flags & RQF_ELV))
return data->hctx->tags;
return data->hctx->sched_tags;
}
static inline bool blk_mq_hctx_stopped(struct blk_mq_hw_ctx *hctx)
{
return test_bit(BLK_MQ_S_STOPPED, &hctx->state);
}
static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
{
return hctx->nr_ctx && hctx->tags;
}
unsigned int blk_mq_in_flight(struct request_queue *q,
struct block_device *part);
void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
unsigned int inflight[2]);
static inline void blk_mq_put_dispatch_budget(struct request_queue *q,
int budget_token)
{
if (q->mq_ops->put_budget)
q->mq_ops->put_budget(q, budget_token);
}
static inline int blk_mq_get_dispatch_budget(struct request_queue *q)
{
if (q->mq_ops->get_budget)
return q->mq_ops->get_budget(q);
return 0;
}
static inline void blk_mq_set_rq_budget_token(struct request *rq, int token)
{
if (token < 0)
return;
if (rq->q->mq_ops->set_rq_budget_token)
rq->q->mq_ops->set_rq_budget_token(rq, token);
}
static inline int blk_mq_get_rq_budget_token(struct request *rq)
{
if (rq->q->mq_ops->get_rq_budget_token)
return rq->q->mq_ops->get_rq_budget_token(rq);
return -1;
}
static inline void __blk_mq_inc_active_requests(struct blk_mq_hw_ctx *hctx)
{
if (blk_mq_is_shared_tags(hctx->flags))
atomic_inc(&hctx->queue->nr_active_requests_shared_tags);
else
atomic_inc(&hctx->nr_active);
}
static inline void __blk_mq_sub_active_requests(struct blk_mq_hw_ctx *hctx,
int val)
{
if (blk_mq_is_shared_tags(hctx->flags))
atomic_sub(val, &hctx->queue->nr_active_requests_shared_tags);
else
atomic_sub(val, &hctx->nr_active);
}
static inline void __blk_mq_dec_active_requests(struct blk_mq_hw_ctx *hctx)
{
__blk_mq_sub_active_requests(hctx, 1);
}
static inline int __blk_mq_active_requests(struct blk_mq_hw_ctx *hctx)
{
if (blk_mq_is_shared_tags(hctx->flags))
return atomic_read(&hctx->queue->nr_active_requests_shared_tags);
return atomic_read(&hctx->nr_active);
}
static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
struct request *rq)
{
blk_mq_put_tag(hctx->tags, rq->mq_ctx, rq->tag);
rq->tag = BLK_MQ_NO_TAG;
if (rq->rq_flags & RQF_MQ_INFLIGHT) {
rq->rq_flags &= ~RQF_MQ_INFLIGHT;
__blk_mq_dec_active_requests(hctx);
}
}
static inline void blk_mq_put_driver_tag(struct request *rq)
{
if (rq->tag == BLK_MQ_NO_TAG || rq->internal_tag == BLK_MQ_NO_TAG)
return;
__blk_mq_put_driver_tag(rq->mq_hctx, rq);
}
bool __blk_mq_get_driver_tag(struct blk_mq_hw_ctx *hctx, struct request *rq);
static inline bool blk_mq_get_driver_tag(struct request *rq)
{
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
if (rq->tag != BLK_MQ_NO_TAG &&
!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
hctx->tags->rqs[rq->tag] = rq;
return true;
}
return __blk_mq_get_driver_tag(hctx, rq);
}
static inline void blk_mq_clear_mq_map(struct blk_mq_queue_map *qmap)
{
int cpu;
for_each_possible_cpu(cpu)
qmap->mq_map[cpu] = 0;
}
/*
* blk_mq_plug() - Get caller context plug
* @q: request queue
* @bio : the bio being submitted by the caller context
*
* Plugging, by design, may delay the insertion of BIOs into the elevator in
* order to increase BIO merging opportunities. This however can cause BIO
* insertion order to change from the order in which submit_bio() is being
* executed in the case of multiple contexts concurrently issuing BIOs to a
* device, even if these context are synchronized to tightly control BIO issuing
* order. While this is not a problem with regular block devices, this ordering
* change can cause write BIO failures with zoned block devices as these
* require sequential write patterns to zones. Prevent this from happening by
* ignoring the plug state of a BIO issuing context if the target request queue
* is for a zoned block device and the BIO to plug is a write operation.
*
* Return current->plug if the bio can be plugged and NULL otherwise
*/
static inline struct blk_plug *blk_mq_plug(struct request_queue *q,
struct bio *bio)
{
/*
* For regular block devices or read operations, use the context plug
* which may be NULL if blk_start_plug() was not executed.
*/
if (!blk_queue_is_zoned(q) || !op_is_write(bio_op(bio)))
return current->plug;
/* Zoned block device write operation case: do not plug the BIO */
return NULL;
}
/* Free all requests on the list */
static inline void blk_mq_free_requests(struct list_head *list)
{
while (!list_empty(list)) {
struct request *rq = list_entry_rq(list->next);
list_del_init(&rq->queuelist);
blk_mq_free_request(rq);
}
}
/*
* For shared tag users, we track the number of currently active users
* and attempt to provide a fair share of the tag depth for each of them.
*/
static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
struct sbitmap_queue *bt)
{
unsigned int depth, users;
if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED))
return true;
/*
* Don't try dividing an ant
*/
if (bt->sb.depth == 1)
return true;
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 true;
} else {
if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
return true;
}
users = atomic_read(&hctx->tags->active_queues);
if (!users)
return true;
/*
* Allow at least some tags
*/
depth = max((bt->sb.depth + users - 1) / users, 4U);
return __blk_mq_active_requests(hctx) < depth;
}
/* run the code block in @dispatch_ops with rcu/srcu read lock held */
#define __blk_mq_run_dispatch_ops(q, check_sleep, dispatch_ops) \
do { \
if (!blk_queue_has_srcu(q)) { \
rcu_read_lock(); \
(dispatch_ops); \
rcu_read_unlock(); \
} else { \
int srcu_idx; \
\
might_sleep_if(check_sleep); \
srcu_idx = srcu_read_lock((q)->srcu); \
(dispatch_ops); \
srcu_read_unlock((q)->srcu, srcu_idx); \
} \
} while (0)
#define blk_mq_run_dispatch_ops(q, dispatch_ops) \
__blk_mq_run_dispatch_ops(q, true, dispatch_ops) \
#endif