mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-14 15:54:15 +08:00
157f377beb
A NULL pointer crash was reported for the case of having the BFQ IO scheduler attached to the underlying blk-mq paths of a DM multipath device. The crash occured in blk_mq_sched_insert_request()'s call to e->type->ops.mq.insert_requests(). Paolo Valente correctly summarized why the crash occured with: "the call chain (dm_mq_queue_rq -> map_request -> setup_clone -> blk_rq_prep_clone) creates a cloned request without invoking e->type->ops.mq.prepare_request for the target elevator e. The cloned request is therefore not initialized for the scheduler, but it is however inserted into the scheduler by blk_mq_sched_insert_request." All said, a request-based DM multipath device's IO scheduler should be the only one used -- when the original requests are issued to the underlying paths as cloned requests they are inserted directly in the underlying dispatch queue(s) rather than through an additional elevator. But commitbd166ef18("blk-mq-sched: add framework for MQ capable IO schedulers") switched blk_insert_cloned_request() from using blk_mq_insert_request() to blk_mq_sched_insert_request(). Which incorrectly added elevator machinery into a call chain that isn't supposed to have any. To fix this introduce a blk-mq private blk_mq_request_bypass_insert() that blk_insert_cloned_request() calls to insert the request without involving any elevator that may be attached to the cloned request's request_queue. Fixes:bd166ef183("blk-mq-sched: add framework for MQ capable IO schedulers") Cc: stable@vger.kernel.org Reported-by: Bart Van Assche <Bart.VanAssche@wdc.com> Tested-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
141 lines
4.0 KiB
C
141 lines
4.0 KiB
C
#ifndef INT_BLK_MQ_H
|
|
#define INT_BLK_MQ_H
|
|
|
|
#include "blk-stat.h"
|
|
|
|
struct blk_mq_tag_set;
|
|
|
|
struct blk_mq_ctx {
|
|
struct {
|
|
spinlock_t lock;
|
|
struct list_head rq_list;
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
unsigned int cpu;
|
|
unsigned int index_hw;
|
|
|
|
/* incremented at dispatch time */
|
|
unsigned long rq_dispatched[2];
|
|
unsigned long rq_merged;
|
|
|
|
/* incremented at completion time */
|
|
unsigned long ____cacheline_aligned_in_smp rq_completed[2];
|
|
|
|
struct request_queue *queue;
|
|
struct kobject kobj;
|
|
} ____cacheline_aligned_in_smp;
|
|
|
|
void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async);
|
|
void blk_mq_freeze_queue(struct request_queue *q);
|
|
void blk_mq_free_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 request_queue *, struct list_head *);
|
|
void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list);
|
|
bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx);
|
|
bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx,
|
|
bool wait);
|
|
|
|
/*
|
|
* 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_rq_map(struct blk_mq_tag_set *set,
|
|
unsigned int hctx_idx,
|
|
unsigned int nr_tags,
|
|
unsigned int reserved_tags);
|
|
int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
|
|
unsigned int hctx_idx, unsigned int depth);
|
|
|
|
/*
|
|
* 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);
|
|
void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
|
|
struct list_head *list);
|
|
|
|
/*
|
|
* CPU -> queue mappings
|
|
*/
|
|
extern int blk_mq_hw_queue_to_node(unsigned int *map, unsigned int);
|
|
|
|
static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q,
|
|
int cpu)
|
|
{
|
|
return q->queue_hw_ctx[q->mq_map[cpu]];
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
|
|
extern void blk_mq_rq_timed_out(struct request *req, bool reserved);
|
|
|
|
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, get_cpu());
|
|
}
|
|
|
|
static inline void blk_mq_put_ctx(struct blk_mq_ctx *ctx)
|
|
{
|
|
put_cpu();
|
|
}
|
|
|
|
struct blk_mq_alloc_data {
|
|
/* input parameter */
|
|
struct request_queue *q;
|
|
unsigned int flags;
|
|
unsigned int shallow_depth;
|
|
|
|
/* input & output parameter */
|
|
struct blk_mq_ctx *ctx;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
};
|
|
|
|
static inline struct blk_mq_tags *blk_mq_tags_from_data(struct blk_mq_alloc_data *data)
|
|
{
|
|
if (data->flags & BLK_MQ_REQ_INTERNAL)
|
|
return data->hctx->sched_tags;
|
|
|
|
return data->hctx->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;
|
|
}
|
|
|
|
void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part,
|
|
unsigned int inflight[2]);
|
|
|
|
#endif
|