[PATCH 25/30] block: remove request_list code

Jens Axboe
2018-10-31T17:59:17Z

It's now dead code, nobody uses it.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
block/blk-cgroup.c | 47 ----------------
block/blk-core.c | 75 --------------------------
block/blk-mq.c | 4 --
block/blk.h | 3 --
include/linux/blk-cgroup.h | 108 -------------------------------------
include/linux/blkdev.h | 34 ------------
6 files changed, 271 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 5f10d755ec52..020869a37d11 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -76,9 +76,6 @@ static void blkg_free(struct blkcg_gq *blkg)
if (blkg->pd[i])
blkcg_policy[i]->pd_free_fn(blkg->pd[i]);

- if (blkg->blkcg != &blkcg_root)
- blk_exit_rl(blkg->q, &blkg->rl);
-
blkg_rwstat_exit(&blkg->stat_ios);
blkg_rwstat_exit(&blkg->stat_bytes);
kfree(blkg);
@@ -142,13 +139,6 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q,
INIT_LIST_HEAD(&blkg->q_node);
blkg->blkcg = blkcg;

- /* root blkg uses @q->root_rl, init rl only for !root blkgs */
- if (blkcg != &blkcg_root) {
- if (blk_init_rl(&blkg->rl, q, gfp_mask))
- goto err_free;
- blkg->rl.blkg = blkg;
- }
-
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
struct blkg_policy_data *pd;
@@ -448,42 +438,6 @@ static void blkg_destroy_all(struct request_queue *q)
}

q->root_blkg = NULL;
- q->root_rl.blkg = NULL;
-}
-
-/*
- * The next function used by blk_queue_for_each_rl(). It's a bit tricky
- * because the root blkg uses @q->root_rl instead of its own rl.
- */
-struct request_list *__blk_queue_next_rl(struct request_list *rl,
- struct request_queue *q)
-{
- struct list_head *ent;
- struct blkcg_gq *blkg;
-
- /*
- * Determine the current blkg list_head. The first entry is
- * root_rl which is off @q->blkg_list and mapped to the head.
- */
- if (rl == &q->root_rl) {
- ent = &q->blkg_list;
- /* There are no more block groups, hence no request lists */
- if (list_empty(ent))
- return NULL;
- } else {
- blkg = container_of(rl, struct blkcg_gq, rl);
- ent = &blkg->q_node;
- }
-
- /* walk to the next list_head, skip root blkcg */
- ent = ent->next;
- if (ent == &q->root_blkg->q_node)
- ent = ent->next;
- if (ent == &q->blkg_list)
- return NULL;
-
- blkg = container_of(ent, struct blkcg_gq, q_node);
- return &blkg->rl;
}

static int blkcg_reset_stats(struct cgroup_subsys_state *css,
@@ -1278,7 +1232,6 @@ int blkcg_init_queue(struct request_queue *q)
if (IS_ERR(blkg))
goto err_unlock;
q->root_blkg = blkg;
- q->root_rl.blkg = blkg;
spin_unlock_irq(q->queue_lock);
rcu_read_unlock();

diff --git a/block/blk-core.c b/block/blk-core.c
index fcdb631f0a7a..0678ec4b1169 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -447,81 +447,6 @@ void blk_cleanup_queue(struct request_queue *q)
}
EXPORT_SYMBOL(blk_cleanup_queue);

-/* Allocate memory local to the request queue */
-static void *alloc_request_simple(gfp_t gfp_mask, void *data)
-{
- struct request_queue *q = data;
-
- return kmem_cache_alloc_node(request_cachep, gfp_mask, q->node);
-}
-
-static void free_request_simple(void *element, void *data)
-{
- kmem_cache_free(request_cachep, element);
-}
-
-static void *alloc_request_size(gfp_t gfp_mask, void *data)
-{
- struct request_queue *q = data;
- struct request *rq;
-
- rq = kmalloc_node(sizeof(struct request) + q->cmd_size, gfp_mask,
- q->node);
- if (rq && q->init_rq_fn && q->init_rq_fn(q, rq, gfp_mask) < 0) {
- kfree(rq);
- rq = NULL;
- }
- return rq;
-}
-
-static void free_request_size(void *element, void *data)
-{
- struct request_queue *q = data;
-
- if (q->exit_rq_fn)
- q->exit_rq_fn(q, element);
- kfree(element);
-}
-
-int blk_init_rl(struct request_list *rl, struct request_queue *q,
- gfp_t gfp_mask)
-{
- if (unlikely(rl->rq_pool) || q->mq_ops)
- return 0;
-
- rl->q = q;
- rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
- rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
- init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
- init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
-
- if (q->cmd_size) {
- rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ,
- alloc_request_size, free_request_size,
- q, gfp_mask, q->node);
- } else {
- rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ,
- alloc_request_simple, free_request_simple,
- q, gfp_mask, q->node);
- }
- if (!rl->rq_pool)
- return -ENOMEM;
-
- if (rl != &q->root_rl)
- WARN_ON_ONCE(!blk_get_queue(q));
-
- return 0;
-}
-
-void blk_exit_rl(struct request_queue *q, struct request_list *rl)
-{
- if (rl->rq_pool) {
- mempool_destroy(rl->rq_pool);
- if (rl != &q->root_rl)
- blk_put_queue(q);
- }
-}
-
struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
{
return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE, NULL);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a58d2d953876..d43c9232c77c 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -326,10 +326,6 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
rq->end_io_data = NULL;
rq->next_rq = NULL;

-#ifdef CONFIG_BLK_CGROUP
- rq->rl = NULL;
-#endif
-
data->ctx->rq_dispatched[op_is_sync(op)]++;
refcount_set(&rq->ref, 1);
return rq;
diff --git a/block/blk.h b/block/blk.h
index 4ae6cacb4548..e925cf4fe4de 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -120,9 +120,6 @@ struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q,
int node, int cmd_size, gfp_t flags);
void blk_free_flush_queue(struct blk_flush_queue *q);

-int blk_init_rl(struct request_list *rl, struct request_queue *q,
- gfp_t gfp_mask);
-void blk_exit_rl(struct request_queue *q, struct request_list *rl);
void blk_exit_queue(struct request_queue *q);
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio);
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 1e76ceebeb5d..f2c067071336 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -122,9 +122,6 @@ struct blkcg_gq {
/* all non-root blkcg_gq's are guaranteed to have access to parent */
struct blkcg_gq *parent;

- /* request allocation list for this blkcg-q pair */
- struct request_list rl;
-
/* reference count */
struct percpu_ref refcnt;

@@ -561,105 +558,6 @@ static inline void blkg_put(struct blkcg_gq *blkg)
if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
(p_blkg)->q, false)))

-/**
- * blk_get_rl - get request_list to use
- * @q: request_queue of interest
- * @bio: bio which will be attached to the allocated request (may be %NULL)
- *
- * The caller wants to allocate a request from @q to use for @bio. Find
- * the request_list to use and obtain a reference on it. Should be called
- * under queue_lock. This function is guaranteed to return non-%NULL
- * request_list.
- */
-static inline struct request_list *blk_get_rl(struct request_queue *q,
- struct bio *bio)
-{
- struct blkcg *blkcg;
- struct blkcg_gq *blkg;
-
- rcu_read_lock();
-
- if (bio && bio->bi_blkg) {
- blkcg = bio->bi_blkg->blkcg;
- if (blkcg == &blkcg_root)
- goto rl_use_root;
-
- blkg_get(bio->bi_blkg);
- rcu_read_unlock();
- return &bio->bi_blkg->rl;
- }
-
- blkcg = css_to_blkcg(blkcg_css());
- if (blkcg == &blkcg_root)
- goto rl_use_root;
-
- blkg = blkg_lookup(blkcg, q);
- if (unlikely(!blkg))
- blkg = __blkg_lookup_create(blkcg, q);
-
- if (blkg->blkcg == &blkcg_root || !blkg_tryget(blkg))
- goto rl_use_root;
-
- rcu_read_unlock();
- return &blkg->rl;
-
- /*
- * Each blkg has its own request_list, however, the root blkcg
- * uses the request_queue's root_rl. This is to avoid most
- * overhead for the root blkcg.
- */
-rl_use_root:
- rcu_read_unlock();
- return &q->root_rl;
-}
-
-/**
- * blk_put_rl - put request_list
- * @rl: request_list to put
- *
- * Put the reference acquired by blk_get_rl(). Should be called under
- * queue_lock.
- */
-static inline void blk_put_rl(struct request_list *rl)
-{
- if (rl->blkg->blkcg != &blkcg_root)
- blkg_put(rl->blkg);
-}
-
-/**
- * blk_rq_set_rl - associate a request with a request_list
- * @rq: request of interest
- * @rl: target request_list
- *
- * Associate @rq with @rl so that accounting and freeing can know the
- * request_list @rq came from.
- */
-static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
-{
- rq->rl = rl;
-}
-
-/**
- * blk_rq_rl - return the request_list a request came from
- * @rq: request of interest
- *
- * Return the request_list @rq is allocated from.
- */
-static inline struct request_list *blk_rq_rl(struct request *rq)
-{
- return rq->rl;
-}
-
-struct request_list *__blk_queue_next_rl(struct request_list *rl,
- struct request_queue *q);
-/**
- * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
- *
- * Should be used under queue_lock.
- */
-#define blk_queue_for_each_rl(rl, q) \
- for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
-
static inline int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp)
{
int ret;
@@ -993,12 +891,6 @@ static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
static inline void blkg_get(struct blkcg_gq *blkg) { }
static inline void blkg_put(struct blkcg_gq *blkg) { }

-static inline struct request_list *blk_get_rl(struct request_queue *q,
- struct bio *bio) { return &q->root_rl; }
-static inline void blk_put_rl(struct request_list *rl) { }
-static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
-static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
-
static inline void blkcg_bio_issue_init(struct bio *bio) { }
static inline bool blkcg_bio_issue_check(struct request_queue *q,
struct bio *bio) { return true; }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 877a3d235c45..e0c661a95c39 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -58,22 +58,6 @@ struct blk_stat_callback;

typedef void (rq_end_io_fn)(struct request *, blk_status_t);

-struct request_list {
- struct request_queue *q; /* the queue this rl belongs to */
-#ifdef CONFIG_BLK_CGROUP
- struct blkcg_gq *blkg; /* blkg this request pool belongs to */
-#endif
- /*
- * count[], starved[], and wait[] are indexed by
- * BLK_RW_SYNC/BLK_RW_ASYNC
- */
- int count[2];
- int starved[2];
- mempool_t *rq_pool;
- wait_queue_head_t wait[2];
- unsigned int flags;
-};
-
/*
* request flags */
typedef __u32 __bitwise req_flags_t;
@@ -259,10 +243,6 @@ struct request {

/* for bidi */
struct request *next_rq;
-
-#ifdef CONFIG_BLK_CGROUP
- struct request_list *rl; /* rl this rq is alloced from */
-#endif
};

static inline bool blk_op_is_scsi(unsigned int op)
@@ -312,8 +292,6 @@ typedef bool (poll_q_fn) (struct request_queue *q, blk_qc_t);
struct bio_vec;
typedef void (softirq_done_fn)(struct request *);
typedef int (dma_drain_needed_fn)(struct request *);
-typedef int (init_rq_fn)(struct request_queue *, struct request *, gfp_t);
-typedef void (exit_rq_fn)(struct request_queue *, struct request *);

enum blk_eh_timer_return {
BLK_EH_DONE, /* drivers has completed the command */
@@ -427,22 +405,10 @@ struct request_queue {
struct blk_queue_stats *stats;
struct rq_qos *rq_qos;

- /*
- * If blkcg is not used, @q->root_rl serves all requests. If blkcg
- * is used, root blkg allocates from @q->root_rl and all other
- * blkgs from their own blkg->rl. Which one to use should be
- * determined using bio_request_list().
- */
- struct request_list root_rl;
-
make_request_fn *make_request_fn;
poll_q_fn *poll_fn;
softirq_done_fn *softirq_done_fn;
dma_drain_needed_fn *dma_drain_needed;
- /* Called just after a request is allocated */
- init_rq_fn *init_rq_fn;
- /* Called just before a request is freed */
- exit_rq_fn *exit_rq_fn;

const struct blk_mq_ops *mq_ops;

--
2.17.1