block: prepare for multiple request_lists

Request allocation is about to be made per-blkg meaning that there'll
be multiple request lists.

* Make queue full state per request_list.  blk_*queue_full() functions
  are renamed to blk_*rl_full() and takes @rl instead of @q.

* Rename blk_init_free_list() to blk_init_rl() and make it take @rl
  instead of @q.  Also add @gfp_mask parameter.

* Add blk_exit_rl() instead of destroying rl directly from
  blk_release_queue().

* Add request_list->q and make request alloc/free functions -
  blk_free_request(), [__]freed_request(), __get_request() - take @rl
  instead of @q.

This patch doesn't introduce any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 39 insertions, 32 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index a2648153691f..f392a2edf462 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -517,13 +517,13 @@ void blk_cleanup_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_cleanup_queue);
 
-static int blk_init_free_list(struct request_queue *q)
+int blk_init_rl(struct request_list *rl, struct request_queue *q,
+                gfp_t gfp_mask)
 {
-        struct request_list *rl = &q->rq;
-
         if (unlikely(rl->rq_pool))
                 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]);
@@ -531,13 +531,19 @@ static int blk_init_free_list(struct request_queue *q)
 
         rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
                                           mempool_free_slab, request_cachep,
-                                          GFP_KERNEL, q->node);
+                                          gfp_mask, q->node);
         if (!rl->rq_pool)
                 return -ENOMEM;
 
         return 0;
 }
 
+void blk_exit_rl(struct request_list *rl)
+{
+        if (rl->rq_pool)
+                mempool_destroy(rl->rq_pool);
+}
+
 struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
 {
         return blk_alloc_queue_node(gfp_mask, -1);
@@ -679,7 +685,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
         if (!q)
                 return NULL;
 
-        if (blk_init_free_list(q))
+        if (blk_init_rl(&q->rq, q, GFP_KERNEL))
                 return NULL;
 
         q->request_fn           = rfn;
@@ -721,15 +727,15 @@ bool blk_get_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_get_queue);
 
-static inline void blk_free_request(struct request_queue *q, struct request *rq)
+static inline void blk_free_request(struct request_list *rl, struct request *rq)
 {
         if (rq->cmd_flags & REQ_ELVPRIV) {
-                elv_put_request(q, rq);
+                elv_put_request(rl->q, rq);
                 if (rq->elv.icq)
                         put_io_context(rq->elv.icq->ioc);
         }
 
-        mempool_free(rq, q->rq.rq_pool);
+        mempool_free(rq, rl->rq_pool);
 }
 
 /*
@@ -766,9 +772,9 @@ static void ioc_set_batching(struct request_queue *q, struct io_context *ioc)
         ioc->last_waited = jiffies;
 }
 
-static void __freed_request(struct request_queue *q, int sync)
+static void __freed_request(struct request_list *rl, int sync)
 {
-        struct request_list *rl = &q->rq;
+        struct request_queue *q = rl->q;
 
         if (rl->count[sync] < queue_congestion_off_threshold(q))
                 blk_clear_queue_congested(q, sync);
@@ -777,7 +783,7 @@ static void __freed_request(struct request_queue *q, int sync)
                 if (waitqueue_active(&rl->wait[sync]))
                         wake_up(&rl->wait[sync]);
 
-                blk_clear_queue_full(q, sync);
+                blk_clear_rl_full(rl, sync);
         }
 }
 
@@ -785,9 +791,9 @@ static void __freed_request(struct request_queue *q, int sync)
  * A request has just been released.  Account for it, update the full and
  * congestion status, wake up any waiters.   Called under q->queue_lock.
  */
-static void freed_request(struct request_queue *q, unsigned int flags)
+static void freed_request(struct request_list *rl, unsigned int flags)
 {
-        struct request_list *rl = &q->rq;
+        struct request_queue *q = rl->q;
         int sync = rw_is_sync(flags);
 
         q->nr_rqs[sync]--;
@@ -795,10 +801,10 @@ static void freed_request(struct request_queue *q, unsigned int flags)
         if (flags & REQ_ELVPRIV)
                 q->nr_rqs_elvpriv--;
 
-        __freed_request(q, sync);
+        __freed_request(rl, sync);
 
         if (unlikely(rl->starved[sync ^ 1]))
-                __freed_request(q, sync ^ 1);
+                __freed_request(rl, sync ^ 1);
 }
 
 /*
@@ -838,7 +844,7 @@ static struct io_context *rq_ioc(struct bio *bio)
 
 /**
  * __get_request - get a free request
- * @q: request_queue to allocate request from
+ * @rl: request list to allocate from
  * @rw_flags: RW and SYNC flags
  * @bio: bio to allocate request for (can be %NULL)
  * @gfp_mask: allocation mask
@@ -850,11 +856,11 @@ static struct io_context *rq_ioc(struct bio *bio)
  * Returns %NULL on failure, with @q->queue_lock held.
  * Returns !%NULL on success, with @q->queue_lock *not held*.
  */
-static struct request *__get_request(struct request_queue *q, int rw_flags,
+static struct request *__get_request(struct request_list *rl, int rw_flags,
                                      struct bio *bio, gfp_t gfp_mask)
 {
+        struct request_queue *q = rl->q;
         struct request *rq;
-        struct request_list *rl = &q->rq;
         struct elevator_type *et = q->elevator->type;
         struct io_context *ioc = rq_ioc(bio);
         struct io_cq *icq = NULL;
@@ -876,9 +882,9 @@ static struct request *__get_request(struct request_queue *q, int rw_flags,
                          * This process will be allowed to complete a batch of
                          * requests, others will be blocked.
                          */
-                        if (!blk_queue_full(q, is_sync)) {
+                        if (!blk_rl_full(rl, is_sync)) {
                                 ioc_set_batching(q, ioc);
-                                blk_set_queue_full(q, is_sync);
+                                blk_set_rl_full(rl, is_sync);
                         } else {
                                 if (may_queue != ELV_MQUEUE_MUST
                                                 && !ioc_batching(q, ioc)) {
@@ -928,7 +934,7 @@ static struct request *__get_request(struct request_queue *q, int rw_flags,
         spin_unlock_irq(q->queue_lock);
 
         /* allocate and init request */
-        rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
+        rq = mempool_alloc(rl->rq_pool, gfp_mask);
         if (!rq)
                 goto fail_alloc;
 
@@ -992,7 +998,7 @@ fail_alloc:
          * queue, but this is pretty rare.
          */
         spin_lock_irq(q->queue_lock);
-        freed_request(q, rw_flags);
+        freed_request(rl, rw_flags);
 
         /*
          * in the very unlikely event that allocation failed and no
@@ -1029,7 +1035,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
         struct request_list *rl = &q->rq;
         struct request *rq;
 retry:
-        rq = __get_request(q, rw_flags, bio, gfp_mask);
+        rq = __get_request(&q->rq, rw_flags, bio, gfp_mask);
         if (rq)
                 return rq;
 
@@ -1229,8 +1235,8 @@ void __blk_put_request(struct request_queue *q, struct request *req)
                 BUG_ON(!list_empty(&req->queuelist));
                 BUG_ON(!hlist_unhashed(&req->hash));
 
-                blk_free_request(q, req);
-                freed_request(q, flags);
+                blk_free_request(&q->rq, req);
+                freed_request(&q->rq, flags);
         }
 }
 EXPORT_SYMBOL_GPL(__blk_put_request);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index aa41b47c22d2..234ce7c082fa 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -66,16 +66,16 @@ queue_requests_store(struct request_queue *q, const char *page, size_t count)
                 blk_clear_queue_congested(q, BLK_RW_ASYNC);
 
         if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
-                blk_set_queue_full(q, BLK_RW_SYNC);
+                blk_set_rl_full(rl, BLK_RW_SYNC);
         } else {
-                blk_clear_queue_full(q, BLK_RW_SYNC);
+                blk_clear_rl_full(rl, BLK_RW_SYNC);
                 wake_up(&rl->wait[BLK_RW_SYNC]);
         }
 
         if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
-                blk_set_queue_full(q, BLK_RW_ASYNC);
+                blk_set_rl_full(rl, BLK_RW_ASYNC);
         } else {
-                blk_clear_queue_full(q, BLK_RW_ASYNC);
+                blk_clear_rl_full(rl, BLK_RW_ASYNC);
                 wake_up(&rl->wait[BLK_RW_ASYNC]);
         }
         spin_unlock_irq(q->queue_lock);
@@ -476,7 +476,6 @@ static void blk_release_queue(struct kobject *kobj)
 {
         struct request_queue *q =
                 container_of(kobj, struct request_queue, kobj);
-        struct request_list *rl = &q->rq;
 
         blk_sync_queue(q);
 
@@ -489,8 +488,7 @@ static void blk_release_queue(struct kobject *kobj)
                 elevator_exit(q->elevator);
         }
 
-        if (rl->rq_pool)
-                mempool_destroy(rl->rq_pool);
+        blk_exit_rl(&q->rq);
 
         if (q->queue_tags)
                 __blk_queue_free_tags(q);
diff --git a/block/blk.h b/block/blk.h
index 85f6ae42f7d3..a134231fd22a 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -18,6 +18,9 @@ static inline void __blk_get_queue(struct request_queue *q)
         kobject_get(&q->kobj);
 }
 
+int blk_init_rl(struct request_list *rl, struct request_queue *q,
+                gfp_t gfp_mask);
+void blk_exit_rl(struct request_list *rl);
 void init_request_from_bio(struct request *req, struct bio *bio);
 void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
                         struct bio *bio);