blk-mq-sched: provide hooks for initializing hardware queue data

Schedulers need to be informed when a hardware queue is added or removed
at runtime so they can allocate/free per-hardware queue data. So,
replace the blk_mq_sched_init_hctx_data() helper, which only makes sense
at init time, with .init_hctx() and .exit_hctx() hooks.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index c974a1bbf4cbad70ccea464e94d2788c62078dde..9e3c0f92851b2bcfcb6a1740aaefca3a4c00a0a7 100644 (file)
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -30,43 +30,6 @@ void blk_mq_sched_free_hctx_data(struct request_queue *q,
 }
 EXPORT_SYMBOL_GPL(blk_mq_sched_free_hctx_data);
 
-int blk_mq_sched_init_hctx_data(struct request_queue *q, size_t size,
-                               int (*init)(struct blk_mq_hw_ctx *),
-                               void (*exit)(struct blk_mq_hw_ctx *))
-{
-       struct blk_mq_hw_ctx *hctx;
-       int ret;
-       int i;
-
-       queue_for_each_hw_ctx(q, hctx, i) {
-               hctx->sched_data = kmalloc_node(size, GFP_KERNEL, hctx->numa_node);
-               if (!hctx->sched_data) {
-                       ret = -ENOMEM;
-                       goto error;
-               }
-
-               if (init) {
-                       ret = init(hctx);
-                       if (ret) {
-                               /*
-                                * We don't want to give exit() a partially
-                                * initialized sched_data. init() must clean up
-                                * if it fails.
-                                */
-                               kfree(hctx->sched_data);
-                               hctx->sched_data = NULL;
-                               goto error;
-                       }
-               }
-       }
-
-       return 0;
-error:
-       blk_mq_sched_free_hctx_data(q, exit);
-       return ret;
-}
-EXPORT_SYMBOL_GPL(blk_mq_sched_init_hctx_data);
-
 static void __blk_mq_sched_assign_ioc(struct request_queue *q,
                                      struct request *rq,
                                      struct bio *bio,
@@ -508,11 +471,24 @@ int blk_mq_sched_init_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
                           unsigned int hctx_idx)
 {
        struct elevator_queue *e = q->elevator;
+       int ret;
 
        if (!e)
                return 0;
 
-       return blk_mq_sched_alloc_tags(q, hctx, hctx_idx);
+       ret = blk_mq_sched_alloc_tags(q, hctx, hctx_idx);
+       if (ret)
+               return ret;
+
+       if (e->type->ops.mq.init_hctx) {
+               ret = e->type->ops.mq.init_hctx(hctx, hctx_idx);
+               if (ret) {
+                       blk_mq_sched_free_tags(q->tag_set, hctx, hctx_idx);
+                       return ret;
+               }
+       }
+
+       return 0;
 }
 
 void blk_mq_sched_exit_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
@@ -523,12 +499,18 @@ void blk_mq_sched_exit_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
        if (!e)
                return;
 
+       if (e->type->ops.mq.exit_hctx && hctx->sched_data) {
+               e->type->ops.mq.exit_hctx(hctx, hctx_idx);
+               hctx->sched_data = NULL;
+       }
+
        blk_mq_sched_free_tags(q->tag_set, hctx, hctx_idx);
 }
 
 int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
 {
        struct blk_mq_hw_ctx *hctx;
+       struct elevator_queue *eq;
        unsigned int i;
        int ret;
 
@@ -553,6 +535,18 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
        if (ret)
                goto err;
 
+       if (e->ops.mq.init_hctx) {
+               queue_for_each_hw_ctx(q, hctx, i) {
+                       ret = e->ops.mq.init_hctx(hctx, i);
+                       if (ret) {
+                               eq = q->elevator;
+                               blk_mq_exit_sched(q, eq);
+                               kobject_put(&eq->kobj);
+                               return ret;
+                       }
+               }
+       }
+
        return 0;
 
 err:
@@ -563,6 +557,17 @@ err:
 
 void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e)
 {
+       struct blk_mq_hw_ctx *hctx;
+       unsigned int i;
+
+       if (e->type->ops.mq.exit_hctx) {
+               queue_for_each_hw_ctx(q, hctx, i) {
+                       if (hctx->sched_data) {
+                               e->type->ops.mq.exit_hctx(hctx, i);
+                               hctx->sched_data = NULL;
+                       }
+               }
+       }
        if (e->type->ops.mq.exit_sched)
                e->type->ops.mq.exit_sched(e);
        blk_mq_sched_tags_teardown(q);

diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
index 3a9e6e40558b599dee22115be54f5f7ce9f11080..f4bc186c34409052ba8c0778ee37c5c16179cae6 100644 (file)
--- a/block/blk-mq-sched.h
+++ b/block/blk-mq-sched.h
@@ -4,10 +4,6 @@
 #include "blk-mq.h"
 #include "blk-mq-tag.h"
 
-int blk_mq_sched_init_hctx_data(struct request_queue *q, size_t size,
-                               int (*init)(struct blk_mq_hw_ctx *),
-                               void (*exit)(struct blk_mq_hw_ctx *));
-
 void blk_mq_sched_free_hctx_data(struct request_queue *q,
                                 void (*exit)(struct blk_mq_hw_ctx *));
 

diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index 22d39e8d4de16be2b69762cf24c92799dfb445d6..b7ec315ee7e759cad0ea8effb94214b1ec569519 100644 (file)
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -93,6 +93,8 @@ struct blk_mq_hw_ctx;
 struct elevator_mq_ops {
        int (*init_sched)(struct request_queue *, struct elevator_type *);
        void (*exit_sched)(struct elevator_queue *);
+       int (*init_hctx)(struct blk_mq_hw_ctx *, unsigned int);
+       void (*exit_hctx)(struct blk_mq_hw_ctx *, unsigned int);
 
        bool (*allow_merge)(struct request_queue *, struct request *, struct bio *);
        bool (*bio_merge)(struct blk_mq_hw_ctx *, struct bio *);