blk-mq: untangle debugfs and sysfs

[mirror_ubuntu-bionic-kernel.git] / block / blk-mq-debugfs.c

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 1dc1847b53636c2f69f64ec183229609982110e4..260cf76e0705d2a998715b1565c13a0863e785ee 100644 (file)
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -687,19 +687,46 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
        {},
 };
 
+static bool debugfs_create_files(struct dentry *parent, void *data,
+                                const struct blk_mq_debugfs_attr *attr)
+{
+       d_inode(parent)->i_private = data;
+
+       for (; attr->name; attr++) {
+               if (!debugfs_create_file(attr->name, attr->mode, parent,
+                                        (void *)attr, &blk_mq_debugfs_fops))
+                       return false;
+       }
+       return true;
+}
+
 int blk_mq_debugfs_register(struct request_queue *q)
 {
+       struct blk_mq_hw_ctx *hctx;
+       int i;
+
        if (!blk_debugfs_root)
                return -ENOENT;
 
        q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
                                            blk_debugfs_root);
        if (!q->debugfs_dir)
-               goto err;
+               return -ENOMEM;
 
-       if (blk_mq_debugfs_register_mq(q))
+       if (!debugfs_create_files(q->debugfs_dir, q,
+                                 blk_mq_debugfs_queue_attrs))
                goto err;
 
+       /*
+        * blk_mq_init_hctx() attempted to do this already, but q->debugfs_dir
+        * didn't exist yet (because we don't know what to name the directory
+        * until the queue is registered to a gendisk).
+        */
+       queue_for_each_hw_ctx(q, hctx, i) {
+               if (!hctx->debugfs_dir && blk_mq_debugfs_register_hctx(q, hctx))
+                       goto err;
+       }
+
        return 0;
 
 err:
@@ -710,32 +737,17 @@ err:
 void blk_mq_debugfs_unregister(struct request_queue *q)
 {
        debugfs_remove_recursive(q->debugfs_dir);
-       q->mq_debugfs_dir = NULL;
        q->debugfs_dir = NULL;
 }
 
-static bool debugfs_create_files(struct dentry *parent, void *data,
-                                const struct blk_mq_debugfs_attr *attr)
-{
-       d_inode(parent)->i_private = data;
-
-       for (; attr->name; attr++) {
-               if (!debugfs_create_file(attr->name, attr->mode, parent,
-                                        (void *)attr, &blk_mq_debugfs_fops))
-                       return false;
-       }
-       return true;
-}
-
-static int blk_mq_debugfs_register_ctx(struct request_queue *q,
-                                      struct blk_mq_ctx *ctx,
-                                      struct dentry *hctx_dir)
+static int blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
+                                      struct blk_mq_ctx *ctx)
 {
        struct dentry *ctx_dir;
        char name[20];
 
        snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
-       ctx_dir = debugfs_create_dir(name, hctx_dir);
+       ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
        if (!ctx_dir)
                return -ENOMEM;
 
@@ -745,59 +757,61 @@ static int blk_mq_debugfs_register_ctx(struct request_queue *q,
        return 0;
 }
 
-static int blk_mq_debugfs_register_hctx(struct request_queue *q,
-                                       struct blk_mq_hw_ctx *hctx)
+int blk_mq_debugfs_register_hctx(struct request_queue *q,
+                                struct blk_mq_hw_ctx *hctx)
 {
        struct blk_mq_ctx *ctx;
-       struct dentry *hctx_dir;
        char name[20];
        int i;
 
+       if (!q->debugfs_dir)
+               return -ENOENT;
+
        snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
-       hctx_dir = debugfs_create_dir(name, q->mq_debugfs_dir);
-       if (!hctx_dir)
+       hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
+       if (!hctx->debugfs_dir)
                return -ENOMEM;
 
-       if (!debugfs_create_files(hctx_dir, hctx, blk_mq_debugfs_hctx_attrs))
-               return -ENOMEM;
+       if (!debugfs_create_files(hctx->debugfs_dir, hctx,
+                                 blk_mq_debugfs_hctx_attrs))
+               goto err;
 
        hctx_for_each_ctx(hctx, ctx, i) {
-               if (blk_mq_debugfs_register_ctx(q, ctx, hctx_dir))
-                       return -ENOMEM;
+               if (blk_mq_debugfs_register_ctx(hctx, ctx))
+                       goto err;
        }
 
        return 0;
+
+err:
+       blk_mq_debugfs_unregister_hctx(hctx);
+       return -ENOMEM;
+}
+
+void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
+{
+       debugfs_remove_recursive(hctx->debugfs_dir);
+       hctx->debugfs_dir = NULL;
 }
 
-int blk_mq_debugfs_register_mq(struct request_queue *q)
+int blk_mq_debugfs_register_hctxs(struct request_queue *q)
 {
        struct blk_mq_hw_ctx *hctx;
        int i;
 
-       if (!q->debugfs_dir)
-               return -ENOENT;
-
-       q->mq_debugfs_dir = debugfs_create_dir("mq", q->debugfs_dir);
-       if (!q->mq_debugfs_dir)
-               goto err;
-
-       if (!debugfs_create_files(q->mq_debugfs_dir, q, blk_mq_debugfs_queue_attrs))
-               goto err;
-
        queue_for_each_hw_ctx(q, hctx, i) {
                if (blk_mq_debugfs_register_hctx(q, hctx))
-                       goto err;
+                       return -ENOMEM;
        }
 
        return 0;
-
-err:
-       blk_mq_debugfs_unregister_mq(q);
-       return -ENOMEM;
 }
 
-void blk_mq_debugfs_unregister_mq(struct request_queue *q)
+void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
 {
-       debugfs_remove_recursive(q->mq_debugfs_dir);
-       q->mq_debugfs_dir = NULL;
+       struct blk_mq_hw_ctx *hctx;
+       int i;
+
+       queue_for_each_hw_ctx(q, hctx, i)
+               blk_mq_debugfs_unregister_hctx(hctx);
 }