From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file

---
 kernel/block/blk-mq-sysfs.c |   94 +++++++++++++++++++++++------------------------
 1 files changed, 46 insertions(+), 48 deletions(-)

diff --git a/kernel/block/blk-mq-sysfs.c b/kernel/block/blk-mq-sysfs.c
index 5006a0d..f0bc339 100644
--- a/kernel/block/blk-mq-sysfs.c
+++ b/kernel/block/blk-mq-sysfs.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/backing-dev.h>
@@ -16,6 +17,18 @@
 
 static void blk_mq_sysfs_release(struct kobject *kobj)
 {
+	struct blk_mq_ctxs *ctxs = container_of(kobj, struct blk_mq_ctxs, kobj);
+
+	free_percpu(ctxs->queue_ctx);
+	kfree(ctxs);
+}
+
+static void blk_mq_ctx_sysfs_release(struct kobject *kobj)
+{
+	struct blk_mq_ctx *ctx = container_of(kobj, struct blk_mq_ctx, kobj);
+
+	/* ctx->ctxs won't be released until all ctx are freed */
+	kobject_put(&ctx->ctxs->kobj);
 }
 
 static void blk_mq_hw_sysfs_release(struct kobject *kobj)
@@ -59,10 +72,8 @@
 	if (!entry->show)
 		return -EIO;
 
-	res = -ENOENT;
 	mutex_lock(&q->sysfs_lock);
-	if (!blk_queue_dying(q))
-		res = entry->show(ctx, page);
+	res = entry->show(ctx, page);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
 }
@@ -82,10 +93,8 @@
 	if (!entry->store)
 		return -EIO;
 
-	res = -ENOENT;
 	mutex_lock(&q->sysfs_lock);
-	if (!blk_queue_dying(q))
-		res = entry->store(ctx, page, length);
+	res = entry->store(ctx, page, length);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
 }
@@ -105,10 +114,8 @@
 	if (!entry->show)
 		return -EIO;
 
-	res = -ENOENT;
 	mutex_lock(&q->sysfs_lock);
-	if (!blk_queue_dying(q))
-		res = entry->show(hctx, page);
+	res = entry->show(hctx, page);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
 }
@@ -129,10 +136,8 @@
 	if (!entry->store)
 		return -EIO;
 
-	res = -ENOENT;
 	mutex_lock(&q->sysfs_lock);
-	if (!blk_queue_dying(q))
-		res = entry->store(hctx, page, length);
+	res = entry->store(hctx, page, length);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
 }
@@ -172,10 +177,6 @@
 	return pos + ret;
 }
 
-static struct attribute *default_ctx_attrs[] = {
-	NULL,
-};
-
 static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
 	.attr = {.name = "nr_tags", .mode = 0444 },
 	.show = blk_mq_hw_sysfs_nr_tags_show,
@@ -195,6 +196,7 @@
 	&blk_mq_hw_sysfs_cpus.attr,
 	NULL,
 };
+ATTRIBUTE_GROUPS(default_hw_ctx);
 
 static const struct sysfs_ops blk_mq_sysfs_ops = {
 	.show	= blk_mq_sysfs_show,
@@ -213,13 +215,12 @@
 
 static struct kobj_type blk_mq_ctx_ktype = {
 	.sysfs_ops	= &blk_mq_sysfs_ops,
-	.default_attrs	= default_ctx_attrs,
-	.release	= blk_mq_sysfs_release,
+	.release	= blk_mq_ctx_sysfs_release,
 };
 
 static struct kobj_type blk_mq_hw_ktype = {
 	.sysfs_ops	= &blk_mq_hw_sysfs_ops,
-	.default_attrs	= default_hw_ctx_attrs,
+	.default_groups = default_hw_ctx_groups,
 	.release	= blk_mq_hw_sysfs_release,
 };
 
@@ -241,21 +242,28 @@
 {
 	struct request_queue *q = hctx->queue;
 	struct blk_mq_ctx *ctx;
-	int i, ret;
+	int i, j, ret;
 
 	if (!hctx->nr_ctx)
 		return 0;
 
-	ret = kobject_add(&hctx->kobj, &q->mq_kobj, "%u", hctx->queue_num);
+	ret = kobject_add(&hctx->kobj, q->mq_kobj, "%u", hctx->queue_num);
 	if (ret)
 		return ret;
 
 	hctx_for_each_ctx(hctx, ctx, i) {
 		ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
 		if (ret)
-			break;
+			goto out;
 	}
 
+	return 0;
+out:
+	hctx_for_each_ctx(hctx, ctx, j) {
+		if (j < i)
+			kobject_del(&ctx->kobj);
+	}
+	kobject_del(&hctx->kobj);
 	return ret;
 }
 
@@ -264,13 +272,13 @@
 	struct blk_mq_hw_ctx *hctx;
 	int i;
 
-	lockdep_assert_held(&q->sysfs_lock);
+	lockdep_assert_held(&q->sysfs_dir_lock);
 
 	queue_for_each_hw_ctx(q, hctx, i)
 		blk_mq_unregister_hctx(hctx);
 
-	kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
-	kobject_del(&q->mq_kobj);
+	kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
+	kobject_del(q->mq_kobj);
 	kobject_put(&dev->kobj);
 
 	q->mq_sysfs_init_done = false;
@@ -290,7 +298,7 @@
 		ctx = per_cpu_ptr(q->queue_ctx, cpu);
 		kobject_put(&ctx->kobj);
 	}
-	kobject_put(&q->mq_kobj);
+	kobject_put(q->mq_kobj);
 }
 
 void blk_mq_sysfs_init(struct request_queue *q)
@@ -298,10 +306,12 @@
 	struct blk_mq_ctx *ctx;
 	int cpu;
 
-	kobject_init(&q->mq_kobj, &blk_mq_ktype);
+	kobject_init(q->mq_kobj, &blk_mq_ktype);
 
 	for_each_possible_cpu(cpu) {
 		ctx = per_cpu_ptr(q->queue_ctx, cpu);
+
+		kobject_get(q->mq_kobj);
 		kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
 	}
 }
@@ -312,13 +322,13 @@
 	int ret, i;
 
 	WARN_ON_ONCE(!q->kobj.parent);
-	lockdep_assert_held(&q->sysfs_lock);
+	lockdep_assert_held(&q->sysfs_dir_lock);
 
-	ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
+	ret = kobject_add(q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
 	if (ret < 0)
 		goto out;
 
-	kobject_uevent(&q->mq_kobj, KOBJ_ADD);
+	kobject_uevent(q->mq_kobj, KOBJ_ADD);
 
 	queue_for_each_hw_ctx(q, hctx, i) {
 		ret = blk_mq_register_hctx(hctx);
@@ -335,30 +345,18 @@
 	while (--i >= 0)
 		blk_mq_unregister_hctx(q->queue_hw_ctx[i]);
 
-	kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
-	kobject_del(&q->mq_kobj);
+	kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
+	kobject_del(q->mq_kobj);
 	kobject_put(&dev->kobj);
 	return ret;
 }
-
-int blk_mq_register_dev(struct device *dev, struct request_queue *q)
-{
-	int ret;
-
-	mutex_lock(&q->sysfs_lock);
-	ret = __blk_mq_register_dev(dev, q);
-	mutex_unlock(&q->sysfs_lock);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(blk_mq_register_dev);
 
 void blk_mq_sysfs_unregister(struct request_queue *q)
 {
 	struct blk_mq_hw_ctx *hctx;
 	int i;
 
-	mutex_lock(&q->sysfs_lock);
+	mutex_lock(&q->sysfs_dir_lock);
 	if (!q->mq_sysfs_init_done)
 		goto unlock;
 
@@ -366,7 +364,7 @@
 		blk_mq_unregister_hctx(hctx);
 
 unlock:
-	mutex_unlock(&q->sysfs_lock);
+	mutex_unlock(&q->sysfs_dir_lock);
 }
 
 int blk_mq_sysfs_register(struct request_queue *q)
@@ -374,7 +372,7 @@
 	struct blk_mq_hw_ctx *hctx;
 	int i, ret = 0;
 
-	mutex_lock(&q->sysfs_lock);
+	mutex_lock(&q->sysfs_dir_lock);
 	if (!q->mq_sysfs_init_done)
 		goto unlock;
 
@@ -385,7 +383,7 @@
 	}
 
 unlock:
-	mutex_unlock(&q->sysfs_lock);
+	mutex_unlock(&q->sysfs_dir_lock);
 
 	return ret;
 }

--
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