linux-kernel - [PATCH] bcache: reduce redundant code in bch_cached_dev

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Date:   Sat, 6 Mar 2021 10:43:59 +0800
From:   Zhiqiang Liu <liuzhiqiang26@...wei.com>
To:     <colyli@...e.de>, <linux-bcache@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     linfeilong <linfeilong@...wei.com>, <liuzhiqiang26@...wei.com>,
        lixiaokeng <lixiaokeng@...wei.com>,
        lihaotian <lihaotian9@...wei.com>, <kent.overstreet@...il.com>
Subject: [PATCH] bcache: reduce redundant code in bch_cached_dev_run()


In bch_cached_dev_run(), free(env[1])|free(env[2])|free(buf)
show up three times. This patch introduce out tag in
which free(env[1])|free(env[2])|free(buf) are only called
one time. If we need to call free() when errors occur,
we can set error code to ret, and then goto out tag directly.

Signed-off-by: Zhiqiang Liu <liuzhiqiang26@...wei.com>
---
 drivers/md/bcache/super.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 71691f32959b..1a8748050087 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -1052,6 +1052,7 @@ static int cached_dev_status_update(void *arg)

 int bch_cached_dev_run(struct cached_dev *dc)
 {
+	int ret = 0;
 	struct bcache_device *d = &dc->disk;
 	char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
 	char *env[] = {
@@ -1064,19 +1065,15 @@ int bch_cached_dev_run(struct cached_dev *dc)
 	if (dc->io_disable) {
 		pr_err("I/O disabled on cached dev %s\n",
 		       dc->backing_dev_name);
-		kfree(env[1]);
-		kfree(env[2]);
-		kfree(buf);
-		return -EIO;
+		ret = -EIO;
+		goto out;
 	}

 	if (atomic_xchg(&dc->running, 1)) {
-		kfree(env[1]);
-		kfree(env[2]);
-		kfree(buf);
 		pr_info("cached dev %s is running already\n",
 		       dc->backing_dev_name);
-		return -EBUSY;
+		ret = -EBUSY;
+		goto out;
 	}

 	if (!d->c &&
@@ -1097,15 +1094,13 @@ int bch_cached_dev_run(struct cached_dev *dc)
 	 * only class / kset properties are persistent
 	 */
 	kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
-	kfree(env[1]);
-	kfree(env[2]);
-	kfree(buf);

 	if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
 	    sysfs_create_link(&disk_to_dev(d->disk)->kobj,
 			      &d->kobj, "bcache")) {
 		pr_err("Couldn't create bcache dev <-> disk sysfs symlinks\n");
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto out;
 	}

 	dc->status_update_thread = kthread_run(cached_dev_status_update,
@@ -1114,7 +1109,11 @@ int bch_cached_dev_run(struct cached_dev *dc)
 		pr_warn("failed to create bcache_status_update kthread, continue to run without monitoring backing device status\n");
 	}

-	return 0;
+out:
+	kfree(env[1]);
+	kfree(env[2]);
+	kfree(buf);
+	return ret;
 }

 /*
-- 
2.19.1