mmc: mmc_test: avoid stalled file in debugfs

During card removal and inserting cycle the test file in the debugfs could be
stalled until the host driver removes it. Let's keep the file in the linked
list and destroy it when card is removed.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Per Forlin <per.forlin@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/card/mmc_test.c

@@ -2900,7 +2900,7 @@ static const struct file_operations mmc_test_fops_testlist = {
 	.release	= single_release,
 };
 
-static void mmc_test_free_file_test(struct mmc_card *card)
+static void mmc_test_free_dbgfs_file(struct mmc_card *card)
 {
 	struct mmc_test_dbgfs_file *df, *dfs;
 
@@ -2917,34 +2917,21 @@ static void mmc_test_free_file_test(struct mmc_card *card)
 	mutex_unlock(&mmc_test_lock);
 }
 
-static int mmc_test_register_file_test(struct mmc_card *card)
+static int __mmc_test_register_dbgfs_file(struct mmc_card *card,
+	const char *name, mode_t mode, const struct file_operations *fops)
 {
 	struct dentry *file = NULL;
 	struct mmc_test_dbgfs_file *df;
-	int ret = 0;
-
-	mutex_lock(&mmc_test_lock);
-
-	if (card->debugfs_root)
-		file = debugfs_create_file("test", S_IWUSR | S_IRUGO,
-			card->debugfs_root, card, &mmc_test_fops_test);
-
-	if (IS_ERR_OR_NULL(file)) {
-		dev_err(&card->dev,
-			"Can't create test. Perhaps debugfs is disabled.\n");
-		ret = -ENODEV;
-		goto err;
-	}
 
 	if (card->debugfs_root)
-		file = debugfs_create_file("testlist", S_IRUGO,
-			card->debugfs_root, card, &mmc_test_fops_testlist);
+		file = debugfs_create_file(name, mode, card->debugfs_root,
+			card, fops);
 
 	if (IS_ERR_OR_NULL(file)) {
 		dev_err(&card->dev,
-			"Can't create testlist. Perhaps debugfs is disabled.\n");
-		ret = -ENODEV;
-		goto err;
+			"Can't create %s. Perhaps debugfs is disabled.\n",
+			name);
+		return -ENODEV;
 	}
 
 	df = kmalloc(sizeof(struct mmc_test_dbgfs_file), GFP_KERNEL);
@@ -2952,14 +2939,31 @@ static int mmc_test_register_file_test(struct mmc_card *card)
 		debugfs_remove(file);
 		dev_err(&card->dev,
 			"Can't allocate memory for internal usage.\n");
-		ret = -ENOMEM;
-		goto err;
+		return -ENOMEM;
 	}
 
 	df->card = card;
 	df->file = file;
 
 	list_add(&df->link, &mmc_test_file_test);
+	return 0;
+}
+
+static int mmc_test_register_dbgfs_file(struct mmc_card *card)
+{
+	int ret;
+
+	mutex_lock(&mmc_test_lock);
+
+	ret = __mmc_test_register_dbgfs_file(card, "test", S_IWUSR | S_IRUGO,
+		&mmc_test_fops_test);
+	if (ret)
+		goto err;
+
+	ret = __mmc_test_register_dbgfs_file(card, "testlist", S_IRUGO,
+		&mmc_test_fops_testlist);
+	if (ret)
+		goto err;
 
 err:
 	mutex_unlock(&mmc_test_lock);
@@ -2974,7 +2978,7 @@ static int mmc_test_probe(struct mmc_card *card)
 	if (!mmc_card_mmc(card) && !mmc_card_sd(card))
 		return -ENODEV;
 
-	ret = mmc_test_register_file_test(card);
+	ret = mmc_test_register_dbgfs_file(card);
 	if (ret)
 		return ret;
 
@@ -2986,7 +2990,7 @@ static int mmc_test_probe(struct mmc_card *card)
 static void mmc_test_remove(struct mmc_card *card)
 {
 	mmc_test_free_result(card);
-	mmc_test_free_file_test(card);
+	mmc_test_free_dbgfs_file(card);
 }
 
 static struct mmc_driver mmc_driver = {
@@ -3006,7 +3010,7 @@ static void __exit mmc_test_exit(void)
 {
 	/* Clear stalled data if card is still plugged */
 	mmc_test_free_result(NULL);
-	mmc_test_free_file_test(NULL);
+	mmc_test_free_dbgfs_file(NULL);
 
 	mmc_unregister_driver(&mmc_driver);
 }