media: siano: Drop unnecessary error check for debugfs_create_dir/file()

Both debugfs_create_dir() and debugfs_create_file() return ERR_PTR
and never return NULL.

As Hans suggested, this patch removes the error checking for both
debugfs_create_dir() and debugfs_create_file() in smsdvb_debugfs_create().
This is because the DebugFS kernel API is developed in a way that the
caller can safely ignore the errors that occur during the creation of
DebugFS nodes. The debugfs APIs have a IS_ERR() judge in start_creating()
which can handle it gracefully. So these checks are unnecessary.

And as Hans pointed out, it's much better to first allocate debug_data
before calling debugfs_create_dir, which need not to clean anything up in
that case.

Fixes: 503efe5 ("[media] siano: split debugfs code into a separate file")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Suggested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

Author: ruanjinjie-eng

drivers/media/common/siano/smsdvb-debugfs.c

@@ -353,31 +353,21 @@ static const struct file_operations debugfs_stats_ops = {
 int smsdvb_debugfs_create(struct smsdvb_client_t *client)
 {
 	struct smscore_device_t *coredev = client->coredev;
-	struct dentry *d;
 	struct smsdvb_debugfs *debug_data;
 
 	if (!smsdvb_debugfs_usb_root || !coredev->is_usb_device)
 		return -ENODEV;
 
-	client->debugfs = debugfs_create_dir(coredev->devpath,
-					     smsdvb_debugfs_usb_root);
-	if (IS_ERR_OR_NULL(client->debugfs)) {
-		pr_info("Unable to create debugfs %s directory.\n",
-			coredev->devpath);
-		return -ENODEV;
-	}
-
-	d = debugfs_create_file("stats", S_IRUGO | S_IWUSR, client->debugfs,
-				client, &debugfs_stats_ops);
-	if (!d) {
-		debugfs_remove(client->debugfs);
-		return -ENOMEM;
-	}
-
 	debug_data = kzalloc(sizeof(*client->debug_data), GFP_KERNEL);
 	if (!debug_data)
 		return -ENOMEM;
 
+	client->debugfs = debugfs_create_dir(coredev->devpath,
+					     smsdvb_debugfs_usb_root);
+
+	debugfs_create_file("stats", S_IRUGO | S_IWUSR, client->debugfs,
+			    client, &debugfs_stats_ops);
+
 	client->debug_data        = debug_data;
 	client->prt_dvb_stats     = smsdvb_print_dvb_stats;
 	client->prt_isdb_stats    = smsdvb_print_isdb_stats;