Re: [PATCH 1/2] init: split get_fs_names

From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>
Cc: viro@zeniv.linux.org.uk, Vivek Goyal <vgoyal@redhat.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	virtio-fs@redhat.com
Subject: Re: [PATCH 1/2] init: split get_fs_names
Date: Mon, 21 Jun 2021 16:09:16 +0100	[thread overview]
Message-ID: <YNCrnCvtlOuZO9jV@casper.infradead.org> (raw)
In-Reply-To: <20210621062657.3641879-2-hch@lst.de>

On Mon, Jun 21, 2021 at 08:26:56AM +0200, Christoph Hellwig wrote:
> -static void __init get_fs_names(char *page)
> +static void __init split_fs_names(char *page, char *names)

If you're going to respin it anyway, can you rename 'page' to 'buf'
or something?  Kind of confusing to have a char * called 'page'.

>  {
> +	strcpy(page, root_fs_names);
> +	while (*page++) {
> +		if (page[-1] == ',')
> +			page[-1] = '\0';
> +	}
> +	*page = '\0';
> +}

is it really worth doing a strcpy() followed by a custom strtok()?
would this work better?

	char c;

	do {
		c =  *root_fs_names++;
		*buf++ = c;
		if (c == ',')
			buf[-1] = '\0';
	} while (c);

> +static void __init get_all_fs_names(char *page)
> +{
> +	int len = get_filesystem_list(page);

it occurs to me that get_filesystem_list() fails silently.  if you build
every linux filesystem in, and want your root on zonefs (assuming
they're alphabetical), we'll fail to find it without a message
indicating that we overflowed the buffer.