linux-kernel - Re: [PATCH 3/9] VFS: Introduce a mount context

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Message-ID: <1493835998.22125.15.camel@perches.com>
Date:   Wed, 03 May 2017 11:26:38 -0700
From:   Joe Perches <joe@...ches.com>
To:     Jeff Layton <jlayton@...chiereds.net>,
        David Howells <dhowells@...hat.com>, viro@...iv.linux.org.uk
Cc:     linux-fsdevel@...r.kernel.org, linux-nfs@...r.kernel.org,
        linux-kernel@...r.kernel.org, mszeredi@...hat.com
Subject: Re: [PATCH 3/9] VFS: Introduce a mount context

On Wed, 2017-05-03 at 14:13 -0400, Jeff Layton wrote:
> On Wed, 2017-05-03 at 17:04 +0100, David Howells wrote:
> > Introduce a mount context concept.

trivia:

> > static int selinux_mount_ctx_option(struct mount_context *mc, char *opt)
> > +{
[]
> > +	if (opts->mnt_opts) {
> > +		oo = kmalloc((opts->num_mnt_opts + 1) * sizeof(char *),
> > +			     GFP_KERNEL);
> > +		if (!oo)
> > +			return -ENOMEM;
> > +		memcpy(oo, opts->mnt_opts, opts->num_mnt_opts * sizeof(char *));
> > +		oo[opts->num_mnt_opts] = NULL;
> > +		old = opts->mnt_opts;
> > +		opts->mnt_opts = oo;
> > +		kfree(old);
> > +	}

krealloc would probably be more efficient and possible
readable as likely there's already padding in the original
allocation.

Are there no locking constraints?