Access files from kernel

From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>,
	Ming Lei <ming.lei@canonical.com>,
	Greg KH <gregkh@linuxfoundation.org>, Kay Sievers <kay@vrfy.org>,
	Lennart Poettering <lennart@poettering.net>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Kay Sievers <kay@redhat.com>,
	Linux Media Mailing List <linux-media@vger.kernel.org>,
	Michael Krufky <mkrufky@linuxtv.org>,
	Ivan Kalvachev <ikalvachev@gmail.com>
Subject: Access files from kernel
Date: Wed, 3 Oct 2012 22:48:39 +0300	[thread overview]
Message-ID: <20121003194819.GA2490@shutemov.name> (raw)
In-Reply-To: <CA+55aFweE2BgGjGkxLPkmHeV=Omc4RsuU6Kc6SLZHgJPsqDpeA@mail.gmail.com>

On Wed, Oct 03, 2012 at 09:38:52AM -0700, Linus Torvalds wrote:
>+static bool fw_get_filesystem_firmware(struct firmware *fw, const char *name)
>+{
>+	int i;
>+	bool success = false;
>+	const char *fw_path[] = { "/lib/firmware/update", "/firmware", "/lib/firmware" };
>+	char *path = __getname();
>+
>+printk("Trying to load fw '%s' ", name);
>+	for (i = 0; i < ARRAY_SIZE(fw_path); i++) {
>+		struct file *file;
>+		snprintf(path, PATH_MAX, "%s/%s", fw_path[i], name);
>+
>+		file = filp_open(path, O_RDONLY, 0);

AFAIK, accessing files on filesystem form kernel directly was no-go for a
long time. What's the new rule here?

Is it worth to introduce an execption, if it's possible to solve the
problem in userspace.

-- 
 Kirill A. Shutemov