Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752784AbZJKWjo (ORCPT ); Sun, 11 Oct 2009 18:39:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751882AbZJKWjn (ORCPT ); Sun, 11 Oct 2009 18:39:43 -0400 Received: from mail-ew0-f208.google.com ([209.85.219.208]:48865 "EHLO mail-ew0-f208.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752468AbZJKWjm (ORCPT ); Sun, 11 Oct 2009 18:39:42 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; b=mPC2HxAxEI8hkM4FFM/JFtwfnzr3xSh6AaTiXwQoOZfbsvqW9JIXwt3jDcbxCJklyG WAuyQ53EPyi3ZP/5Zs5qPYcwXfotPLsJNwWBnHyqQXtXnGw/bSSYONAqkLvPqe0N8M8c hDngYFsIVHFb0GgBE9li42w07F374tGwTszE4= From: Frederic Weisbecker To: Thomas Gleixner Cc: LKML , Frederic Weisbecker , Thomas Gleixner , Ingo Molnar , John Kacur , Sven-Thorsten Dietrich , Jonathan Corbet , Alessio Igor Bogani , Arnd Bergmann , Alan Cox Subject: [PATCH v2] generic_nvram: Turn nvram_ioctl into an unlocked ioctl Date: Mon, 12 Oct 2009 00:39:02 +0200 Message-Id: <1255300742-8863-1-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.6.2.3 In-Reply-To: <200910120025.05208.arnd@arndb.de> References: <200910120025.05208.arnd@arndb.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2414 Lines: 69 nvram_ioctl is a bkl locked ioctl, but it can be an unlocked ioctl. - part is provided by the user - offset is provided by pmac_get_partition() which is safe as it only touches nvram_partitions, an array inistialized on __init time and read-only the rest of the time. - nvram_sync() only relies on core99_nvram_sync() which checks is_core_99, nvram_data, nvram_image. Those are variables initialized on __init time only and their direct values are not touched further. The rest modifies the nvram image header, protected by nv_lock already. So it's safe to call nvram_ioctl without the big kernel lock held. v2: Fix nvram_ioctl to fit unlocked_ioctl signature. Reported-by: Arnd Bergmann Signed-off-by: Frederic Weisbecker Cc: Thomas Gleixner Cc: Ingo Molnar Cc: John Kacur Cc: Sven-Thorsten Dietrich Cc: Jonathan Corbet Cc: Alessio Igor Bogani Cc: Arnd Bergmann Cc: Alan Cox --- drivers/char/generic_nvram.c | 13 ++++++------- 1 files changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/char/generic_nvram.c b/drivers/char/generic_nvram.c index c49200e..866d04d 100644 --- a/drivers/char/generic_nvram.c +++ b/drivers/char/generic_nvram.c @@ -85,8 +85,7 @@ static ssize_t write_nvram(struct file *file, const char __user *buf, return p - buf; } -static int nvram_ioctl(struct inode *inode, struct file *file, - unsigned int cmd, unsigned long arg) +static int nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { switch(cmd) { #ifdef CONFIG_PPC_PMAC @@ -118,11 +117,11 @@ static int nvram_ioctl(struct inode *inode, struct file *file, } const struct file_operations nvram_fops = { - .owner = THIS_MODULE, - .llseek = nvram_llseek, - .read = read_nvram, - .write = write_nvram, - .ioctl = nvram_ioctl, + .owner = THIS_MODULE, + .llseek = nvram_llseek, + .read = read_nvram, + .write = write_nvram, + .unlocked_ioctl = nvram_ioctl, }; static struct miscdevice nvram_dev = { -- 1.6.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/