From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Eric W. Biederman" Subject: [PATCH 08/24] sysfs: Optimize just changing the sysfs file mode. Date: Thu, 28 May 2009 16:00:49 -0700 Message-ID: <1243551665-23596-8-git-send-email-ebiederm@xmission.com> References: Cc: , Tejun Heo , Cornelia Huck , , Kay Sievers , Greg KH , "Eric W. Biederman" , "Eric W. Biederman" To: Andrew Morton , Greg Kroah-Hartman Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]:48841 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752819AbZE1XCW (ORCPT ); Thu, 28 May 2009 19:02:22 -0400 In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: From: Eric W. Biederman Don't allocate a struct iattr for the sysfs dentry if just the mode changes because we have a field for that on the sysfs_dirent, and we can trigger that case with sysfs_chmod_file. Signed-off-by: Eric W. Biederman --- fs/sysfs/inode.c | 22 ++++++++++++++-------- 1 files changed, 14 insertions(+), 8 deletions(-) diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index 555f0ff..70ff2a2 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -60,12 +60,16 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) return error; iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */ + if (iattr->ia_valid & ATTR_MODE) { + if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) + iattr->ia_mode &= ~S_ISGID; + } error = inode_setattr(inode, iattr); if (error) return error; - if (!sd_iattr) { + if (!sd_iattr && (ia_valid & ~ATTR_MODE)) { /* setting attributes for the first time, allocate now */ sd_iattr = kzalloc(sizeof(struct iattr), GFP_KERNEL); if (!sd_iattr) @@ -78,6 +82,13 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) sd->s_iattr = sd_iattr; } + if (ia_valid & ATTR_MODE) + sd->s_mode = iattr->ia_mode; + + /* If we don't need the extra attributes leave */ + if (!sd_iattr) + return 0; + /* attributes were changed atleast once in past */ if (ia_valid & ATTR_UID) @@ -93,13 +104,8 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr) if (ia_valid & ATTR_CTIME) sd_iattr->ia_ctime = timespec_trunc(iattr->ia_ctime, inode->i_sb->s_time_gran); - if (ia_valid & ATTR_MODE) { - umode_t mode = iattr->ia_mode; - - if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) - mode &= ~S_ISGID; - sd_iattr->ia_mode = sd->s_mode = mode; - } + if (ia_valid & ATTR_MODE) + sd_iattr->ia_mode = iattr->ia_mode; return error; } -- 1.6.3.1.54.g99dd.dirty