Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760627AbYAYHYi (ORCPT ); Fri, 25 Jan 2008 02:24:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758676AbYAYHPz (ORCPT ); Fri, 25 Jan 2008 02:15:55 -0500 Received: from ns1.suse.de ([195.135.220.2]:52569 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758656AbYAYHPx (ORCPT ); Fri, 25 Jan 2008 02:15:53 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Kay Sievers , Denis Cheng , Greg Kroah-Hartman Subject: [PATCH 031/196] sysfs: create optimal relative symlink targets Date: Thu, 24 Jan 2008 23:09:29 -0800 Message-Id: <1201245134-4876-31-git-send-email-gregkh@suse.de> X-Mailer: git-send-email 1.5.3.8 In-Reply-To: <20080125071127.GA4860@kroah.com> References: <20080125071127.GA4860@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3887 Lines: 151 From: Kay Sievers Instead of walking from the source down to the root of sysfs, and back to the target, we stop at the first directory the source and the target share. This link: /devices/pci0000:00/0000:00:1d.7/usb1/1-0:1.0/ep_81 pointed to: ../../../../../devices/pci0000:00/0000:00:1d.0/usb2/2-0:1.0/usb_endpoint/usbdev2.1_ep81 now it just points to: usb_endpoint/usbdev1.1_ep81 Thanks to Denis Cheng for bringing this up, and sending the initial patch. CC: Denis Cheng Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/symlink.c | 88 +++++++++++++++++++++++++--------------------------- 1 files changed, 42 insertions(+), 46 deletions(-) diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c index 3eac20c..5f66c44 100644 --- a/fs/sysfs/symlink.c +++ b/fs/sysfs/symlink.c @@ -19,39 +19,6 @@ #include "sysfs.h" -static int object_depth(struct sysfs_dirent *sd) -{ - int depth = 0; - - for (; sd->s_parent; sd = sd->s_parent) - depth++; - - return depth; -} - -static int object_path_length(struct sysfs_dirent * sd) -{ - int length = 1; - - for (; sd->s_parent; sd = sd->s_parent) - length += strlen(sd->s_name) + 1; - - return length; -} - -static void fill_object_path(struct sysfs_dirent *sd, char *buffer, int length) -{ - --length; - for (; sd->s_parent; sd = sd->s_parent) { - int cur = strlen(sd->s_name); - - /* back up enough to print this bus id with '/' */ - length -= cur; - strncpy(buffer + length, sd->s_name, cur); - *(buffer + --length) = '/'; - } -} - /** * sysfs_create_link - create symlink between two objects. * @kobj: object whose directory we're creating the link in. @@ -112,7 +79,6 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char return error; } - /** * sysfs_remove_link - remove symlink in object's directory. * @kobj: object we're acting for. @@ -124,24 +90,54 @@ void sysfs_remove_link(struct kobject * kobj, const char * name) sysfs_hash_and_remove(kobj->sd, name); } -static int sysfs_get_target_path(struct sysfs_dirent * parent_sd, - struct sysfs_dirent * target_sd, char *path) +static int sysfs_get_target_path(struct sysfs_dirent *parent_sd, + struct sysfs_dirent *target_sd, char *path) { - char * s; - int depth, size; + struct sysfs_dirent *base, *sd; + char *s = path; + int len = 0; + + /* go up to the root, stop at the base */ + base = parent_sd; + while (base->s_parent) { + sd = target_sd->s_parent; + while (sd->s_parent && base != sd) + sd = sd->s_parent; + + if (base == sd) + break; + + strcpy(s, "../"); + s += 3; + base = base->s_parent; + } + + /* determine end of target string for reverse fillup */ + sd = target_sd; + while (sd->s_parent && sd != base) { + len += strlen(sd->s_name) + 1; + sd = sd->s_parent; + } - depth = object_depth(parent_sd); - size = object_path_length(target_sd) + depth * 3 - 1; - if (size > PATH_MAX) + /* check limits */ + if (len < 2) + return -EINVAL; + len--; + if ((s - path) + len > PATH_MAX) return -ENAMETOOLONG; - pr_debug("%s: depth = %d, size = %d\n", __FUNCTION__, depth, size); + /* reverse fillup of target string from target to base */ + sd = target_sd; + while (sd->s_parent && sd != base) { + int slen = strlen(sd->s_name); - for (s = path; depth--; s += 3) - strcpy(s,"../"); + len -= slen; + strncpy(s + len, sd->s_name, slen); + if (len) + s[--len] = '/'; - fill_object_path(target_sd, path, size); - pr_debug("%s: path = '%s'\n", __FUNCTION__, path); + sd = sd->s_parent; + } return 0; } -- 1.5.3.8 -- 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/