Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-omap-h63xx.git] / fs / sysfs / symlink.c

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 3eac20c63c419d45cc666a53251be208ebf1296a..a3ba217fbe74f4313a1dca88a8cc863e14766341 100644 (file)
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -19,46 +19,8 @@
 
 #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.
- *     @target:        object we're pointing to.
- *     @name:          name of the symlink.
- */
-int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char * name)
+static int sysfs_do_create_link(struct kobject *kobj, struct kobject *target,
+                               const char *name, int warn)
 {
        struct sysfs_dirent *parent_sd = NULL;
        struct sysfs_dirent *target_sd = NULL;
@@ -98,7 +60,10 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
        target_sd = NULL;       /* reference is now owned by the symlink */
 
        sysfs_addrm_start(&acxt, parent_sd);
-       error = sysfs_add_one(&acxt, sd);
+       if (warn)
+               error = sysfs_add_one(&acxt, sd);
+       else
+               error = __sysfs_add_one(&acxt, sd);
        sysfs_addrm_finish(&acxt);
 
        if (error)
@@ -112,6 +77,32 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
        return error;
 }
 
+/**
+ *     sysfs_create_link - create symlink between two objects.
+ *     @kobj:  object whose directory we're creating the link in.
+ *     @target:        object we're pointing to.
+ *     @name:          name of the symlink.
+ */
+int sysfs_create_link(struct kobject *kobj, struct kobject *target,
+                     const char *name)
+{
+       return sysfs_do_create_link(kobj, target, name, 1);
+}
+
+/**
+ *     sysfs_create_link_nowarn - create symlink between two objects.
+ *     @kobj:  object whose directory we're creating the link in.
+ *     @target:        object we're pointing to.
+ *     @name:          name of the symlink.
+ *
+ *     This function does the same as sysf_create_link(), but it
+ *     doesn't warn if the link already exists.
+ */
+int sysfs_create_link_nowarn(struct kobject *kobj, struct kobject *target,
+                            const char *name)
+{
+       return sysfs_do_create_link(kobj, target, name, 0);
+}
 
 /**
  *     sysfs_remove_link - remove symlink in object's directory.
@@ -121,27 +112,64 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
 
 void sysfs_remove_link(struct kobject * kobj, const char * name)
 {
-       sysfs_hash_and_remove(kobj->sd, name);
+       struct sysfs_dirent *parent_sd = NULL;
+
+       if (!kobj)
+               parent_sd = &sysfs_root;
+       else
+               parent_sd = kobj->sd;
+
+       sysfs_hash_and_remove(parent_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;
+       }
 
-       depth = object_depth(parent_sd);
-       size = object_path_length(target_sd) + depth * 3 - 1;
-       if (size > PATH_MAX)
+       /* 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;
+       }
+
+       /* 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;
 }