sysfs, kernfs: introduce kernfs_create_link()

Separate out kernfs symlink interface - kernfs_create_link() - which
takes and returns sysfs_dirents, from sysfs_do_create_link_sd().
sysfs_do_create_link_sd() now just determines the parent and target
sysfs_dirents and invokes the new interface and handles dup warning.

This patch doesn't introduce behavior changes.

v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 46 insertions, 30 deletions

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 71583fc8100a..41138e91947a 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -21,14 +21,48 @@
 
 #include "sysfs.h"
 
+/**
+ * kernfs_create_link - create a symlink
+ * @parent: directory to create the symlink in
+ * @name: name of the symlink
+ * @target: target node for the symlink to point to
+ *
+ * Returns the created node on success, ERR_PTR() value on error.
+ */
+struct sysfs_dirent *kernfs_create_link(struct sysfs_dirent *parent,
+                                        const char *name,
+                                        struct sysfs_dirent *target)
+{
+        struct sysfs_dirent *sd;
+        struct sysfs_addrm_cxt acxt;
+        int error;
+
+        sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);
+        if (!sd)
+                return ERR_PTR(-ENOMEM);
+
+        if (parent->s_flags & SYSFS_FLAG_NS)
+                sd->s_ns = target->s_ns;
+        sd->s_symlink.target_sd = target;
+        sysfs_get(target);      /* ref owned by symlink */
+
+        sysfs_addrm_start(&acxt);
+        error = __sysfs_add_one(&acxt, sd, parent);
+        sysfs_addrm_finish(&acxt);
+
+        if (!error)
+                return sd;
+
+        sysfs_put(sd);
+        return ERR_PTR(error);
+}
+
+
 static int sysfs_do_create_link_sd(struct sysfs_dirent *parent_sd,
                                    struct kobject *target,
                                    const char *name, int warn)
 {
-        struct sysfs_dirent *target_sd = NULL;
-        struct sysfs_dirent *sd = NULL;
-        struct sysfs_addrm_cxt acxt;
-        int error;
+        struct sysfs_dirent *sd, *target_sd = NULL;
 
         BUG_ON(!name || !parent_sd);
 
@@ -42,36 +76,18 @@ static int sysfs_do_create_link_sd(struct sysfs_dirent *parent_sd,
                 target_sd = sysfs_get(target->sd);
         spin_unlock(&sysfs_symlink_target_lock);
 
-        error = -ENOENT;
         if (!target_sd)
-                goto out_put;
+                return -ENOENT;
 
-        error = -ENOMEM;
-        sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);
-        if (!sd)
-                goto out_put;
-
-        if (parent_sd->s_flags & SYSFS_FLAG_NS)
-                sd->s_ns = target_sd->s_ns;
-        sd->s_symlink.target_sd = target_sd;
-        target_sd = NULL;       /* reference is now owned by the symlink */
-
-        sysfs_addrm_start(&acxt);
-        if (warn)
-                error = sysfs_add_one(&acxt, sd, parent_sd);
-        else
-                error = __sysfs_add_one(&acxt, sd, parent_sd);
-        sysfs_addrm_finish(&acxt);
-
-        if (error)
-                goto out_put;
+        sd = kernfs_create_link(parent_sd, name, target_sd);
+        sysfs_put(target_sd);
 
-        return 0;
+        if (!IS_ERR(sd))
+                return 0;
 
- out_put:
-        sysfs_put(target_sd);
-        sysfs_put(sd);
-        return error;
+        if (warn && PTR_ERR(sd) == -EEXIST)
+                sysfs_warn_dup(parent_sd, name);
+        return PTR_ERR(sd);
 }
 
 /**