sysfs: make sysfs_add_one() automatically check for duplicate entry

Make sysfs_add_one() check for duplicate entry and return -EEXIST if
such entry exists.  This simplifies node addition code a bit.

This patch doesn't introduce any noticeable behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 17 insertions, 9 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 354675ad0965..620603296c6c 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -491,9 +491,16 @@ void sysfs_addrm_start(struct sysfs_addrm_cxt *acxt,
  *
  *      LOCKING:
  *      Determined by sysfs_addrm_start().
+ *
+ *      RETURNS:
+ *      0 on success, -EEXIST if entry with the given name already
+ *      exists.
  */
-void sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
+int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
 {
+        if (sysfs_find_dirent(acxt->parent_sd, sd->s_name))
+                return -EEXIST;
+
         sd->s_parent = sysfs_get(acxt->parent_sd);
 
         if (sysfs_type(sd) == SYSFS_DIR && acxt->parent_inode)
@@ -502,6 +509,8 @@ void sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
         acxt->cnt++;
 
         sysfs_link_sibling(sd);
+
+        return 0;
 }
 
 /**
@@ -691,6 +700,7 @@ static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
         umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
         struct sysfs_addrm_cxt acxt;
         struct sysfs_dirent *sd;
+        int rc;
 
         /* allocate */
         sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
@@ -700,17 +710,15 @@ static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
 
         /* link in */
         sysfs_addrm_start(&acxt, parent_sd);
+        rc = sysfs_add_one(&acxt, sd);
+        sysfs_addrm_finish(&acxt);
 
-        if (!sysfs_find_dirent(parent_sd, name))
-                sysfs_add_one(&acxt, sd);
-
-        if (!sysfs_addrm_finish(&acxt)) {
+        if (rc == 0)
+                *p_sd = sd;
+        else
                 sysfs_put(sd);
-                return -EEXIST;
-        }
 
-        *p_sd = sd;
-        return 0;
+        return rc;
 }
 
 int sysfs_create_subdir(struct kobject *kobj, const char *name,