sysfs: make sysfs_add/remove_one() call link/unlink_sibling() implictly

When adding or removing a sysfs_dirent, the user used to be required
to call link/unlink separately.  It was for two reasons - code looked
like that before sysfs_addrm_cxt conversion and to avoid looping
through parent_sd->children list twice during removal.

Performance optimization during removal just isn't worth it.  Make
sysfs_add/remove_one() call sysfs_link/unlink_sibing() implicitly.
This makes code simpler albeit slightly less efficient.  This change
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>

5 files changed, 16 insertions, 32 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 9504d4cb63eb..354675ad0965 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -30,7 +30,7 @@ static DEFINE_IDA(sysfs_ino_ida);
  *      Locking:
  *      mutex_lock(sysfs_mutex)
  */
-void sysfs_link_sibling(struct sysfs_dirent *sd)
+static void sysfs_link_sibling(struct sysfs_dirent *sd)
 {
         struct sysfs_dirent *parent_sd = sd->s_parent;
 
@@ -49,7 +49,7 @@ void sysfs_link_sibling(struct sysfs_dirent *sd)
  *      Locking:
  *      mutex_lock(sysfs_mutex)
  */
-void sysfs_unlink_sibling(struct sysfs_dirent *sd)
+static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
 {
         struct sysfs_dirent **pos;
 
@@ -500,6 +500,8 @@ void sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
                 inc_nlink(acxt->parent_inode);
 
         acxt->cnt++;
+
+        sysfs_link_sibling(sd);
 }
 
 /**
@@ -521,7 +523,9 @@ void sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
  */
 void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
 {
-        BUG_ON(sd->s_sibling || (sd->s_flags & SYSFS_FLAG_REMOVED));
+        BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
+
+        sysfs_unlink_sibling(sd);
 
         sd->s_flags |= SYSFS_FLAG_REMOVED;
         sd->s_sibling = acxt->removed;
@@ -697,10 +701,8 @@ static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
         /* link in */
         sysfs_addrm_start(&acxt, parent_sd);
 
-        if (!sysfs_find_dirent(parent_sd, name)) {
+        if (!sysfs_find_dirent(parent_sd, name))
                 sysfs_add_one(&acxt, sd);
-                sysfs_link_sibling(sd);
-        }
 
         if (!sysfs_addrm_finish(&acxt)) {
                 sysfs_put(sd);
@@ -821,7 +823,6 @@ static void remove_dir(struct sysfs_dirent *sd)
         struct sysfs_addrm_cxt acxt;
 
         sysfs_addrm_start(&acxt, sd->s_parent);
-        sysfs_unlink_sibling(sd);
         sysfs_remove_one(&acxt, sd);
         sysfs_addrm_finish(&acxt);
 }
@@ -846,11 +847,9 @@ static void __sysfs_remove_dir(struct sysfs_dirent *dir_sd)
         while (*pos) {
                 struct sysfs_dirent *sd = *pos;
 
-                if (sysfs_type(sd) && sysfs_type(sd) != SYSFS_DIR) {
-                        *pos = sd->s_sibling;
-                        sd->s_sibling = NULL;
+                if (sysfs_type(sd) && sysfs_type(sd) != SYSFS_DIR)
                         sysfs_remove_one(&acxt, sd);
-                } else
+                else
                         pos = &(*pos)->s_sibling;
         }
         sysfs_addrm_finish(&acxt);
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index b21d11b46754..ea0e494d7d58 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -405,10 +405,8 @@ int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
 
         sysfs_addrm_start(&acxt, dir_sd);
 
-        if (!sysfs_find_dirent(dir_sd, attr->name)) {
+        if (!sysfs_find_dirent(dir_sd, attr->name))
                 sysfs_add_one(&acxt, sd);
-                sysfs_link_sibling(sd);
-        }
 
         if (!sysfs_addrm_finish(&acxt)) {
                 sysfs_put(sd);
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 45128b79bc68..efb4062fe099 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -189,25 +189,16 @@ void sysfs_instantiate(struct dentry *dentry, struct inode *inode)
 int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
 {
         struct sysfs_addrm_cxt acxt;
-        struct sysfs_dirent **pos, *sd;
+        struct sysfs_dirent *sd;
 
         if (!dir_sd)
                 return -ENOENT;
 
         sysfs_addrm_start(&acxt, dir_sd);
 
-        for (pos = &dir_sd->s_children; *pos; pos = &(*pos)->s_sibling) {
-                sd = *pos;
-
-                if (!sysfs_type(sd))
-                        continue;
-                if (!strcmp(sd->s_name, name)) {
-                        *pos = sd->s_sibling;
-                        sd->s_sibling = NULL;
-                        sysfs_remove_one(&acxt, sd);
-                        break;
-                }
-        }
+        sd = sysfs_find_dirent(dir_sd, name);
+        if (sd)
+                sysfs_remove_one(&acxt, sd);
 
         if (sysfs_addrm_finish(&acxt))
                 return 0;
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 90484533801e..c129f307936a 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -92,10 +92,8 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
 
         sysfs_addrm_start(&acxt, parent_sd);
 
-        if (!sysfs_find_dirent(parent_sd, name)) {
+        if (!sysfs_find_dirent(parent_sd, name))
                 sysfs_add_one(&acxt, sd);
-                sysfs_link_sibling(sd);
-        }
 
         if (!sysfs_addrm_finish(&acxt)) {
                 error = -EEXIST;
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index b55e510ea239..32b8b64e5cf1 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -56,8 +56,6 @@ extern struct sysfs_dirent sysfs_root;
 extern struct kmem_cache *sysfs_dir_cachep;
 
 extern struct dentry *sysfs_get_dentry(struct sysfs_dirent *sd);
-extern void sysfs_link_sibling(struct sysfs_dirent *sd);
-extern void sysfs_unlink_sibling(struct sysfs_dirent *sd);
 extern struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd);
 extern void sysfs_put_active(struct sysfs_dirent *sd);
 extern struct sysfs_dirent *sysfs_get_active_two(struct sysfs_dirent *sd);