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Subject[PATCH 23/75] sysfs: make sysfs_add/remove_one() call link/unlink_sibling() implictly
Date
From: Tejun Heo <htejun@gmail.com>

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>
---
fs/sysfs/dir.c | 21 ++++++++++-----------
fs/sysfs/file.c | 4 +---
fs/sysfs/inode.c | 17 ++++-------------
fs/sysfs/symlink.c | 4 +---
fs/sysfs/sysfs.h | 2 --
5 files changed, 16 insertions(+), 32 deletions(-)
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 9504d4c..354675a 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 b21d11b..ea0e494 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 45128b7..efb4062 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 9048453..c129f30 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 b55e510..32b8b64 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);
--
1.5.3.4
-
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