sysfs, kernfs: replace sysfs_dirent->s_dir.kobj and ->s_attr.[bin_]attr with ->priv

A directory sysfs_dirent points to the associated kobj.  A regular or
bin file points to the associated [bin_]attribute.  This patch
replaces sysfs_dirent->s_dir.kobj and ->s_attr.[bin_]attr with void *
->priv.

This is to prepare for kernfs interface so that sysfs can specify the
private data in the same way for directories and files.  This lower
debuggability but not by much - the whole thing was overlaid in a
union anyway.  If debuggability becomes an issue, we can later add
->priv accessors which explicitly check for the sysfs_dirent type and
performs casting.

This patch doesn't introduce any behavior difference.

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

5 files changed, 21 insertions, 24 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 5ba896630d04..aeb08bd3f3dd 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -681,7 +681,7 @@ static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
                 return -ENOMEM;
 
         sd->s_ns = ns;
-        sd->s_dir.kobj = kobj;
+        sd->priv = kobj;
 
         /* link in */
         sysfs_addrm_start(&acxt);
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 0f3f0a252a50..9b58d874c825 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -74,7 +74,7 @@ static struct sysfs_open_file *sysfs_of(struct file *file)
  */
 static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd)
 {
-        struct kobject *kobj = sd->s_parent->s_dir.kobj;
+        struct kobject *kobj = sd->s_parent->priv;
 
         if (!sysfs_ignore_lockdep(sd))
                 lockdep_assert_held(sd);
@@ -89,7 +89,7 @@ static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd)
 static int sysfs_seq_show(struct seq_file *sf, void *v)
 {
         struct sysfs_open_file *of = sf->private;
-        struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
+        struct kobject *kobj = of->sd->s_parent->priv;
         const struct sysfs_ops *ops;
         char *buf;
         ssize_t count;
@@ -120,7 +120,7 @@ static int sysfs_seq_show(struct seq_file *sf, void *v)
          */
         ops = sysfs_file_ops(of->sd);
         if (ops->show)
-                count = ops->show(kobj, of->sd->s_attr.attr, buf);
+                count = ops->show(kobj, of->sd->priv, buf);
         else
                 count = 0;
 
@@ -154,8 +154,8 @@ static ssize_t sysfs_bin_read(struct file *file, char __user *userbuf,
                               size_t bytes, loff_t *off)
 {
         struct sysfs_open_file *of = sysfs_of(file);
-        struct bin_attribute *battr = of->sd->s_attr.bin_attr;
-        struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
+        struct bin_attribute *battr = of->sd->priv;
+        struct kobject *kobj = of->sd->s_parent->priv;
         loff_t size = file_inode(file)->i_size;
         int count = min_t(size_t, bytes, PAGE_SIZE);
         loff_t offs = *off;
@@ -221,7 +221,7 @@ static ssize_t sysfs_bin_read(struct file *file, char __user *userbuf,
 static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off,
                               size_t count)
 {
-        struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
+        struct kobject *kobj = of->sd->s_parent->priv;
         int rc = 0;
 
         /*
@@ -236,7 +236,7 @@ static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off,
         }
 
         if (sysfs_is_bin(of->sd)) {
-                struct bin_attribute *battr = of->sd->s_attr.bin_attr;
+                struct bin_attribute *battr = of->sd->priv;
 
                 rc = -EIO;
                 if (battr->write)
@@ -245,7 +245,7 @@ static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off,
         } else {
                 const struct sysfs_ops *ops = sysfs_file_ops(of->sd);
 
-                rc = ops->store(kobj, of->sd->s_attr.attr, buf, count);
+                rc = ops->store(kobj, of->sd->priv, buf, count);
         }
 
         sysfs_put_active(of->sd);
@@ -466,8 +466,8 @@ static const struct vm_operations_struct sysfs_bin_vm_ops = {
 static int sysfs_bin_mmap(struct file *file, struct vm_area_struct *vma)
 {
         struct sysfs_open_file *of = sysfs_of(file);
-        struct bin_attribute *battr = of->sd->s_attr.bin_attr;
-        struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
+        struct bin_attribute *battr = of->sd->priv;
+        struct kobject *kobj = of->sd->s_parent->priv;
         int rc;
 
         mutex_lock(&of->mutex);
@@ -607,7 +607,7 @@ static void sysfs_put_open_dirent(struct sysfs_dirent *sd,
 static int sysfs_open_file(struct inode *inode, struct file *file)
 {
         struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
-        struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
+        struct kobject *kobj = attr_sd->s_parent->priv;
         struct sysfs_open_file *of;
         bool has_read, has_write, has_mmap;
         int error = -EACCES;
@@ -617,7 +617,7 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
                 return -ENODEV;
 
         if (sysfs_is_bin(attr_sd)) {
-                struct bin_attribute *battr = attr_sd->s_attr.bin_attr;
+                struct bin_attribute *battr = attr_sd->priv;
 
                 has_read = battr->read || battr->mmap;
                 has_write = battr->write || battr->mmap;
@@ -848,7 +848,7 @@ int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
                 return -ENOMEM;
 
         sd->s_ns = ns;
-        sd->s_attr.attr = (void *)attr;
+        sd->priv = (void *)attr;
         sysfs_dirent_init_lockdep(sd);
 
         sysfs_addrm_start(&acxt);
diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 5f7e2afb3457..81cc8585b32c 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -275,7 +275,7 @@ static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
                 inode->i_fop = &sysfs_file_operations;
                 break;
         case SYSFS_KOBJ_BIN_ATTR:
-                bin_attr = sd->s_attr.bin_attr;
+                bin_attr = sd->priv;
                 inode->i_size = bin_attr->size;
                 inode->i_fop = &sysfs_bin_operations;
                 break;
diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 0922c53bd757..352fbbbc0551 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -223,7 +223,7 @@ int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *targ,
         result = -EINVAL;
         if (sysfs_type(sd) != SYSFS_KOBJ_LINK)
                 goto out;
-        if (sd->s_symlink.target_sd->s_dir.kobj != targ)
+        if (sd->s_symlink.target_sd->priv != targ)
                 goto out;
 
         result = kernfs_rename_ns(sd, parent_sd, new, new_ns);
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 2abccfdd932e..a6f3fa3f02fe 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -17,8 +17,6 @@ struct sysfs_open_dirent;
 
 /* type-specific structures for sysfs_dirent->s_* union members */
 struct sysfs_elem_dir {
-        struct kobject          *kobj;
-
         unsigned long           subdirs;
         /* children rbtree starts here and goes through sd->s_rb */
         struct rb_root          children;
@@ -29,10 +27,6 @@ struct sysfs_elem_symlink {
 };
 
 struct sysfs_elem_attr {
-        union {
-                struct attribute        *attr;
-                struct bin_attribute    *bin_attr;
-        };
         struct sysfs_open_dirent *open;
 };
 
@@ -74,6 +68,8 @@ struct sysfs_dirent {
                 struct sysfs_elem_attr          s_attr;
         };
 
+        void                    *priv;
+
         unsigned short          s_flags;
         umode_t                 s_mode;
         unsigned int            s_ino;
@@ -103,7 +99,7 @@ static inline unsigned int sysfs_type(struct sysfs_dirent *sd)
 
 #define sysfs_dirent_init_lockdep(sd)                           \
 do {                                                            \
-        struct attribute *attr = sd->s_attr.attr;               \
+        struct attribute *attr = sd->priv;                      \
         struct lock_class_key *key = attr->key;                 \
         if (!key)                                               \
                 key = &attr->skey;                              \
@@ -114,10 +110,11 @@ do {								\
 /* Test for attributes that want to ignore lockdep for read-locking */
 static inline bool sysfs_ignore_lockdep(struct sysfs_dirent *sd)
 {
+        struct attribute *attr = sd->priv;
         int type = sysfs_type(sd);
 
         return (type == SYSFS_KOBJ_ATTR || type == SYSFS_KOBJ_BIN_ATTR) &&
-                sd->s_attr.attr->ignore_lockdep;
+                attr->ignore_lockdep;
 }
 
 #else