[PATCH] inode_diet: Replace inode.u.generic_ip with inode.i_private

The following patches reduce the size of the VFS inode structure by 28 bytes
on a UP x86.  (It would be more on an x86_64 system).  This is a 10% reduction
in the inode size on a UP kernel that is configured in a production mode
(i.e., with no spinlock or other debugging functions enabled; if you want to
save memory taken up by in-core inodes, the first thing you should do is
disable the debugging options; they are responsible for a huge amount of bloat
in the VFS inode structure).

This patch:

The filesystem or device-specific pointer in the inode is inside a union,
which is pretty pointless given that all 30+ users of this field have been
using the void pointer.  Get rid of the union and rename it to i_private, with
a comment to explain who is allowed to use the void pointer.  This is just a
cleanup, but it allows us to reuse the union 'u' for something something where
the union will actually be used.

[judith@osdl.org: powerpc build fix]
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Judith Lebzelter <judith@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

13 files changed, 38 insertions, 38 deletions

diff --git a/fs/autofs/inode.c b/fs/autofs/inode.c
index c81d6b8c2828..d39d2acd9b38 100644
--- a/fs/autofs/inode.c
+++ b/fs/autofs/inode.c
@@ -241,7 +241,7 @@ static void autofs_read_inode(struct inode *inode)
                 
                 inode->i_op = &autofs_symlink_inode_operations;
                 sl = &sbi->symlink[n];
-                inode->u.generic_ip = sl;
+                inode->i_private = sl;
                 inode->i_mode = S_IFLNK | S_IRWXUGO;
                 inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = sl->mtime;
                 inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
diff --git a/fs/autofs/symlink.c b/fs/autofs/symlink.c
index 52e8772b066e..c74f2eb65775 100644
--- a/fs/autofs/symlink.c
+++ b/fs/autofs/symlink.c
@@ -15,7 +15,7 @@
 /* Nothing to release.. */
 static void *autofs_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
-        char *s=((struct autofs_symlink *)dentry->d_inode->u.generic_ip)->data;
+        char *s=((struct autofs_symlink *)dentry->d_inode->i_private)->data;
         nd_set_link(nd, s);
         return NULL;
 }
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 34ebbc191e46..6759b9839ce8 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -517,7 +517,7 @@ static struct inode *bm_get_inode(struct super_block *sb, int mode)
 
 static void bm_clear_inode(struct inode *inode)
 {
-        kfree(inode->u.generic_ip);
+        kfree(inode->i_private);
 }
 
 static void kill_node(Node *e)
@@ -545,7 +545,7 @@ static void kill_node(Node *e)
 static ssize_t
 bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
 {
-        Node *e = file->f_dentry->d_inode->u.generic_ip;
+        Node *e = file->f_dentry->d_inode->i_private;
         loff_t pos = *ppos;
         ssize_t res;
         char *page;
@@ -579,7 +579,7 @@ static ssize_t bm_entry_write(struct file *file, const char __user *buffer,
                                 size_t count, loff_t *ppos)
 {
         struct dentry *root;
-        Node *e = file->f_dentry->d_inode->u.generic_ip;
+        Node *e = file->f_dentry->d_inode->i_private;
         int res = parse_command(buffer, count);
 
         switch (res) {
@@ -646,7 +646,7 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
         }
 
         e->dentry = dget(dentry);
-        inode->u.generic_ip = e;
+        inode->i_private = e;
         inode->i_fop = &bm_entry_operations;
 
         d_instantiate(dentry, inode);
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index e4b430552c88..bf3901ab1744 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -32,8 +32,8 @@ static ssize_t default_write_file(struct file *file, const char __user *buf,
 
 static int default_open(struct inode *inode, struct file *file)
 {
-        if (inode->u.generic_ip)
-                file->private_data = inode->u.generic_ip;
+        if (inode->i_private)
+                file->private_data = inode->i_private;
 
         return 0;
 }
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 3ca268d2e5a2..717f4821ed02 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -168,7 +168,7 @@ static int debugfs_create_by_name(const char *name, mode_t mode,
  *          directory dentry if set.  If this paramater is NULL, then the
  *          file will be created in the root of the debugfs filesystem.
  * @data: a pointer to something that the caller will want to get to later
- *        on.  The inode.u.generic_ip pointer will point to this value on
+ *        on.  The inode.i_private pointer will point to this value on
  *        the open() call.
  * @fops: a pointer to a struct file_operations that should be used for
  *        this file.
@@ -209,7 +209,7 @@ struct dentry *debugfs_create_file(const char *name, mode_t mode,
 
         if (dentry->d_inode) {
                 if (data)
-                        dentry->d_inode->u.generic_ip = data;
+                        dentry->d_inode->i_private = data;
                 if (fops)
                         dentry->d_inode->i_fop = fops;
         }
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index f7aef5bb584a..5bf06a10dddf 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -177,7 +177,7 @@ int devpts_pty_new(struct tty_struct *tty)
         inode->i_gid = config.setgid ? config.gid : current->fsgid;
         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
         init_special_inode(inode, S_IFCHR|config.mode, device);
-        inode->u.generic_ip = tty;
+        inode->i_private = tty;
 
         dentry = get_node(number);
         if (!IS_ERR(dentry) && !dentry->d_inode)
@@ -196,7 +196,7 @@ struct tty_struct *devpts_get_tty(int number)
         tty = NULL;
         if (!IS_ERR(dentry)) {
                 if (dentry->d_inode)
-                        tty = dentry->d_inode->u.generic_ip;
+                        tty = dentry->d_inode->i_private;
                 dput(dentry);
         }
 
diff --git a/fs/freevxfs/vxfs.h b/fs/freevxfs/vxfs.h
index d35979a58743..c8a92652612a 100644
--- a/fs/freevxfs/vxfs.h
+++ b/fs/freevxfs/vxfs.h
@@ -252,7 +252,7 @@ enum {
  * Get filesystem private data from VFS inode.
  */
 #define VXFS_INO(ip) \
-        ((struct vxfs_inode_info *)(ip)->u.generic_ip)
+        ((struct vxfs_inode_info *)(ip)->i_private)
 
 /*
  * Get filesystem private data from VFS superblock.
diff --git a/fs/freevxfs/vxfs_inode.c b/fs/freevxfs/vxfs_inode.c
index ca6a39714771..32a82ed108e4 100644
--- a/fs/freevxfs/vxfs_inode.c
+++ b/fs/freevxfs/vxfs_inode.c
@@ -243,7 +243,7 @@ vxfs_iinit(struct inode *ip, struct vxfs_inode_info *vip)
         ip->i_blocks = vip->vii_blocks;
         ip->i_generation = vip->vii_gen;
 
-        ip->u.generic_ip = (void *)vip;
+        ip->i_private = vip;
         
 }
 
@@ -338,5 +338,5 @@ vxfs_read_inode(struct inode *ip)
 void
 vxfs_clear_inode(struct inode *ip)
 {
-        kmem_cache_free(vxfs_inode_cachep, ip->u.generic_ip);
+        kmem_cache_free(vxfs_inode_cachep, ip->i_private);
 }
diff --git a/fs/fuse/control.c b/fs/fuse/control.c
index 46fe60b2da23..79ec1f23d4d2 100644
--- a/fs/fuse/control.c
+++ b/fs/fuse/control.c
@@ -23,7 +23,7 @@ static struct fuse_conn *fuse_ctl_file_conn_get(struct file *file)
 {
         struct fuse_conn *fc;
         mutex_lock(&fuse_mutex);
-        fc = file->f_dentry->d_inode->u.generic_ip;
+        fc = file->f_dentry->d_inode->i_private;
         if (fc)
                 fc = fuse_conn_get(fc);
         mutex_unlock(&fuse_mutex);
@@ -98,7 +98,7 @@ static struct dentry *fuse_ctl_add_dentry(struct dentry *parent,
                 inode->i_op = iop;
         inode->i_fop = fop;
         inode->i_nlink = nlink;
-        inode->u.generic_ip = fc;
+        inode->i_private = fc;
         d_add(dentry, inode);
         return dentry;
 }
@@ -150,7 +150,7 @@ void fuse_ctl_remove_conn(struct fuse_conn *fc)
 
         for (i = fc->ctl_ndents - 1; i >= 0; i--) {
                 struct dentry *dentry = fc->ctl_dentry[i];
-                dentry->d_inode->u.generic_ip = NULL;
+                dentry->d_inode->i_private = NULL;
                 d_drop(dentry);
                 dput(dentry);
         }
diff --git a/fs/inode.c b/fs/inode.c
index 0bf9f0444a96..77e254792025 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -163,7 +163,7 @@ static struct inode *alloc_inode(struct super_block *sb)
                                 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
                         mapping->backing_dev_info = bdi;
                 }
-                memset(&inode->u, 0, sizeof(inode->u));
+                inode->i_private = 0;
                 inode->i_mapping = mapping;
         }
         return inode;
diff --git a/fs/jffs/inode-v23.c b/fs/jffs/inode-v23.c
index b59553d28d13..7358ef87f16b 100644
--- a/fs/jffs/inode-v23.c
+++ b/fs/jffs/inode-v23.c
@@ -369,7 +369,7 @@ jffs_new_inode(const struct inode * dir, struct jffs_raw_inode *raw_inode,
 
         f = jffs_find_file(c, raw_inode->ino);
 
-        inode->u.generic_ip = (void *)f;
+        inode->i_private = (void *)f;
         insert_inode_hash(inode);
 
         return inode;
@@ -442,7 +442,7 @@ jffs_rename(struct inode *old_dir, struct dentry *old_dentry,
         });
 
         result = -ENOTDIR;
-        if (!(old_dir_f = (struct jffs_file *)old_dir->u.generic_ip)) {
+        if (!(old_dir_f = old_dir->i_private)) {
                 D(printk("jffs_rename(): Old dir invalid.\n"));
                 goto jffs_rename_end;
         }
@@ -456,7 +456,7 @@ jffs_rename(struct inode *old_dir, struct dentry *old_dentry,
 
         /* Find the new directory.  */
         result = -ENOTDIR;
-        if (!(new_dir_f = (struct jffs_file *)new_dir->u.generic_ip)) {
+        if (!(new_dir_f = new_dir->i_private)) {
                 D(printk("jffs_rename(): New dir invalid.\n"));
                 goto jffs_rename_end;
         }
@@ -593,7 +593,7 @@ jffs_readdir(struct file *filp, void *dirent, filldir_t filldir)
                 }
                 else {
                         ddino = ((struct jffs_file *)
-                                 inode->u.generic_ip)->pino;
+                                 inode->i_private)->pino;
                 }
                 D3(printk("jffs_readdir(): \"..\" %u\n", ddino));
                 if (filldir(dirent, "..", 2, filp->f_pos, ddino, DT_DIR) < 0) {
@@ -604,7 +604,7 @@ jffs_readdir(struct file *filp, void *dirent, filldir_t filldir)
                 }
                 filp->f_pos++;
         }
-        f = ((struct jffs_file *)inode->u.generic_ip)->children;
+        f = ((struct jffs_file *)inode->i_private)->children;
 
         j = 2;
         while(f && (f->deleted || j++ < filp->f_pos )) {
@@ -668,7 +668,7 @@ jffs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
         }
 
         r = -EACCES;
-        if (!(d = (struct jffs_file *)dir->u.generic_ip)) {
+        if (!(d = (struct jffs_file *)dir->i_private)) {
                 D(printk("jffs_lookup(): No such inode! (%lu)\n",
                          dir->i_ino));
                 goto jffs_lookup_end;
@@ -739,7 +739,7 @@ jffs_do_readpage_nolock(struct file *file, struct page *page)
         unsigned long read_len;
         int result;
         struct inode *inode = (struct inode*)page->mapping->host;
-        struct jffs_file *f = (struct jffs_file *)inode->u.generic_ip;
+        struct jffs_file *f = (struct jffs_file *)inode->i_private;
         struct jffs_control *c = (struct jffs_control *)inode->i_sb->s_fs_info;
         int r;
         loff_t offset;
@@ -828,7 +828,7 @@ jffs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
         });
 
         lock_kernel();
-        dir_f = (struct jffs_file *)dir->u.generic_ip;
+        dir_f = dir->i_private;
 
         ASSERT(if (!dir_f) {
                 printk(KERN_ERR "jffs_mkdir(): No reference to a "
@@ -972,7 +972,7 @@ jffs_remove(struct inode *dir, struct dentry *dentry, int type)
                 kfree(_name);
         });
 
-        dir_f = (struct jffs_file *) dir->u.generic_ip;
+        dir_f = dir->i_private;
         c = dir_f->c;
 
         result = -ENOENT;
@@ -1082,7 +1082,7 @@ jffs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
         if (!old_valid_dev(rdev))
                 return -EINVAL;
         lock_kernel();
-        dir_f = (struct jffs_file *)dir->u.generic_ip;
+        dir_f = dir->i_private;
         c = dir_f->c;
 
         D3(printk (KERN_NOTICE "mknod(): down biglock\n"));
@@ -1186,7 +1186,7 @@ jffs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
                 kfree(_symname);
         });
 
-        dir_f = (struct jffs_file *)dir->u.generic_ip;
+        dir_f = dir->i_private;
         ASSERT(if (!dir_f) {
                 printk(KERN_ERR "jffs_symlink(): No reference to a "
                        "jffs_file struct in inode.\n");
@@ -1289,7 +1289,7 @@ jffs_create(struct inode *dir, struct dentry *dentry, int mode,
                 kfree(s);
         });
 
-        dir_f = (struct jffs_file *)dir->u.generic_ip;
+        dir_f = dir->i_private;
         ASSERT(if (!dir_f) {
                 printk(KERN_ERR "jffs_create(): No reference to a "
                        "jffs_file struct in inode.\n");
@@ -1403,9 +1403,9 @@ jffs_file_write(struct file *filp, const char *buf, size_t count,
                 goto out_isem;
         }
 
-        if (!(f = (struct jffs_file *)inode->u.generic_ip)) {
-                D(printk("jffs_file_write(): inode->u.generic_ip = 0x%p\n",
-                                inode->u.generic_ip));
+        if (!(f = inode->i_private)) {
+                D(printk("jffs_file_write(): inode->i_private = 0x%p\n",
+                                inode->i_private));
                 goto out_isem;
         }
 
@@ -1693,7 +1693,7 @@ jffs_read_inode(struct inode *inode)
                 mutex_unlock(&c->fmc->biglock);
                 return;
         }
-        inode->u.generic_ip = (void *)f;
+        inode->i_private = f;
         inode->i_mode = f->mode;
         inode->i_nlink = f->nlink;
         inode->i_uid = f->uid;
@@ -1748,7 +1748,7 @@ jffs_delete_inode(struct inode *inode)
         lock_kernel();
         inode->i_size = 0;
         inode->i_blocks = 0;
-        inode->u.generic_ip = NULL;
+        inode->i_private = NULL;
         clear_inode(inode);
         if (inode->i_nlink == 0) {
                 c = (struct jffs_control *) inode->i_sb->s_fs_info;
diff --git a/fs/libfs.c b/fs/libfs.c
index ac02ea602c3d..2751793beeaa 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -547,7 +547,7 @@ int simple_attr_open(struct inode *inode, struct file *file,
 
         attr->get = get;
         attr->set = set;
-        attr->data = inode->u.generic_ip;
+        attr->data = inode->i_private;
         attr->fmt = fmt;
         mutex_init(&attr->mutex);
 
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index de887063dcfc..8801e41afe80 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -2052,7 +2052,7 @@ static int ocfs2_dlm_debug_open(struct inode *inode, struct file *file)
                 mlog_errno(ret);
                 goto out;
         }
-        osb = (struct ocfs2_super *) inode->u.generic_ip;
+        osb = inode->i_private;
         ocfs2_get_dlm_debug(osb->osb_dlm_debug);
         priv->p_dlm_debug = osb->osb_dlm_debug;
         INIT_LIST_HEAD(&priv->p_iter_res.l_debug_list);