[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>
diff --git a/fs/jffs/inode-v23.c b/fs/jffs/inode-v23.c
index b59553d..7358ef8 100644
--- a/fs/jffs/inode-v23.c
+++ b/fs/jffs/inode-v23.c
@@ -369,7 +369,7 @@
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 @@
});
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 @@
/* 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 @@
}
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 @@
}
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 @@
}
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 @@
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 @@
});
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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;