[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/drivers/misc/ibmasm/ibmasmfs.c b/drivers/misc/ibmasm/ibmasmfs.c
index 4a35caf..0e909b6 100644
--- a/drivers/misc/ibmasm/ibmasmfs.c
+++ b/drivers/misc/ibmasm/ibmasmfs.c
@@ -175,7 +175,7 @@
}
inode->i_fop = fops;
- inode->u.generic_ip = data;
+ inode->i_private = data;
d_add(dentry, inode);
return dentry;
@@ -244,7 +244,7 @@
{
struct ibmasmfs_command_data *command_data;
- if (!inode->u.generic_ip)
+ if (!inode->i_private)
return -ENODEV;
command_data = kmalloc(sizeof(struct ibmasmfs_command_data), GFP_KERNEL);
@@ -252,7 +252,7 @@
return -ENOMEM;
command_data->command = NULL;
- command_data->sp = inode->u.generic_ip;
+ command_data->sp = inode->i_private;
file->private_data = command_data;
return 0;
}
@@ -351,10 +351,10 @@
struct ibmasmfs_event_data *event_data;
struct service_processor *sp;
- if (!inode->u.generic_ip)
+ if (!inode->i_private)
return -ENODEV;
- sp = inode->u.generic_ip;
+ sp = inode->i_private;
event_data = kmalloc(sizeof(struct ibmasmfs_event_data), GFP_KERNEL);
if (!event_data)
@@ -439,14 +439,14 @@
{
struct ibmasmfs_heartbeat_data *rhbeat;
- if (!inode->u.generic_ip)
+ if (!inode->i_private)
return -ENODEV;
rhbeat = kmalloc(sizeof(struct ibmasmfs_heartbeat_data), GFP_KERNEL);
if (!rhbeat)
return -ENOMEM;
- rhbeat->sp = (struct service_processor *)inode->u.generic_ip;
+ rhbeat->sp = inode->i_private;
rhbeat->active = 0;
ibmasm_init_reverse_heartbeat(rhbeat->sp, &rhbeat->heartbeat);
file->private_data = rhbeat;
@@ -508,7 +508,7 @@
static int remote_settings_file_open(struct inode *inode, struct file *file)
{
- file->private_data = inode->u.generic_ip;
+ file->private_data = inode->i_private;
return 0;
}