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

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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>
This commit is contained in:
Theodore Ts'o
2006-09-27 01:50:46 -07:00
committed by Linus Torvalds
parent 6a1d9805ec
commit 8e18e2941c
36 changed files with 88 additions and 90 deletions
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16
drivers/misc/ibmasm/ibmasmfs.c
View File

@ -175,7 +175,7 @@ static struct dentry *ibmasmfs_create_file (struct super_block *sb,
}
inode->i_fop = fops;
inode->u.generic_ip = data;
inode->i_private = data;
d_add(dentry, inode);
return dentry;
@ -244,7 +244,7 @@ static int command_file_open(struct inode *inode, struct file *file)
{
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 @@ static int command_file_open(struct inode *inode, struct file *file)
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 @@ static int event_file_open(struct inode *inode, struct file *file)
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 @@ static int r_heartbeat_file_open(struct inode *inode, struct file *file)
{
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 ssize_t r_heartbeat_file_write(struct file *file, const char __user *buf,
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;
}