[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>
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committed by
Linus Torvalds

parent
6a1d9805ec
commit
8e18e2941c
@@ -44,8 +44,8 @@ static ssize_t default_write_file(struct file *file, const char __user *buf,
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static int default_open(struct inode *inode, struct file *file)
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{
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if (inode->u.generic_ip)
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file->private_data = inode->u.generic_ip;
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if (inode->i_private)
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file->private_data = inode->i_private;
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return 0;
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}
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@@ -194,7 +194,7 @@ static int create_by_name(const char *name, mode_t mode,
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* directory dentry if set. If this paramater is NULL, then the
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* file will be created in the root of the securityfs filesystem.
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* @data: a pointer to something that the caller will want to get to later
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* on. The inode.u.generic_ip pointer will point to this value on
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* on. The inode.i_private pointer will point to this value on
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* the open() call.
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* @fops: a pointer to a struct file_operations that should be used for
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* this file.
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@@ -240,7 +240,7 @@ struct dentry *securityfs_create_file(const char *name, mode_t mode,
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if (fops)
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dentry->d_inode->i_fop = fops;
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if (data)
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dentry->d_inode->u.generic_ip = data;
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dentry->d_inode->i_private = data;
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}
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exit:
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return dentry;
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