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authorTheodore Ts'o <tytso@mit.edu>2009-05-21 16:01:00 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2009-06-11 21:36:09 -0400
commit9fd5746fd3d7838bf6ff991d50f1257057d1156f (patch)
treee0afe14ea9415b0e54c40703bb44acfec100a4b3 /fs/char_dev.c
parentebc1ac164560a241d9bf1b7519062910c3f90a01 (diff)
downloadlinux-9fd5746fd3d7838bf6ff991d50f1257057d1156f.tar.gz
fs: Remove i_cindex from struct inode
The only user of the i_cindex element in the inode structure is used is by the firewire drivers. As part of an attempt to slim down the inode structure to save memory --- since a typical Linux system will have hundreds of thousands if not millions of inodes cached, a reduction in the size inode has high leverage. The firewire driver does not need i_cindex in any fast path, so it's simple enough to calculate when it is needed, instead of wasting space in the inode structure. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: krh@redhat.com Cc: stefanr@s5r6.in-berlin.de Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/char_dev.c')
-rw-r--r--fs/char_dev.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/fs/char_dev.c b/fs/char_dev.c
index 38f71222a55..b7c9d5187a7 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -375,7 +375,6 @@ static int chrdev_open(struct inode *inode, struct file *filp)
p = inode->i_cdev;
if (!p) {
inode->i_cdev = p = new;
- inode->i_cindex = idx;
list_add(&inode->i_devices, &p->list);
new = NULL;
} else if (!cdev_get(p))
@@ -405,6 +404,18 @@ static int chrdev_open(struct inode *inode, struct file *filp)
return ret;
}
+int cdev_index(struct inode *inode)
+{
+ int idx;
+ struct kobject *kobj;
+
+ kobj = kobj_lookup(cdev_map, inode->i_rdev, &idx);
+ if (!kobj)
+ return -1;
+ kobject_put(kobj);
+ return idx;
+}
+
void cd_forget(struct inode *inode)
{
spin_lock(&cdev_lock);
@@ -557,6 +568,7 @@ EXPORT_SYMBOL(cdev_init);
EXPORT_SYMBOL(cdev_alloc);
EXPORT_SYMBOL(cdev_del);
EXPORT_SYMBOL(cdev_add);
+EXPORT_SYMBOL(cdev_index);
EXPORT_SYMBOL(register_chrdev);
EXPORT_SYMBOL(unregister_chrdev);
EXPORT_SYMBOL(directly_mappable_cdev_bdi);