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| author | Theodore Ts'o <tytso@mit.edu> | 2009-05-21 16:01:00 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2009-06-11 21:36:09 -0400 |
| commit | 9fd5746fd3d7838bf6ff991d50f1257057d1156f (patch) | |
| tree | e0afe14ea9415b0e54c40703bb44acfec100a4b3 /fs | |
| parent | ebc1ac164560a241d9bf1b7519062910c3f90a01 (diff) | |
| download | lwn-9fd5746fd3d7838bf6ff991d50f1257057d1156f.tar.gz lwn-9fd5746fd3d7838bf6ff991d50f1257057d1156f.zip | |
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')
| -rw-r--r-- | fs/char_dev.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/fs/char_dev.c b/fs/char_dev.c index 38f71222a552..b7c9d5187a75 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); |