[PATCH 65/80] Simplify devpts_pty_kill

Alan Cox
2008-10-13T09:59:34Z

From: Sukadev Bhattiprolu <sukadev@us.ibm.com>

When creating a new pty, save the pty's inode in the tty->driver_data.
Use this inode in pty_kill() to identify the devpts instance. Since
we now have the inode for the pty, we can skip get_node() lookup and
remove the unused get_node().

TODO:
- check if the mutex_lock is needed in pty_kill().

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
---

fs/devpts/inode.c | 29 ++++++++++++-----------------
1 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 50e885f..a70d5d0 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -170,14 +170,6 @@ static struct file_system_type devpts_fs_type = {
* to the System V naming convention
*/

-static struct dentry *get_node(int num)
-{
- char s[12];
- struct dentry *root = devpts_root;
- mutex_lock(&root->d_inode->i_mutex);
- return lookup_one_len(s, root, sprintf(s, "%d", num));
-}
-
int devpts_new_index(struct inode *ptmx_inode)
{
int index;
@@ -235,6 +227,7 @@ int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
init_special_inode(inode, S_IFCHR|config.mode, device);
inode->i_private = tty;
+ tty->driver_data = inode;

sprintf(s, "%d", number);

@@ -262,18 +255,20 @@ struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number)

void devpts_pty_kill(struct tty_struct *tty)
{
- int number = tty->index;
- struct dentry *dentry = get_node(number);
+ struct inode *inode = tty->driver_data;
+ struct dentry *dentry;

- if (!IS_ERR(dentry)) {
- struct inode *inode = dentry->d_inode;
- if (inode) {
- inode->i_nlink--;
- d_delete(dentry);
- dput(dentry);
- }
+ BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR));
+
+ mutex_lock(&devpts_root->d_inode->i_mutex);
+
+ dentry = d_find_alias(inode);
+ if (dentry && !IS_ERR(dentry)) {
+ inode->i_nlink--;
+ d_delete(dentry);
dput(dentry);
}
+
mutex_unlock(&devpts_root->d_inode->i_mutex);
}