[PATCH 02/21] TTY: devpts, return created inode from devpts_pty_new

From: Jiri Slaby
Date: Thu Oct 18 2012 - 16:30:22 EST


The goal is to stop setting and using tty->driver_data in devpts code.
It should be used solely by the driver's code, pty in this case.

For the cleanup of layering, we will need the inode created in
devpts_pty_new to be stored into slave's driver_data. So we convert
devpts_pty_new to return the inode or an ERR_PTR-encoded error in case
of failure.

The move of 'inode = new_inode(sb);' from declarators to the code is
only cosmetical, but it makes the code easier to read.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/tty/pty.c | 7 +++++--
fs/devpts/inode.c | 12 ++++++------
include/linux/devpts_fs.h | 8 ++++----
3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 65f7671..9985b45 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -614,6 +614,7 @@ static const struct tty_operations pty_unix98_ops = {
static int ptmx_open(struct inode *inode, struct file *filp)
{
struct tty_struct *tty;
+ struct inode *slave_inode;
int retval;
int index;

@@ -650,9 +651,11 @@ static int ptmx_open(struct inode *inode, struct file *filp)

tty_add_file(tty, filp);

- retval = devpts_pty_new(inode, tty->link);
- if (retval)
+ slave_inode = devpts_pty_new(inode, tty->link);
+ if (IS_ERR(slave_inode)) {
+ retval = PTR_ERR(slave_inode);
goto err_release;
+ }

retval = ptm_driver->ops->open(tty, filp);
if (retval)
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 4796580..ec3bab7 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -545,7 +545,7 @@ void devpts_kill_index(struct inode *ptmx_inode, int idx)
mutex_unlock(&allocated_ptys_lock);
}

-int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
+struct inode *devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
{
/* tty layer puts index from devpts_new_index() in here */
int number = tty->index;
@@ -553,19 +553,19 @@ int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
dev_t device = MKDEV(driver->major, driver->minor_start+number);
struct dentry *dentry;
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
- struct inode *inode = new_inode(sb);
+ struct inode *inode;
struct dentry *root = sb->s_root;
struct pts_fs_info *fsi = DEVPTS_SB(sb);
struct pts_mount_opts *opts = &fsi->mount_opts;
- int ret = 0;
char s[12];

/* We're supposed to be given the slave end of a pty */
BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY);
BUG_ON(driver->subtype != PTY_TYPE_SLAVE);

+ inode = new_inode(sb);
if (!inode)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);

inode->i_ino = number + 3;
inode->i_uid = opts->setuid ? opts->uid : current_fsuid();
@@ -585,12 +585,12 @@ int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
fsnotify_create(root->d_inode, dentry);
} else {
iput(inode);
- ret = -ENOMEM;
+ inode = ERR_PTR(-ENOMEM);
}

mutex_unlock(&root->d_inode->i_mutex);

- return ret;
+ return inode;
}

void *devpts_get_priv(struct inode *pts_inode)
diff --git a/include/linux/devpts_fs.h b/include/linux/devpts_fs.h
index de635a5..4ca846f 100644
--- a/include/linux/devpts_fs.h
+++ b/include/linux/devpts_fs.h
@@ -20,7 +20,7 @@
int devpts_new_index(struct inode *ptmx_inode);
void devpts_kill_index(struct inode *ptmx_inode, int idx);
/* mknod in devpts */
-int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty);
+struct inode *devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty);
/* get private structure */
void *devpts_get_priv(struct inode *pts_inode);
/* unlink */
@@ -31,10 +31,10 @@ void devpts_pty_kill(struct tty_struct *tty);
/* Dummy stubs in the no-pty case */
static inline int devpts_new_index(struct inode *ptmx_inode) { return -EINVAL; }
static inline void devpts_kill_index(struct inode *ptmx_inode, int idx) { }
-static inline int devpts_pty_new(struct inode *ptmx_inode,
- struct tty_struct *tty)
+static inline struct inode *devpts_pty_new(struct inode *ptmx_inode,
+ struct tty_struct *tty)
{
- return -EINVAL;
+ return ERR_PTR(-EINVAL);
}
static inline void *devpts_get_priv(struct inode *pts_inode)
{
--
1.7.12.3


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