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-rw-r--r--drivers/tty/pty.c63
-rw-r--r--fs/devpts/inode.c49
-rw-r--r--include/linux/devpts_fs.h34
3 files changed, 64 insertions, 82 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index e16a49b..0058d9fb 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -663,14 +663,14 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
/* this is called once with whichever end is closed last */
static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
{
- struct inode *ptmx_inode;
+ struct pts_fs_info *fsi;
if (tty->driver->subtype == PTY_TYPE_MASTER)
- ptmx_inode = tty->driver_data;
+ fsi = tty->driver_data;
else
- ptmx_inode = tty->link->driver_data;
- devpts_kill_index(ptmx_inode, tty->index);
- devpts_del_ref(ptmx_inode);
+ fsi = tty->link->driver_data;
+ devpts_kill_index(fsi, tty->index);
+ devpts_put_ref(fsi);
}
static const struct tty_operations ptm_unix98_ops = {
@@ -720,6 +720,7 @@ static const struct tty_operations pty_unix98_ops = {
static int ptmx_open(struct inode *inode, struct file *filp)
{
+ struct pts_fs_info *fsi;
struct tty_struct *tty;
struct inode *slave_inode;
int retval;
@@ -734,47 +735,41 @@ static int ptmx_open(struct inode *inode, struct file *filp)
if (retval)
return retval;
+ fsi = devpts_get_ref(inode, filp);
+ retval = -ENODEV;
+ if (!fsi)
+ goto out_free_file;
+
/* find a device that is not in use. */
mutex_lock(&devpts_mutex);
- index = devpts_new_index(inode);
- if (index < 0) {
- retval = index;
- mutex_unlock(&devpts_mutex);
- goto err_file;
- }
-
+ index = devpts_new_index(fsi);
mutex_unlock(&devpts_mutex);
- mutex_lock(&tty_mutex);
- tty = tty_init_dev(ptm_driver, index);
+ retval = index;
+ if (index < 0)
+ goto out_put_ref;
- if (IS_ERR(tty)) {
- retval = PTR_ERR(tty);
- goto out;
- }
+ mutex_lock(&tty_mutex);
+ tty = tty_init_dev(ptm_driver, index);
/* The tty returned here is locked so we can safely
drop the mutex */
mutex_unlock(&tty_mutex);
- set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
- tty->driver_data = inode;
+ retval = PTR_ERR(tty);
+ if (IS_ERR(tty))
+ goto out;
/*
- * In the case where all references to ptmx inode are dropped and we
- * still have /dev/tty opened pointing to the master/slave pair (ptmx
- * is closed/released before /dev/tty), we must make sure that the inode
- * is still valid when we call the final pty_unix98_shutdown, thus we
- * hold an additional reference to the ptmx inode. For the same /dev/tty
- * last close case, we also need to make sure the super_block isn't
- * destroyed (devpts instance unmounted), before /dev/tty is closed and
- * on its release devpts_kill_index is called.
+ * From here on out, the tty is "live", and the index and
+ * fsi will be killed/put by the tty_release()
*/
- devpts_add_ref(inode);
+ set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
+ tty->driver_data = fsi;
tty_add_file(tty, filp);
- slave_inode = devpts_pty_new(inode,
+ slave_inode = devpts_pty_new(fsi,
MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index,
tty->link);
if (IS_ERR(slave_inode)) {
@@ -793,12 +788,14 @@ static int ptmx_open(struct inode *inode, struct file *filp)
return 0;
err_release:
tty_unlock(tty);
+ // This will also put-ref the fsi
tty_release(inode, filp);
return retval;
out:
- mutex_unlock(&tty_mutex);
- devpts_kill_index(inode, index);
-err_file:
+ devpts_kill_index(fsi, index);
+out_put_ref:
+ devpts_put_ref(fsi);
+out_free_file:
tty_free_file(filp);
return retval;
}
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 655f21f..0af8e7d 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -128,6 +128,7 @@ static const match_table_t tokens = {
struct pts_fs_info {
struct ida allocated_ptys;
struct pts_mount_opts mount_opts;
+ struct super_block *sb;
struct dentry *ptmx_dentry;
};
@@ -358,7 +359,7 @@ static const struct super_operations devpts_sops = {
.show_options = devpts_show_options,
};
-static void *new_pts_fs_info(void)
+static void *new_pts_fs_info(struct super_block *sb)
{
struct pts_fs_info *fsi;
@@ -369,6 +370,7 @@ static void *new_pts_fs_info(void)
ida_init(&fsi->allocated_ptys);
fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE;
fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
+ fsi->sb = sb;
return fsi;
}
@@ -384,7 +386,7 @@ devpts_fill_super(struct super_block *s, void *data, int silent)
s->s_op = &devpts_sops;
s->s_time_gran = 1;
- s->s_fs_info = new_pts_fs_info();
+ s->s_fs_info = new_pts_fs_info(s);
if (!s->s_fs_info)
goto fail;
@@ -524,17 +526,14 @@ static struct file_system_type devpts_fs_type = {
* to the System V naming convention
*/
-int devpts_new_index(struct inode *ptmx_inode)
+int devpts_new_index(struct pts_fs_info *fsi)
{
- struct super_block *sb = pts_sb_from_inode(ptmx_inode);
- struct pts_fs_info *fsi;
int index;
int ida_ret;
- if (!sb)
+ if (!fsi)
return -ENODEV;
- fsi = DEVPTS_SB(sb);
retry:
if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL))
return -ENOMEM;
@@ -564,11 +563,8 @@ retry:
return index;
}
-void devpts_kill_index(struct inode *ptmx_inode, int idx)
+void devpts_kill_index(struct pts_fs_info *fsi, int idx)
{
- struct super_block *sb = pts_sb_from_inode(ptmx_inode);
- struct pts_fs_info *fsi = DEVPTS_SB(sb);
-
mutex_lock(&allocated_ptys_lock);
ida_remove(&fsi->allocated_ptys, idx);
pty_count--;
@@ -578,21 +574,25 @@ void devpts_kill_index(struct inode *ptmx_inode, int idx)
/*
* pty code needs to hold extra references in case of last /dev/tty close
*/
-
-void devpts_add_ref(struct inode *ptmx_inode)
+struct pts_fs_info *devpts_get_ref(struct inode *ptmx_inode, struct file *file)
{
- struct super_block *sb = pts_sb_from_inode(ptmx_inode);
+ struct super_block *sb;
+ struct pts_fs_info *fsi;
+
+ sb = pts_sb_from_inode(ptmx_inode);
+ if (!sb)
+ return NULL;
+ fsi = DEVPTS_SB(sb);
+ if (!fsi)
+ return NULL;
atomic_inc(&sb->s_active);
- ihold(ptmx_inode);
+ return fsi;
}
-void devpts_del_ref(struct inode *ptmx_inode)
+void devpts_put_ref(struct pts_fs_info *fsi)
{
- struct super_block *sb = pts_sb_from_inode(ptmx_inode);
-
- iput(ptmx_inode);
- deactivate_super(sb);
+ deactivate_super(fsi->sb);
}
/**
@@ -604,22 +604,21 @@ void devpts_del_ref(struct inode *ptmx_inode)
*
* The created inode is returned. Remove it from /dev/pts/ by devpts_pty_kill.
*/
-struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index,
+struct inode *devpts_pty_new(struct pts_fs_info *fsi, dev_t device, int index,
void *priv)
{
struct dentry *dentry;
- struct super_block *sb = pts_sb_from_inode(ptmx_inode);
+ struct super_block *sb;
struct inode *inode;
struct dentry *root;
- struct pts_fs_info *fsi;
struct pts_mount_opts *opts;
char s[12];
- if (!sb)
+ if (!fsi)
return ERR_PTR(-ENODEV);
+ sb = fsi->sb;
root = sb->s_root;
- fsi = DEVPTS_SB(sb);
opts = &fsi->mount_opts;
inode = new_inode(sb);
diff --git a/include/linux/devpts_fs.h b/include/linux/devpts_fs.h
index e0ee0b3..358a4db 100644
--- a/include/linux/devpts_fs.h
+++ b/include/linux/devpts_fs.h
@@ -15,38 +15,24 @@
#include <linux/errno.h>
+struct pts_fs_info;
+
#ifdef CONFIG_UNIX98_PTYS
-int devpts_new_index(struct inode *ptmx_inode);
-void devpts_kill_index(struct inode *ptmx_inode, int idx);
-void devpts_add_ref(struct inode *ptmx_inode);
-void devpts_del_ref(struct inode *ptmx_inode);
+/* Look up a pts fs info and get a ref to it */
+struct pts_fs_info *devpts_get_ref(struct inode *, struct file *);
+void devpts_put_ref(struct pts_fs_info *);
+
+int devpts_new_index(struct pts_fs_info *);
+void devpts_kill_index(struct pts_fs_info *, int);
+
/* mknod in devpts */
-struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index,
- void *priv);
+struct inode *devpts_pty_new(struct pts_fs_info *, dev_t, int, void *);
/* get private structure */
void *devpts_get_priv(struct inode *pts_inode);
/* unlink */
void devpts_pty_kill(struct inode *inode);
-#else
-
-/* 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 void devpts_add_ref(struct inode *ptmx_inode) { }
-static inline void devpts_del_ref(struct inode *ptmx_inode) { }
-static inline struct inode *devpts_pty_new(struct inode *ptmx_inode,
- dev_t device, int index, void *priv)
-{
- return ERR_PTR(-EINVAL);
-}
-static inline void *devpts_get_priv(struct inode *pts_inode)
-{
- return NULL;
-}
-static inline void devpts_pty_kill(struct inode *inode) { }
-
#endif
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