diff options
| -rw-r--r-- | drivers/tty/pty.c | 63 | ||||
| -rw-r--r-- | fs/devpts/inode.c | 49 | ||||
| -rw-r--r-- | include/linux/devpts_fs.h | 34 |
3 files changed, 64 insertions, 82 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index e16a49b507ef..0058d9fbf931 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 655f21f99160..0af8e7d70d27 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 e0ee0b3000b2..358a4db72a27 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 |