Merge branch 'ptmx-cleanup'
Merge the ptmx internal interface cleanup branch. This doesn't change semantics, but it should be a sane basis for eventually getting the multi-instance devpts code into some sane shape where we can get rid of the kernel config option. Which we can hopefully get done next merge window.. * ptmx-cleanup: devpts: clean up interface to pty drivers
This commit is contained in:
Linus Torvalds
Коммит
9a0e3eea25
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@ -663,14 +663,14 @@ static int pty_unix98_install(struct tty_driver *driver, struct tty_struct *tty)
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/* this is called once with whichever end is closed last */
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static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
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{
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struct inode *ptmx_inode;
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struct pts_fs_info *fsi;
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if (tty->driver->subtype == PTY_TYPE_MASTER)
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ptmx_inode = tty->driver_data;
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fsi = tty->driver_data;
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else
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ptmx_inode = tty->link->driver_data;
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devpts_kill_index(ptmx_inode, tty->index);
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devpts_del_ref(ptmx_inode);
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fsi = tty->link->driver_data;
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devpts_kill_index(fsi, tty->index);
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devpts_put_ref(fsi);
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}
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static const struct tty_operations ptm_unix98_ops = {
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@ -720,6 +720,7 @@ static const struct tty_operations pty_unix98_ops = {
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static int ptmx_open(struct inode *inode, struct file *filp)
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{
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struct pts_fs_info *fsi;
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struct tty_struct *tty;
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struct inode *slave_inode;
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int retval;
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@ -734,47 +735,41 @@ static int ptmx_open(struct inode *inode, struct file *filp)
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if (retval)
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return retval;
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fsi = devpts_get_ref(inode, filp);
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retval = -ENODEV;
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if (!fsi)
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goto out_free_file;
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/* find a device that is not in use. */
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mutex_lock(&devpts_mutex);
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index = devpts_new_index(inode);
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if (index < 0) {
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retval = index;
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mutex_unlock(&devpts_mutex);
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goto err_file;
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}
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index = devpts_new_index(fsi);
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mutex_unlock(&devpts_mutex);
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retval = index;
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if (index < 0)
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goto out_put_ref;
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mutex_lock(&tty_mutex);
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tty = tty_init_dev(ptm_driver, index);
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if (IS_ERR(tty)) {
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retval = PTR_ERR(tty);
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goto out;
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}
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/* The tty returned here is locked so we can safely
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drop the mutex */
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mutex_unlock(&tty_mutex);
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set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
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tty->driver_data = inode;
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retval = PTR_ERR(tty);
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if (IS_ERR(tty))
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goto out;
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/*
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* In the case where all references to ptmx inode are dropped and we
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* still have /dev/tty opened pointing to the master/slave pair (ptmx
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* is closed/released before /dev/tty), we must make sure that the inode
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* is still valid when we call the final pty_unix98_shutdown, thus we
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* hold an additional reference to the ptmx inode. For the same /dev/tty
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* last close case, we also need to make sure the super_block isn't
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* destroyed (devpts instance unmounted), before /dev/tty is closed and
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* on its release devpts_kill_index is called.
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* From here on out, the tty is "live", and the index and
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* fsi will be killed/put by the tty_release()
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*/
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devpts_add_ref(inode);
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set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
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tty->driver_data = fsi;
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tty_add_file(tty, filp);
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slave_inode = devpts_pty_new(inode,
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slave_inode = devpts_pty_new(fsi,
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MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index,
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tty->link);
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if (IS_ERR(slave_inode)) {
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@ -793,12 +788,14 @@ static int ptmx_open(struct inode *inode, struct file *filp)
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return 0;
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err_release:
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tty_unlock(tty);
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// This will also put-ref the fsi
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tty_release(inode, filp);
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return retval;
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out:
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mutex_unlock(&tty_mutex);
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devpts_kill_index(inode, index);
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err_file:
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devpts_kill_index(fsi, index);
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out_put_ref:
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devpts_put_ref(fsi);
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out_free_file:
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tty_free_file(filp);
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return retval;
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}
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@ -128,6 +128,7 @@ static const match_table_t tokens = {
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struct pts_fs_info {
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struct ida allocated_ptys;
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struct pts_mount_opts mount_opts;
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struct super_block *sb;
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struct dentry *ptmx_dentry;
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};
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@ -358,7 +359,7 @@ static const struct super_operations devpts_sops = {
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.show_options = devpts_show_options,
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};
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static void *new_pts_fs_info(void)
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static void *new_pts_fs_info(struct super_block *sb)
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{
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struct pts_fs_info *fsi;
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@ -369,6 +370,7 @@ static void *new_pts_fs_info(void)
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ida_init(&fsi->allocated_ptys);
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fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE;
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fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
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fsi->sb = sb;
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return fsi;
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}
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@ -384,7 +386,7 @@ devpts_fill_super(struct super_block *s, void *data, int silent)
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s->s_op = &devpts_sops;
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s->s_time_gran = 1;
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s->s_fs_info = new_pts_fs_info();
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s->s_fs_info = new_pts_fs_info(s);
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if (!s->s_fs_info)
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goto fail;
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@ -524,17 +526,14 @@ static struct file_system_type devpts_fs_type = {
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* to the System V naming convention
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*/
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int devpts_new_index(struct inode *ptmx_inode)
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int devpts_new_index(struct pts_fs_info *fsi)
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{
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struct super_block *sb = pts_sb_from_inode(ptmx_inode);
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struct pts_fs_info *fsi;
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int index;
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int ida_ret;
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if (!sb)
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if (!fsi)
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return -ENODEV;
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fsi = DEVPTS_SB(sb);
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retry:
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if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL))
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return -ENOMEM;
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@ -564,11 +563,8 @@ retry:
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return index;
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}
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void devpts_kill_index(struct inode *ptmx_inode, int idx)
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void devpts_kill_index(struct pts_fs_info *fsi, int idx)
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{
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struct super_block *sb = pts_sb_from_inode(ptmx_inode);
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struct pts_fs_info *fsi = DEVPTS_SB(sb);
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mutex_lock(&allocated_ptys_lock);
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ida_remove(&fsi->allocated_ptys, idx);
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pty_count--;
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@ -578,21 +574,25 @@ void devpts_kill_index(struct inode *ptmx_inode, int idx)
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/*
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* pty code needs to hold extra references in case of last /dev/tty close
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*/
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void devpts_add_ref(struct inode *ptmx_inode)
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struct pts_fs_info *devpts_get_ref(struct inode *ptmx_inode, struct file *file)
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{
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struct super_block *sb = pts_sb_from_inode(ptmx_inode);
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struct super_block *sb;
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struct pts_fs_info *fsi;
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sb = pts_sb_from_inode(ptmx_inode);
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if (!sb)
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return NULL;
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fsi = DEVPTS_SB(sb);
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if (!fsi)
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return NULL;
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atomic_inc(&sb->s_active);
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ihold(ptmx_inode);
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return fsi;
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}
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void devpts_del_ref(struct inode *ptmx_inode)
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void devpts_put_ref(struct pts_fs_info *fsi)
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{
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struct super_block *sb = pts_sb_from_inode(ptmx_inode);
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iput(ptmx_inode);
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deactivate_super(sb);
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deactivate_super(fsi->sb);
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}
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/**
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@ -604,22 +604,21 @@ void devpts_del_ref(struct inode *ptmx_inode)
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*
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* The created inode is returned. Remove it from /dev/pts/ by devpts_pty_kill.
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*/
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struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index,
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struct inode *devpts_pty_new(struct pts_fs_info *fsi, dev_t device, int index,
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void *priv)
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{
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struct dentry *dentry;
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struct super_block *sb = pts_sb_from_inode(ptmx_inode);
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struct super_block *sb;
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struct inode *inode;
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struct dentry *root;
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struct pts_fs_info *fsi;
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struct pts_mount_opts *opts;
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char s[12];
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if (!sb)
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if (!fsi)
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return ERR_PTR(-ENODEV);
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sb = fsi->sb;
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root = sb->s_root;
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fsi = DEVPTS_SB(sb);
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opts = &fsi->mount_opts;
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inode = new_inode(sb);
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@ -15,38 +15,24 @@
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#include <linux/errno.h>
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struct pts_fs_info;
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#ifdef CONFIG_UNIX98_PTYS
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int devpts_new_index(struct inode *ptmx_inode);
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void devpts_kill_index(struct inode *ptmx_inode, int idx);
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void devpts_add_ref(struct inode *ptmx_inode);
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void devpts_del_ref(struct inode *ptmx_inode);
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/* Look up a pts fs info and get a ref to it */
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struct pts_fs_info *devpts_get_ref(struct inode *, struct file *);
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void devpts_put_ref(struct pts_fs_info *);
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int devpts_new_index(struct pts_fs_info *);
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void devpts_kill_index(struct pts_fs_info *, int);
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/* mknod in devpts */
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struct inode *devpts_pty_new(struct inode *ptmx_inode, dev_t device, int index,
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void *priv);
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struct inode *devpts_pty_new(struct pts_fs_info *, dev_t, int, void *);
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/* get private structure */
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void *devpts_get_priv(struct inode *pts_inode);
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/* unlink */
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void devpts_pty_kill(struct inode *inode);
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#else
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/* Dummy stubs in the no-pty case */
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static inline int devpts_new_index(struct inode *ptmx_inode) { return -EINVAL; }
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static inline void devpts_kill_index(struct inode *ptmx_inode, int idx) { }
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static inline void devpts_add_ref(struct inode *ptmx_inode) { }
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static inline void devpts_del_ref(struct inode *ptmx_inode) { }
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static inline struct inode *devpts_pty_new(struct inode *ptmx_inode,
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dev_t device, int index, void *priv)
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{
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return ERR_PTR(-EINVAL);
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}
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static inline void *devpts_get_priv(struct inode *pts_inode)
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{
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return NULL;
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}
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static inline void devpts_pty_kill(struct inode *inode) { }
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#endif
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