Commit 9a0e3eea authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 12566cc3 67245ff3

drivers/tty/pty.c

+30 −33
Original line number Diff line number Diff line
@@ -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;

	index = devpts_new_index(fsi);

	mutex_unlock(&devpts_mutex);

		goto err_file;

	}



	mutex_unlock(&devpts_mutex);

	retval = index;

	if (index < 0)

		goto out_put_ref;





	mutex_lock(&tty_mutex);

	tty = tty_init_dev(ptm_driver, index);



	if (IS_ERR(tty)) {

		retval = PTR_ERR(tty);

		goto out;

	}



	/* 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;

}

fs/devpts/inode.c

+24 −25
Original line number Diff line number Diff line
@@ -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);

include/linux/devpts_fs.h

+10 −24
Original line number Diff line number Diff line
@@ -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

CRA Git | Maintained and supported by SUSTech CRA and CCSE