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Commit e76b7c01 authored by Sukadev Bhattiprolu's avatar Sukadev Bhattiprolu Committed by Linus Torvalds
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Per-mount allocated_ptys 



To enable multiple mounts of devpts, 'allocated_ptys' must be a per-mount
variable rather than a global variable.  Move 'allocated_ptys' into the
super_block's s_fs_info.

Changelog[v2]:
	Define and use DEVPTS_SB() wrapper.

Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 59e55e6c

fs/devpts/inode.c

+48 −7
Original line number Diff line number Diff line
@@ -30,7 +30,6 @@ 
#define PTMX_MINOR	2



extern int pty_limit;			/* Config limit on Unix98 ptys */

static DEFINE_IDA(allocated_ptys);

static DEFINE_MUTEX(allocated_ptys_lock);



static struct vfsmount *devpts_mnt;
@@ -55,6 +54,15 @@ static const match_table_t tokens = { 
	{Opt_err, NULL}

};



struct pts_fs_info {

	struct ida allocated_ptys;

};



static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb)

{

	return sb->s_fs_info;

}



static inline struct super_block *pts_sb_from_inode(struct inode *inode)

{

	if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)
@@ -126,6 +134,19 @@ static const struct super_operations devpts_sops = { 
	.show_options	= devpts_show_options,

};



static void *new_pts_fs_info(void)

{

	struct pts_fs_info *fsi;



	fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL);

	if (!fsi)

		return NULL;



	ida_init(&fsi->allocated_ptys);



	return fsi;

}



static int

devpts_fill_super(struct super_block *s, void *data, int silent)

{
@@ -137,9 +158,13 @@ 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();

	if (!s->s_fs_info)

		goto fail;



	inode = new_inode(s);

	if (!inode)

		goto fail;

		goto free_fsi;

	inode->i_ino = 1;

	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;

	inode->i_blocks = 0;
@@ -155,6 +180,9 @@ devpts_fill_super(struct super_block *s, void *data, int silent) 
	

	printk("devpts: get root dentry failed\n");

	iput(inode);



free_fsi:

	kfree(s->s_fs_info);

fail:

	return -ENOMEM;

}
@@ -165,11 +193,19 @@ static int devpts_get_sb(struct file_system_type *fs_type, 
	return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt);

}



static void devpts_kill_sb(struct super_block *sb)

{

	struct pts_fs_info *fsi = DEVPTS_SB(sb);



	kfree(fsi);

	kill_anon_super(sb);

}



static struct file_system_type devpts_fs_type = {

	.owner		= THIS_MODULE,

	.name		= "devpts",

	.get_sb		= devpts_get_sb,

	.kill_sb	= kill_anon_super,

	.kill_sb	= devpts_kill_sb,

};



/*
@@ -179,16 +215,18 @@ static struct file_system_type devpts_fs_type = { 


int devpts_new_index(struct inode *ptmx_inode)

{

	struct super_block *sb = pts_sb_from_inode(ptmx_inode);

	struct pts_fs_info *fsi = DEVPTS_SB(sb);

	int index;

	int ida_ret;



retry:

	if (!ida_pre_get(&allocated_ptys, GFP_KERNEL)) {

	if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL)) {

		return -ENOMEM;

	}



	mutex_lock(&allocated_ptys_lock);

	ida_ret = ida_get_new(&allocated_ptys, &index);

	ida_ret = ida_get_new(&fsi->allocated_ptys, &index);

	if (ida_ret < 0) {

		mutex_unlock(&allocated_ptys_lock);

		if (ida_ret == -EAGAIN)
@@ -197,7 +235,7 @@ int devpts_new_index(struct inode *ptmx_inode) 
	}



	if (index >= pty_limit) {

		ida_remove(&allocated_ptys, index);

		ida_remove(&fsi->allocated_ptys, index);

		mutex_unlock(&allocated_ptys_lock);

		return -EIO;

	}
@@ -207,8 +245,11 @@ int devpts_new_index(struct inode *ptmx_inode) 


void devpts_kill_index(struct inode *ptmx_inode, 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(&allocated_ptys, idx);

	ida_remove(&fsi->allocated_ptys, idx);

	mutex_unlock(&allocated_ptys_lock);

}