Messages in this thread Patch in this message | | | Date | Sat, 12 Apr 2008 10:33:27 -0700 | From | sukadev@us ... | Subject | [PATCH 3/4]: Move devpts globals into init_pts_ns |
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Matt, Serge, please sign-off on this version. --- From: Sukadev Bhattiprolu <sukadev@us.ibm.com> Subject: [PATCH 3/4]: Move devpts globals into init_pts_ns
Move devpts global variables 'allocated_ptys' and 'devpts_mnt' into a new 'pts_namespace' and remove the 'devpts_root'.
Changelog: - Split these relatively simpler changes off from the patch that supports remounting devpts.
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> --- fs/devpts/inode.c | 84 ++++++++++++++++++++++++++++++++-------------- include/linux/devpts_fs.h | 10 +++++ 2 files changed, 70 insertions(+), 24 deletions(-)
Index: 2.6.25-rc8-mm1/fs/devpts/inode.c =================================================================== --- 2.6.25-rc8-mm1.orig/fs/devpts/inode.c 2008-04-11 10:12:09.000000000 -0700 +++ 2.6.25-rc8-mm1/fs/devpts/inode.c 2008-04-12 10:10:33.000000000 -0700 @@ -28,12 +28,8 @@ #define DEVPTS_DEFAULT_MODE 0600 extern int pty_limit; /* Config limit on Unix98 ptys */ -static DEFINE_IDR(allocated_ptys); static DECLARE_MUTEX(allocated_ptys_lock); -static struct vfsmount *devpts_mnt; -static struct dentry *devpts_root; - static struct { int setuid; int setgid; @@ -54,6 +50,14 @@ static match_table_t tokens = { {Opt_err, NULL} }; +struct pts_namespace init_pts_ns = { + .kref = { + .refcount = ATOMIC_INIT(2), + }, + .allocated_ptys = IDR_INIT(init_pts_ns.allocated_ptys), + .mnt = NULL, +}; + static int devpts_remount(struct super_block *sb, int *flags, char *data) { char *p; @@ -140,7 +144,7 @@ devpts_fill_super(struct super_block *s, inode->i_fop = &simple_dir_operations; inode->i_nlink = 2; - devpts_root = s->s_root = d_alloc_root(inode); + s->s_root = d_alloc_root(inode); if (s->s_root) return 0; @@ -168,10 +172,9 @@ static struct file_system_type devpts_fs * to the System V naming convention */ -static struct dentry *get_node(int num) +static struct dentry *get_node(struct dentry *root, int num) { char s[12]; - struct dentry *root = devpts_root; mutex_lock(&root->d_inode->i_mutex); return lookup_one_len(s, root, sprintf(s, "%d", num)); } @@ -180,14 +183,17 @@ int devpts_new_index(void) { int index; int idr_ret; + struct pts_namespace *pts_ns; + + pts_ns = &init_pts_ns; retry: - if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { + if (!idr_pre_get(&pts_ns->allocated_ptys, GFP_KERNEL)) { return -ENOMEM; } down(&allocated_ptys_lock); - idr_ret = idr_get_new(&allocated_ptys, NULL, &index); + idr_ret = idr_get_new(&pts_ns->allocated_ptys, NULL, &index); if (idr_ret < 0) { up(&allocated_ptys_lock); if (idr_ret == -EAGAIN) @@ -196,7 +202,7 @@ retry: } if (index >= pty_limit) { - idr_remove(&allocated_ptys, index); + idr_remove(&pts_ns->allocated_ptys, index); up(&allocated_ptys_lock); return -EIO; } @@ -206,8 +212,10 @@ retry: void devpts_kill_index(int idx) { + struct pts_namespace *pts_ns = &init_pts_ns; + down(&allocated_ptys_lock); - idr_remove(&allocated_ptys, idx); + idr_remove(&pts_ns->allocated_ptys, idx); up(&allocated_ptys_lock); } @@ -217,12 +225,26 @@ int devpts_pty_new(struct tty_struct *tt struct tty_driver *driver = tty->driver; dev_t device = MKDEV(driver->major, driver->minor_start+number); struct dentry *dentry; - struct inode *inode = new_inode(devpts_mnt->mnt_sb); + struct dentry *root; + struct inode *inode; + struct pts_namespace *pts_ns; /* We're supposed to be given the slave end of a pty */ BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY); BUG_ON(driver->subtype != PTY_TYPE_SLAVE); + pts_ns = &init_pts_ns; + root = pts_ns->mnt->mnt_root; + + mutex_lock(&root->d_inode->i_mutex); + inode = idr_find(&pts_ns->allocated_ptys, number); + mutex_unlock(&root->d_inode->i_mutex); + + if (inode && !IS_ERR(inode)) + return -EEXIST; + + inode = new_inode(pts_ns->mnt->mnt_sb); + if (!inode) return -ENOMEM; @@ -232,23 +254,28 @@ int devpts_pty_new(struct tty_struct *tt inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; init_special_inode(inode, S_IFCHR|config.mode, device); inode->i_private = tty; + idr_replace(&pts_ns->allocated_ptys, inode, number); - dentry = get_node(number); + dentry = get_node(root, number); if (!IS_ERR(dentry) && !dentry->d_inode) { d_instantiate(dentry, inode); - fsnotify_create(devpts_root->d_inode, dentry); + fsnotify_create(root->d_inode, dentry); } - mutex_unlock(&devpts_root->d_inode->i_mutex); + mutex_unlock(&root->d_inode->i_mutex); return 0; } struct tty_struct *devpts_get_tty(int number) { - struct dentry *dentry = get_node(number); + struct dentry *root; + struct dentry *dentry; struct tty_struct *tty; + root = init_pts_ns.mnt->mnt_root; + dentry = get_node(root, number); + tty = NULL; if (!IS_ERR(dentry)) { if (dentry->d_inode) @@ -256,14 +283,18 @@ struct tty_struct *devpts_get_tty(int nu dput(dentry); } - mutex_unlock(&devpts_root->d_inode->i_mutex); + mutex_unlock(&root->d_inode->i_mutex); return tty; } void devpts_pty_kill(int number) { - struct dentry *dentry = get_node(number); + struct dentry *root; + struct dentry *dentry; + + root = init_pts_ns.mnt->mnt_root; + dentry = get_node(root, number); if (!IS_ERR(dentry)) { struct inode *inode = dentry->d_inode; @@ -274,16 +305,21 @@ void devpts_pty_kill(int number) } dput(dentry); } - mutex_unlock(&devpts_root->d_inode->i_mutex); + mutex_unlock(&root->d_inode->i_mutex); } static int __init init_devpts_fs(void) { - int err = register_filesystem(&devpts_fs_type); + struct vfsmount *mnt; + int err; + + err = register_filesystem(&devpts_fs_type); if (!err) { - devpts_mnt = kern_mount(&devpts_fs_type); - if (IS_ERR(devpts_mnt)) - err = PTR_ERR(devpts_mnt); + mnt = kern_mount(&devpts_fs_type); + if (IS_ERR(mnt)) + err = PTR_ERR(mnt); + else + init_pts_ns.mnt = mnt; } return err; } @@ -291,7 +327,7 @@ static int __init init_devpts_fs(void) static void __exit exit_devpts_fs(void) { unregister_filesystem(&devpts_fs_type); - mntput(devpts_mnt); + mntput(init_pts_ns.mnt); } module_init(init_devpts_fs) Index: 2.6.25-rc8-mm1/include/linux/devpts_fs.h =================================================================== --- 2.6.25-rc8-mm1.orig/include/linux/devpts_fs.h 2008-04-11 10:34:16.000000000 -0700 +++ 2.6.25-rc8-mm1/include/linux/devpts_fs.h 2008-04-12 08:52:57.000000000 -0700 @@ -14,6 +14,16 @@ #define _LINUX_DEVPTS_FS_H #include <linux/errno.h> +#include <linux/kref.h> +#include <linux/idr.h> + +struct pts_namespace { + struct kref kref; + struct idr allocated_ptys; + struct vfsmount *mnt; +}; + +extern struct pts_namespace init_pts_ns; #ifdef CONFIG_UNIX98_PTYS
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