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Per-mount allocated_ptys

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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: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sukadev Bhattiprolu 2009-01-02 13:41:21 +00:00 committed by Linus Torvalds
parent 59e55e6cf8
commit e76b7c01e5
1 changed files with 48 additions and 7 deletions
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55
fs/devpts/inode.c
View file

@ -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);
}