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tty: move pty count limiting into devpts

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Let's move this stuff to the better place, where we can account pty right in
tty-indexes managing code.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Konstantin Khlebnikov
2012-01-05 13:06:02 +04:00
committed by Greg Kroah-Hartman
parent 593a27c4b2
commit a4834c102f
2 changed files with 52 additions and 52 deletions
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53
fs/devpts/inode.c
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@@ -36,7 +36,52 @@
#define DEVPTS_DEFAULT_PTMX_MODE 0000
#define PTMX_MINOR 2
extern int pty_limit; /* Config limit on Unix98 ptys */
/*
* sysctl support for setting limits on the number of Unix98 ptys allocated.
* Otherwise one can eat up all kernel memory by opening /dev/ptmx repeatedly.
*/
static int pty_limit = NR_UNIX98_PTY_DEFAULT;
static int pty_limit_min;
static int pty_limit_max = NR_UNIX98_PTY_MAX;
static int pty_count;
static struct ctl_table pty_table[] = {
{
.procname = "max",
.maxlen = sizeof(int),
.mode = 0644,
.data = &pty_limit,
.proc_handler = proc_dointvec_minmax,
.extra1 = &pty_limit_min,
.extra2 = &pty_limit_max,
}, {
.procname = "nr",
.maxlen = sizeof(int),
.mode = 0444,
.data = &pty_count,
.proc_handler = proc_dointvec,
},
{}
};
static struct ctl_table pty_kern_table[] = {
{
.procname = "pty",
.mode = 0555,
.child = pty_table,
},
{}
};
static struct ctl_table pty_root_table[] = {
{
.procname = "kernel",
.mode = 0555,
.child = pty_kern_table,
},
{}
};
static DEFINE_MUTEX(allocated_ptys_lock);
static struct vfsmount *devpts_mnt;
@@ -451,6 +496,7 @@ retry:
mutex_unlock(&allocated_ptys_lock);
return -EIO;
}
pty_count++;
mutex_unlock(&allocated_ptys_lock);
return index;
}
@@ -462,6 +508,7 @@ void devpts_kill_index(struct inode *ptmx_inode, int idx)
mutex_lock(&allocated_ptys_lock);
ida_remove(&fsi->allocated_ptys, idx);
pty_count--;
mutex_unlock(&allocated_ptys_lock);
}
@@ -558,11 +605,15 @@ void devpts_pty_kill(struct tty_struct *tty)
static int __init init_devpts_fs(void)
{
int err = register_filesystem(&devpts_fs_type);
struct ctl_table_header *table;
if (!err) {
table = register_sysctl_table(pty_root_table);
devpts_mnt = kern_mount(&devpts_fs_type);
if (IS_ERR(devpts_mnt)) {
err = PTR_ERR(devpts_mnt);
unregister_filesystem(&devpts_fs_type);
unregister_sysctl_table(table);
}
}
return err;