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authorEric W. Biederman <ebiederm@xmission.com>2007-05-08 00:26:53 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:04 -0700
commit2a65f1d9fe78475720bd8f0e0fbbf1973b1b5ac2 (patch)
treef23bfe8a3602d1fea448d3416c639957bccc9677
parentf67c3627b4abd8a3cf56bd20cafde702feffe236 (diff)
downloadlinux-2a65f1d9fe78475720bd8f0e0fbbf1973b1b5ac2.tar.bz2
tty: simplify calling of put_pid.
This patch should contain no functional changes. At some point I got confused and thought put_pid could not be called while a spin lock was held. While it may be nice to avoid that to reduce lock hold times put_pid can be safely called while we hold a spin lock. This patch removes all of the complications from the code introduced by my misunderstanding, making the code a little more readable. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/char/tty_io.c23
1 files changed, 6 insertions, 17 deletions
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index a7b915516d7b..39db186d5c5b 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -153,8 +153,7 @@ int tty_ioctl(struct inode * inode, struct file * file,
unsigned int cmd, unsigned long arg);
static int tty_fasync(int fd, struct file * filp, int on);
static void release_tty(struct tty_struct *tty, int idx);
-static struct pid *__proc_set_tty(struct task_struct *tsk,
- struct tty_struct *tty);
+static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty);
/**
* alloc_tty_struct - allocate a tty object
@@ -1532,10 +1531,9 @@ void disassociate_ctty(int on_exit)
}
spin_lock_irq(&current->sighand->siglock);
- tty_pgrp = current->signal->tty_old_pgrp;
+ put_pid(current->signal->tty_old_pgrp);
current->signal->tty_old_pgrp = NULL;
spin_unlock_irq(&current->sighand->siglock);
- put_pid(tty_pgrp);
mutex_lock(&tty_mutex);
/* It is possible that do_tty_hangup has free'd this tty */
@@ -2506,7 +2504,6 @@ static int tty_open(struct inode * inode, struct file * filp)
int index;
dev_t device = inode->i_rdev;
unsigned short saved_flags = filp->f_flags;
- struct pid *old_pgrp;
nonseekable_open(inode, filp);
@@ -2600,17 +2597,15 @@ got_driver:
goto retry_open;
}
- old_pgrp = NULL;
mutex_lock(&tty_mutex);
spin_lock_irq(&current->sighand->siglock);
if (!noctty &&
current->signal->leader &&
!current->signal->tty &&
tty->session == NULL)
- old_pgrp = __proc_set_tty(current, tty);
+ __proc_set_tty(current, tty);
spin_unlock_irq(&current->sighand->siglock);
mutex_unlock(&tty_mutex);
- put_pid(old_pgrp);
return 0;
}
@@ -3835,9 +3830,8 @@ void proc_clear_tty(struct task_struct *p)
spin_unlock_irq(&p->sighand->siglock);
}
-static struct pid *__proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
+static void __proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
{
- struct pid *old_pgrp;
if (tty) {
/* We should not have a session or pgrp to here but.... */
put_pid(tty->session);
@@ -3845,21 +3839,16 @@ static struct pid *__proc_set_tty(struct task_struct *tsk, struct tty_struct *tt
tty->session = get_pid(task_session(tsk));
tty->pgrp = get_pid(task_pgrp(tsk));
}
- old_pgrp = tsk->signal->tty_old_pgrp;
+ put_pid(tsk->signal->tty_old_pgrp);
tsk->signal->tty = tty;
tsk->signal->tty_old_pgrp = NULL;
- return old_pgrp;
}
void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
{
- struct pid *old_pgrp;
-
spin_lock_irq(&tsk->sighand->siglock);
- old_pgrp = __proc_set_tty(tsk, tty);
+ __proc_set_tty(tsk, tty);
spin_unlock_irq(&tsk->sighand->siglock);
-
- put_pid(old_pgrp);
}
struct tty_struct *get_current_tty(void)