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* [PATCH] do_acct_process: don't take tty_mutex
@ 2006-10-23 13:56 Oleg Nesterov
  2006-10-24  9:48 ` Peter Zijlstra
  0 siblings, 1 reply; 2+ messages in thread
From: Oleg Nesterov @ 2006-10-23 13:56 UTC (permalink / raw)
  To: Andrew Morton; +Cc: Peter Zijlstra, Alan Cox, linux-kernel

Depends on
	tty-signal-tty-locking.patch

No need to take the global tty_mutex, signal->tty->driver can't go away
while we are holding ->siglock.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>

--- rc2-mm2/kernel/acct.c~	2006-10-22 19:28:17.000000000 +0400
+++ rc2-mm2/kernel/acct.c	2006-10-23 17:09:12.000000000 +0400
@@ -484,12 +484,9 @@ static void do_acct_process(struct file 
 	ac.ac_ppid = current->parent->tgid;
 #endif
 
-	mutex_lock(&tty_mutex);
-	tty = get_current_tty();
-	ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
-	mutex_unlock(&tty_mutex);
-
 	spin_lock_irq(&current->sighand->siglock);
+	tty = current->signal->tty;
+	ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
 	ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
 	ac.ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));
 	ac.ac_flag = pacct->ac_flag;


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] do_acct_process: don't take tty_mutex
  2006-10-23 13:56 [PATCH] do_acct_process: don't take tty_mutex Oleg Nesterov
@ 2006-10-24  9:48 ` Peter Zijlstra
  0 siblings, 0 replies; 2+ messages in thread
From: Peter Zijlstra @ 2006-10-24  9:48 UTC (permalink / raw)
  To: Oleg Nesterov; +Cc: Andrew Morton, Alan Cox, linux-kernel

On Mon, 2006-10-23 at 17:56 +0400, Oleg Nesterov wrote:
> Depends on
> 	tty-signal-tty-locking.patch
> 
> No need to take the global tty_mutex, signal->tty->driver can't go away
> while we are holding ->siglock.
> 
> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>

Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl

> --- rc2-mm2/kernel/acct.c~	2006-10-22 19:28:17.000000000 +0400
> +++ rc2-mm2/kernel/acct.c	2006-10-23 17:09:12.000000000 +0400
> @@ -484,12 +484,9 @@ static void do_acct_process(struct file 
>  	ac.ac_ppid = current->parent->tgid;
>  #endif
>  
> -	mutex_lock(&tty_mutex);
> -	tty = get_current_tty();
> -	ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
> -	mutex_unlock(&tty_mutex);
> -
>  	spin_lock_irq(&current->sighand->siglock);
> +	tty = current->signal->tty;
> +	ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
>  	ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
>  	ac.ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));
>  	ac.ac_flag = pacct->ac_flag;
> 


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2006-10-24  9:47 UTC | newest]

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2006-10-23 13:56 [PATCH] do_acct_process: don't take tty_mutex Oleg Nesterov
2006-10-24  9:48 ` Peter Zijlstra

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