From e673927d8a210ab1db27047080fc1bdb47f7e372 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Mon, 4 Jun 2012 13:35:20 +0200 Subject: [PATCH] TTY: ircomm, revamp locking Use self->spinlock only for ctrl_skb and tx_skb. TTY stuff is now protected by tty_port->lock. This is needed for further cleanup (and conversion to tty_port helpers). This also closes the race in the end of close. Signed-off-by: Jiri Slaby Cc: Samuel Ortiz Cc: netdev@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- include/net/irda/ircomm_tty.h | 1 - net/irda/ircomm/ircomm_tty.c | 38 +++++++++++++++++------------------ 2 files changed, 18 insertions(+), 21 deletions(-) diff --git a/include/net/irda/ircomm_tty.h b/include/net/irda/ircomm_tty.h index e4db3b5f6e4c..a9027d8f670d 100644 --- a/include/net/irda/ircomm_tty.h +++ b/include/net/irda/ircomm_tty.h @@ -96,7 +96,6 @@ struct ircomm_tty_cb { struct work_struct tqueue; /* Protect concurent access to : - * o self->open_count * o self->ctrl_skb * o self->tx_skb * Maybe other things may gain to be protected as well... diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c index 8e61026b9dd4..7b2152cfd42a 100644 --- a/net/irda/ircomm/ircomm_tty.c +++ b/net/irda/ircomm/ircomm_tty.c @@ -283,13 +283,12 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self, IRDA_DEBUG(2, "%s(%d):block_til_ready before block on %s open_count=%d\n", __FILE__, __LINE__, tty->driver->name, self->port.count); - /* As far as I can see, we protect port.count - Jean II */ - spin_lock_irqsave(&self->spinlock, flags); + spin_lock_irqsave(&self->port.lock, flags); if (!tty_hung_up_p(filp)) { extra_count = 1; self->port.count--; } - spin_unlock_irqrestore(&self->spinlock, flags); + spin_unlock_irqrestore(&self->port.lock, flags); self->port.blocked_open++; while (1) { @@ -340,9 +339,9 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self, if (extra_count) { /* ++ is not atomic, so this should be protected - Jean II */ - spin_lock_irqsave(&self->spinlock, flags); + spin_lock_irqsave(&self->port.lock, flags); self->port.count++; - spin_unlock_irqrestore(&self->spinlock, flags); + spin_unlock_irqrestore(&self->port.lock, flags); } self->port.blocked_open--; @@ -409,12 +408,12 @@ static int ircomm_tty_open(struct tty_struct *tty, struct file *filp) hashbin_insert(ircomm_tty, (irda_queue_t *) self, line, NULL); } /* ++ is not atomic, so this should be protected - Jean II */ - spin_lock_irqsave(&self->spinlock, flags); + spin_lock_irqsave(&self->port.lock, flags); self->port.count++; tty->driver_data = self; self->tty = tty; - spin_unlock_irqrestore(&self->spinlock, flags); + spin_unlock_irqrestore(&self->port.lock, flags); IRDA_DEBUG(1, "%s(), %s%d, count = %d\n", __func__ , tty->driver->name, self->line, self->port.count); @@ -495,10 +494,10 @@ static void ircomm_tty_close(struct tty_struct *tty, struct file *filp) IRDA_ASSERT(self != NULL, return;); IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;); - spin_lock_irqsave(&self->spinlock, flags); + spin_lock_irqsave(&self->port.lock, flags); if (tty_hung_up_p(filp)) { - spin_unlock_irqrestore(&self->spinlock, flags); + spin_unlock_irqrestore(&self->port.lock, flags); IRDA_DEBUG(0, "%s(), returning 1\n", __func__ ); return; @@ -524,20 +523,15 @@ static void ircomm_tty_close(struct tty_struct *tty, struct file *filp) self->port.count = 0; } if (self->port.count) { - spin_unlock_irqrestore(&self->spinlock, flags); + spin_unlock_irqrestore(&self->port.lock, flags); IRDA_DEBUG(0, "%s(), open count > 0\n", __func__ ); return; } - /* Hum... Should be test_and_set_bit ??? - Jean II */ set_bit(ASYNCB_CLOSING, &self->port.flags); - /* We need to unlock here (we were unlocking at the end of this - * function), because tty_wait_until_sent() may schedule. - * I don't know if the rest should be protected somehow, - * so someone should check. - Jean II */ - spin_unlock_irqrestore(&self->spinlock, flags); + spin_unlock_irqrestore(&self->port.lock, flags); /* * Now we wait for the transmit buffer to clear; and we notify @@ -552,16 +546,21 @@ static void ircomm_tty_close(struct tty_struct *tty, struct file *filp) tty_driver_flush_buffer(tty); tty_ldisc_flush(tty); + spin_lock_irqsave(&self->port.lock, flags); tty->closing = 0; self->tty = NULL; if (self->port.blocked_open) { - if (self->port.close_delay) + if (self->port.close_delay) { + spin_unlock_irqrestore(&self->port.lock, flags); schedule_timeout_interruptible(self->port.close_delay); + spin_lock_irqsave(&self->port.lock, flags); + } wake_up_interruptible(&self->port.open_wait); } self->port.flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING); + spin_unlock_irqrestore(&self->port.lock, flags); wake_up_interruptible(&self->port.close_wait); } @@ -1003,12 +1002,11 @@ static void ircomm_tty_hangup(struct tty_struct *tty) /* ircomm_tty_flush_buffer(tty); */ ircomm_tty_shutdown(self); - /* I guess we need to lock here - Jean II */ - spin_lock_irqsave(&self->spinlock, flags); + spin_lock_irqsave(&self->port.lock, flags); self->port.flags &= ~ASYNC_NORMAL_ACTIVE; self->tty = NULL; self->port.count = 0; - spin_unlock_irqrestore(&self->spinlock, flags); + spin_unlock_irqrestore(&self->port.lock, flags); wake_up_interruptible(&self->port.open_wait); }