From be1bc2889a4db4961ef69f47fb471ecae9f23ade Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 1 Jun 2010 22:53:05 +0200 Subject: tty: introduce wait_event_interruptible_tty Calling wait_event_interruptible implicitly releases the BKL when it sleeps, but we need to do this explcitly when we have converted it to a mutex. Signed-off-by: Arnd Bergmann Cc: Alan Cox Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/char/cyclades.c b/drivers/char/cyclades.c index 51acfe3..27aad94 100644 --- a/drivers/char/cyclades.c +++ b/drivers/char/cyclades.c @@ -1607,7 +1607,7 @@ static int cy_open(struct tty_struct *tty, struct file *filp) * If the port is the middle of closing, bail out now */ if (tty_hung_up_p(filp) || (info->port.flags & ASYNC_CLOSING)) { - wait_event_interruptible(info->port.close_wait, + wait_event_interruptible_tty(info->port.close_wait, !(info->port.flags & ASYNC_CLOSING)); return (info->port.flags & ASYNC_HUP_NOTIFY) ? -EAGAIN: -ERESTARTSYS; } diff --git a/drivers/char/istallion.c b/drivers/char/istallion.c index 5e9a81d..be28391 100644 --- a/drivers/char/istallion.c +++ b/drivers/char/istallion.c @@ -954,7 +954,7 @@ static int stli_rawopen(struct stlibrd *brdp, struct stliport *portp, unsigned l * order of opens and closes may not be preserved across shared * memory, so we must wait until it is complete. */ - wait_event_interruptible(portp->raw_wait, + wait_event_interruptible_tty(portp->raw_wait, !test_bit(ST_CLOSING, &portp->state)); if (signal_pending(current)) { return -ERESTARTSYS; @@ -989,7 +989,7 @@ static int stli_rawopen(struct stlibrd *brdp, struct stliport *portp, unsigned l set_bit(ST_OPENING, &portp->state); spin_unlock_irqrestore(&brd_lock, flags); - wait_event_interruptible(portp->raw_wait, + wait_event_interruptible_tty(portp->raw_wait, !test_bit(ST_OPENING, &portp->state)); if (signal_pending(current)) rc = -ERESTARTSYS; @@ -1020,7 +1020,7 @@ static int stli_rawclose(struct stlibrd *brdp, struct stliport *portp, unsigned * occurs on this port. */ if (wait) { - wait_event_interruptible(portp->raw_wait, + wait_event_interruptible_tty(portp->raw_wait, !test_bit(ST_CLOSING, &portp->state)); if (signal_pending(current)) { return -ERESTARTSYS; @@ -1052,7 +1052,7 @@ static int stli_rawclose(struct stlibrd *brdp, struct stliport *portp, unsigned * to come back. */ rc = 0; - wait_event_interruptible(portp->raw_wait, + wait_event_interruptible_tty(portp->raw_wait, !test_bit(ST_CLOSING, &portp->state)); if (signal_pending(current)) rc = -ERESTARTSYS; @@ -1073,6 +1073,10 @@ static int stli_rawclose(struct stlibrd *brdp, struct stliport *portp, unsigned static int stli_cmdwait(struct stlibrd *brdp, struct stliport *portp, unsigned long cmd, void *arg, int size, int copyback) { + /* + * no need for wait_event_tty because clearing ST_CMDING cannot block + * on BTM + */ wait_event_interruptible(portp->raw_wait, !test_bit(ST_CMDING, &portp->state)); if (signal_pending(current)) diff --git a/drivers/char/n_r3964.c b/drivers/char/n_r3964.c index f4bd259..a98290d 100644 --- a/drivers/char/n_r3964.c +++ b/drivers/char/n_r3964.c @@ -1079,7 +1079,7 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file, goto unlock; } /* block until there is a message: */ - wait_event_interruptible(pInfo->read_wait, + wait_event_interruptible_tty(pInfo->read_wait, (pMsg = remove_msg(pInfo, pClient))); } diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c index a3bd1d0..35eb3040 100644 --- a/drivers/char/tty_port.c +++ b/drivers/char/tty_port.c @@ -231,7 +231,7 @@ int tty_port_block_til_ready(struct tty_port *port, /* block if port is in the process of being closed */ if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) { - wait_event_interruptible(port->close_wait, + wait_event_interruptible_tty(port->close_wait, !(port->flags & ASYNC_CLOSING)); if (port->flags & ASYNC_HUP_NOTIFY) return -EAGAIN; diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c index cf87c53..2bbeaae 100644 --- a/drivers/char/vt_ioctl.c +++ b/drivers/char/vt_ioctl.c @@ -133,7 +133,7 @@ static void vt_event_wait(struct vt_event_wait *vw) list_add(&vw->list, &vt_events); spin_unlock_irqrestore(&vt_event_lock, flags); /* Wait for it to pass */ - wait_event_interruptible(vt_event_waitqueue, vw->done); + wait_event_interruptible_tty(vt_event_waitqueue, vw->done); /* Dequeue it */ spin_lock_irqsave(&vt_event_lock, flags); list_del(&vw->list); @@ -1761,10 +1761,13 @@ int vt_move_to_console(unsigned int vt, int alloc) return -EIO; } release_console_sem(); + tty_lock(); if (vt_waitactive(vt + 1)) { pr_debug("Suspend: Can't switch VCs."); + tty_unlock(); return -EINTR; } + tty_unlock(); return prev; } diff --git a/drivers/serial/crisv10.c b/drivers/serial/crisv10.c index f848e18..94bfb9f 100644 --- a/drivers/serial/crisv10.c +++ b/drivers/serial/crisv10.c @@ -3992,7 +3992,7 @@ block_til_ready(struct tty_struct *tty, struct file * filp, */ if (tty_hung_up_p(filp) || (info->flags & ASYNC_CLOSING)) { - wait_event_interruptible(info->close_wait, + wait_event_interruptible_tty(info->close_wait, !(info->flags & ASYNC_CLOSING)); #ifdef SERIAL_DO_RESTART if (info->flags & ASYNC_HUP_NOTIFY) @@ -4150,7 +4150,7 @@ rs_open(struct tty_struct *tty, struct file * filp) */ if (tty_hung_up_p(filp) || (info->flags & ASYNC_CLOSING)) { - wait_event_interruptible(info->close_wait, + wait_event_interruptible_tty(info->close_wait, !(info->flags & ASYNC_CLOSING)); #ifdef SERIAL_DO_RESTART return ((info->flags & ASYNC_HUP_NOTIFY) ? diff --git a/include/linux/tty.h b/include/linux/tty.h index 6ead6b6..955d72e 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -607,5 +607,47 @@ static inline void tty_unlock(void) __releases(kernel_lock) } #define tty_locked() (kernel_locked()) +/* + * wait_event_interruptible_tty -- wait for a condition with the tty lock held + * + * The condition we are waiting for might take a long time to + * become true, or might depend on another thread taking the + * BTM. In either case, we need to drop the BTM to guarantee + * forward progress. This is a leftover from the conversion + * from the BKL and should eventually get removed as the BTM + * falls out of use. + * + * Do not use in new code. + */ +#define wait_event_interruptible_tty(wq, condition) \ +({ \ + int __ret = 0; \ + if (!(condition)) { \ + __wait_event_interruptible_tty(wq, condition, __ret); \ + } \ + __ret; \ +}) + +#define __wait_event_interruptible_tty(wq, condition, ret) \ +do { \ + DEFINE_WAIT(__wait); \ + \ + for (;;) { \ + prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \ + if (condition) \ + break; \ + if (!signal_pending(current)) { \ + tty_unlock(); \ + schedule(); \ + tty_lock(); \ + continue; \ + } \ + ret = -ERESTARTSYS; \ + break; \ + } \ + finish_wait(&wq, &__wait); \ +} while (0) + + #endif /* __KERNEL__ */ #endif -- cgit v0.10.2