Char: mxser, fix TIOCMIWAIT

There was schedule() missing in the TIOCMIWAIT ioctl. Solve it by moving
the code to the wait_event_interruptible.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Jan Yenya Kasprzak <kas@fi.muni.cz>
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>

1 files changed, 14 insertions, 34 deletions

diff --git a/drivers/char/mxser.c b/drivers/char/mxser.c
index a61fb6da5d03..80a01150b86c 100644
--- a/drivers/char/mxser.c
+++ b/drivers/char/mxser.c
@@ -1338,43 +1338,23 @@ static int mxser_ioctl(struct tty_struct *tty, struct file *file, unsigned int c
                  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
                  * Caller should use TIOCGICOUNT to see which one it was
                  */
-        case TIOCMIWAIT: {
-                        DECLARE_WAITQUEUE(wait, current);
-                        int ret;
+        case TIOCMIWAIT:
+                spin_lock_irqsave(&info->slock, flags);
+                cnow = info->icount;    /* note the counters on entry */
+                spin_unlock_irqrestore(&info->slock, flags);
+
+                wait_event_interruptible(info->delta_msr_wait, ({
+                        cprev = cnow;
                         spin_lock_irqsave(&info->slock, flags);
-                        cprev = info->icount;   /* note the counters on entry */
+                        cnow = info->icount;    /* atomic copy */
                         spin_unlock_irqrestore(&info->slock, flags);
 
-                        add_wait_queue(&info->delta_msr_wait, &wait);
-                        while (1) {
-                                spin_lock_irqsave(&info->slock, flags);
-                                cnow = info->icount;    /* atomic copy */
-                                spin_unlock_irqrestore(&info->slock, flags);
-
-                                set_current_state(TASK_INTERRUPTIBLE);
-                                if (((arg & TIOCM_RNG) &&
-                                                (cnow.rng != cprev.rng)) ||
-                                                ((arg & TIOCM_DSR) &&
-                                                (cnow.dsr != cprev.dsr)) ||
-                                                ((arg & TIOCM_CD) &&
-                                                (cnow.dcd != cprev.dcd)) ||
-                                                ((arg & TIOCM_CTS) &&
-                                                (cnow.cts != cprev.cts))) {
-                                        ret = 0;
-                                        break;
-                                }
-                                /* see if a signal did it */
-                                if (signal_pending(current)) {
-                                        ret = -ERESTARTSYS;
-                                        break;
-                                }
-                                cprev = cnow;
-                        }
-                        current->state = TASK_RUNNING;
-                        remove_wait_queue(&info->delta_msr_wait, &wait);
-                        break;
-                }
-                /* NOTREACHED */
+                        ((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
+                        ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
+                        ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
+                        ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts));
+                }));
+                break;
                 /*
                  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
                  * Return: write counters to the user passed counter struct