tty: r3964: Use tty->read_wait waitqueue

The tty core provides read_wait waitqueue specifically for line
disciplines to wait readers; otherwise, the line discipline may
miss wakeups generated by the tty core.

NB: The tty core already provides serialization for the line discipline's
close() method, and guarantees no readers or writers will be using the
closing instance of the line discipline. Completely remove that wakeup.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/n_r3964.c b/drivers/tty/n_r3964.c
index 8b157d68a03e97aa2089d9b3c4d98fdb0b109719..6fdef921cdb77fafefd2b9d5b9671747531ce0a4 100644 (file)
--- a/drivers/tty/n_r3964.c
+++ b/drivers/tty/n_r3964.c
@@ -276,7 +276,7 @@ static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
                        add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
                                error_code, NULL);
                }
-               wake_up_interruptible(&pInfo->read_wait);
+               wake_up_interruptible(&pInfo->tty->read_wait);
        }
 
        spin_lock_irqsave(&pInfo->lock, flags);
@@ -542,7 +542,7 @@ static void on_receive_block(struct r3964_info *pInfo)
                                pBlock);
                }
        }
-       wake_up_interruptible(&pInfo->read_wait);
+       wake_up_interruptible(&pInfo->tty->read_wait);
 
        pInfo->state = R3964_IDLE;
 
@@ -979,7 +979,6 @@ static int r3964_open(struct tty_struct *tty)
 
        spin_lock_init(&pInfo->lock);
        pInfo->tty = tty;
-       init_waitqueue_head(&pInfo->read_wait);
        pInfo->priority = R3964_MASTER;
        pInfo->rx_first = pInfo->rx_last = NULL;
        pInfo->tx_first = pInfo->tx_last = NULL;
@@ -1045,7 +1044,6 @@ static void r3964_close(struct tty_struct *tty)
        }
 
        /* Free buffers: */
-       wake_up_interruptible(&pInfo->read_wait);
        kfree(pInfo->rx_buf);
        TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
        kfree(pInfo->tx_buf);
@@ -1077,7 +1075,7 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
                                goto unlock;
                        }
                        /* block until there is a message: */
-                       wait_event_interruptible_tty(tty, pInfo->read_wait,
+                       wait_event_interruptible_tty(tty, tty->read_wait,
                                        (pMsg = remove_msg(pInfo, pClient)));
                }
 
@@ -1227,7 +1225,7 @@ static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
 
        pClient = findClient(pInfo, task_pid(current));
        if (pClient) {
-               poll_wait(file, &pInfo->read_wait, wait);
+               poll_wait(file, &tty->read_wait, wait);
                spin_lock_irqsave(&pInfo->lock, flags);
                pMsg = pClient->first_msg;
                spin_unlock_irqrestore(&pInfo->lock, flags);

diff --git a/include/linux/n_r3964.h b/include/linux/n_r3964.h
index 5d0b2a1dee69c9814fe218407aa3bf381d577e23..e9adb4226224cd638e4abd3eaf6529b3c6425baa 100644 (file)
--- a/include/linux/n_r3964.h
+++ b/include/linux/n_r3964.h
@@ -152,9 +152,6 @@ struct r3964_info {
        unsigned char *rx_buf;            /* ring buffer */
        unsigned char *tx_buf;
 
-       wait_queue_head_t read_wait;
-       //struct wait_queue *read_wait;
-
        struct r3964_block_header *rx_first;
        struct r3964_block_header *rx_last;
        struct r3964_block_header *tx_first;