From: Peter Hurley <peter@hurleysoftware.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>, Alan Cox <alan@linux.intel.com>,
David Laight <David.Laight@aculab.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
netdev@vger.kernel.org, David Miller <davem@davemloft.net>,
Peter Hurley <peter@hurleysoftware.com>
Subject: [PATCH 5/7] tty: r3964: Use tty->read_wait waitqueue
Date: Sat, 10 Oct 2015 16:00:55 -0400 [thread overview]
Message-ID: <1444507257-7513-6-git-send-email-peter@hurleysoftware.com> (raw)
In-Reply-To: <1444507257-7513-1-git-send-email-peter@hurleysoftware.com>
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>
---
drivers/tty/n_r3964.c | 10 ++++------
include/linux/n_r3964.h | 3 ---
2 files changed, 4 insertions(+), 9 deletions(-)
diff --git a/drivers/tty/n_r3964.c b/drivers/tty/n_r3964.c
index 8b157d6..6fdef92 100644
--- 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 5d0b2a1..e9adb42 100644
--- 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;
--
2.6.1
next prev parent reply other threads:[~2015-10-10 20:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-10 20:00 [PATCH 0/7] tty close cleanup Peter Hurley
2015-10-10 20:00 ` [PATCH 1/7] tty: Remove tty_wait_until_sent_from_close() Peter Hurley
2015-10-10 20:00 ` [PATCH 2/7] tty: Remove ASYNC_CLOSING checks in open()/hangup() methods Peter Hurley
2015-10-18 4:13 ` Greg Kroah-Hartman
2015-10-10 20:00 ` [PATCH 3/7] usb: gadget: gserial: Privatize close_wait Peter Hurley
2015-10-10 20:09 ` Peter Hurley
2015-10-10 20:00 ` [PATCH 4/7] tty: Remove tty_port::close_wait Peter Hurley
2015-10-10 20:00 ` Peter Hurley [this message]
2015-10-10 20:00 ` [PATCH 6/7] tty: r3964: Replace/remove bogus tty lock use Peter Hurley
2015-10-10 20:00 ` [PATCH 7/7] tty: Remove wait_event_interruptible_tty() Peter Hurley
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