From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754485Ab2DBL4u (ORCPT ); Mon, 2 Apr 2012 07:56:50 -0400 Received: from mail.pripojeni.net ([178.22.112.14]:48204 "EHLO smtp.pripojeni.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752876Ab2DBLzS (ORCPT ); Mon, 2 Apr 2012 07:55:18 -0400 From: Jiri Slaby To: gregkh@linuxfoundation.org Cc: alan@linux.intel.com, linux-kernel@vger.kernel.org, jirislaby@gmail.com, Mike Frysinger , uclinux-dist-devel@blackfin.uclinux.org Subject: [PATCH 36/69] TTY: bfin_jtag_comm, use tty from tty_port Date: Mon, 2 Apr 2012 13:54:20 +0200 Message-Id: <1333367693-3244-37-git-send-email-jslaby@suse.cz> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1333367693-3244-1-git-send-email-jslaby@suse.cz> References: <1333367693-3244-1-git-send-email-jslaby@suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Switch from mutex to tty_port->lock and to tty refcounting. This needs a 'continue' to be added to re-grab a tty after schedule returns. And since tty is not protected by bfin_jc_tty_mutex remove it as well. But this needs tty_port->count to be protected by tty_port->lock now. Signed-off-by: Jiri Slaby Cc: Mike Frysinger Cc: uclinux-dist-devel@blackfin.uclinux.org --- drivers/tty/bfin_jtag_comm.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/drivers/tty/bfin_jtag_comm.c b/drivers/tty/bfin_jtag_comm.c index d81013c..61fc74f 100644 --- a/drivers/tty/bfin_jtag_comm.c +++ b/drivers/tty/bfin_jtag_comm.c @@ -62,8 +62,6 @@ static inline uint32_t bfin_write_emudat_chars(char a, char b, char c, char d) static struct tty_driver *bfin_jc_driver; static struct task_struct *bfin_jc_kthread; -static struct tty_struct * volatile bfin_jc_tty; -static DEFINE_MUTEX(bfin_jc_tty_mutex); static struct tty_port port; static volatile struct circ_buf bfin_jc_write_buf; @@ -73,18 +71,21 @@ bfin_jc_emudat_manager(void *arg) uint32_t inbound_len = 0, outbound_len = 0; while (!kthread_should_stop()) { + struct tty_struct *tty = tty_port_tty_get(&port); /* no one left to give data to, so sleep */ - if (bfin_jc_tty == NULL && circ_empty(&bfin_jc_write_buf)) { + if (tty == NULL && circ_empty(&bfin_jc_write_buf)) { pr_debug("waiting for readers\n"); __set_current_state(TASK_UNINTERRUPTIBLE); schedule(); __set_current_state(TASK_RUNNING); + continue; } /* no data available, so just chill */ if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) { pr_debug("waiting for data (in_len = %i) (circ: %i %i)\n", inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head); + tty_kref_put(tty); if (inbound_len) schedule(); else @@ -94,9 +95,6 @@ bfin_jc_emudat_manager(void *arg) /* if incoming data is ready, eat it */ if (bfin_read_DBGSTAT() & EMUDIF) { - struct tty_struct *tty; - mutex_lock(&bfin_jc_tty_mutex); - tty = (struct tty_struct *)bfin_jc_tty; if (tty != NULL) { uint32_t emudat = bfin_read_emudat(); if (inbound_len == 0) { @@ -110,7 +108,6 @@ bfin_jc_emudat_manager(void *arg) tty_flip_buffer_push(tty); } } - mutex_unlock(&bfin_jc_tty_mutex); } /* if outgoing data is ready, post it */ @@ -120,7 +117,6 @@ bfin_jc_emudat_manager(void *arg) bfin_write_emudat(outbound_len); pr_debug("outgoing length: 0x%08x\n", outbound_len); } else { - struct tty_struct *tty; int tail = bfin_jc_write_buf.tail; size_t ate = (4 <= outbound_len ? 4 : outbound_len); uint32_t emudat = @@ -132,14 +128,12 @@ bfin_jc_emudat_manager(void *arg) ); bfin_jc_write_buf.tail += ate; outbound_len -= ate; - mutex_lock(&bfin_jc_tty_mutex); - tty = (struct tty_struct *)bfin_jc_tty; if (tty) tty_wakeup(tty); - mutex_unlock(&bfin_jc_tty_mutex); pr_debug(" outgoing data: 0x%08x (pushing %zu)\n", emudat, ate); } } + tty_kref_put(tty); } __set_current_state(TASK_RUNNING); @@ -149,22 +143,28 @@ bfin_jc_emudat_manager(void *arg) static int bfin_jc_open(struct tty_struct *tty, struct file *filp) { - mutex_lock(&bfin_jc_tty_mutex); + unsigned long flags; + + spin_lock_irqsave(&port.lock, flags); port.count++; - bfin_jc_tty = tty; + spin_unlock_irqrestore(&port.lock, flags); + tty_port_tty_set(&port, tty); wake_up_process(bfin_jc_kthread); - mutex_unlock(&bfin_jc_tty_mutex); return 0; } static void bfin_jc_close(struct tty_struct *tty, struct file *filp) { - mutex_lock(&bfin_jc_tty_mutex); - if (--port.count == 0) - bfin_jc_tty = NULL; + unsigned long flags; + bool last; + + spin_lock_irqsave(&port.lock, flags); + last = --port.count == 0; + spin_unlock_irqrestore(&port.lock, flags); + if (last) + tty_port_tty_set(&port, NULL); wake_up_process(bfin_jc_kthread); - mutex_unlock(&bfin_jc_tty_mutex); } /* XXX: we dont handle the put_char() case where we must handle count = 1 */ -- 1.7.9.2