From: Jiri Slaby <jirislaby@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-kernel@vger.kernel.org>
Cc: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Subject: [PATCH 1/3] Char: mxser_new, fix recursive locking
Date: Fri, 20 Apr 2007 12:34:41 +0200 (CEST) [thread overview]
Message-ID: <20225157853131727049@wsc.cz> (raw)
Andrew, I think it would be good to have these 3 in 2.6.21.
--
mxser_new, fix recursive locking
Acquire a port lock only if not in_interrupt in some places, because ISR
holds the lock yet (and ldisc calls some of driver's routines which tries to
acquire it again due to tty->low_latency).
Thanks to Jan "Yenya" Kasprzak.
Cc: Jan "Yenya" Kasprzak <kas@fi.muni.cz>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
---
commit a3c71212efb38a67d344f35137136808e64537c6
tree c1ec123ca7007190dfae8c06fafec4702d88e00c
parent 0156510dee9d326af2ec52cf8b1a388ce9a839e9
author Jiri Slaby <jirislaby@gmail.com> Mon, 16 Apr 2007 13:24:46 +0200
committer Jiri Slaby <jirislaby@gmail.com> Mon, 16 Apr 2007 13:24:46 +0200
drivers/char/mxser_new.c | 46 ++++++++++++++++++++++++++++------------------
1 files changed, 28 insertions(+), 18 deletions(-)
diff --git a/drivers/char/mxser_new.c b/drivers/char/mxser_new.c
index 6362e78..626f491 100644
--- a/drivers/char/mxser_new.c
+++ b/drivers/char/mxser_new.c
@@ -85,6 +85,16 @@
#define MXSER_HIGHBAUD 1
#define MXSER_HAS2 2
+/* if we are in interrupt, lock is held by ISR, don't acquire it again! */
+#define mx_lock(info, flags) do { \
+ if (!in_interrupt()) \
+ spin_lock_irqsave(&(info)->slock, flags); \
+} while (0)
+#define mx_unlock(info, flags) do { \
+ if (!in_interrupt()) \
+ spin_unlock_irqrestore(&(info)->slock, flags); \
+} while (0)
+
/* This is only for PCI */
static const struct {
int type;
@@ -869,7 +879,7 @@ static void mxser_shutdown(struct mxser_port *info)
if (!(info->flags & ASYNC_INITIALIZED))
return;
- spin_lock_irqsave(&info->slock, flags);
+ mx_lock(info, flags);
/*
* clear delta_msr_wait queue to avoid mem leaks: we may free the irq
@@ -912,7 +922,7 @@ static void mxser_shutdown(struct mxser_port *info)
if (info->board->chip_flag)
SET_MOXA_MUST_NO_SOFTWARE_FLOW_CONTROL(info->ioaddr);
- spin_unlock_irqrestore(&info->slock, flags);
+ mx_unlock(info, flags);
}
/*
@@ -1076,11 +1086,11 @@ static int mxser_write(struct tty_struct *tty, const unsigned char *buf, int cou
break;
memcpy(info->xmit_buf + info->xmit_head, buf, c);
- spin_lock_irqsave(&info->slock, flags);
+ mx_lock(info, flags);
info->xmit_head = (info->xmit_head + c) &
(SERIAL_XMIT_SIZE - 1);
info->xmit_cnt += c;
- spin_unlock_irqrestore(&info->slock, flags);
+ mx_unlock(info, flags);
buf += c;
count -= c;
@@ -1091,12 +1101,12 @@ static int mxser_write(struct tty_struct *tty, const unsigned char *buf, int cou
if (!tty->hw_stopped ||
(info->type == PORT_16550A) ||
(info->board->chip_flag)) {
- spin_lock_irqsave(&info->slock, flags);
+ mx_lock(info, flags);
outb(info->IER & ~UART_IER_THRI, info->ioaddr +
UART_IER);
info->IER |= UART_IER_THRI;
outb(info->IER, info->ioaddr + UART_IER);
- spin_unlock_irqrestore(&info->slock, flags);
+ mx_unlock(info, flags);
}
}
return total;
@@ -1113,20 +1123,20 @@ static void mxser_put_char(struct tty_struct *tty, unsigned char ch)
if (info->xmit_cnt >= SERIAL_XMIT_SIZE - 1)
return;
- spin_lock_irqsave(&info->slock, flags);
+ mx_lock(info, flags);
info->xmit_buf[info->xmit_head++] = ch;
info->xmit_head &= SERIAL_XMIT_SIZE - 1;
info->xmit_cnt++;
- spin_unlock_irqrestore(&info->slock, flags);
+ mx_unlock(info, flags);
if (!tty->stopped) {
if (!tty->hw_stopped ||
(info->type == PORT_16550A) ||
info->board->chip_flag) {
- spin_lock_irqsave(&info->slock, flags);
+ mx_lock(info, flags);
outb(info->IER & ~UART_IER_THRI, info->ioaddr + UART_IER);
info->IER |= UART_IER_THRI;
outb(info->IER, info->ioaddr + UART_IER);
- spin_unlock_irqrestore(&info->slock, flags);
+ mx_unlock(info, flags);
}
}
}
@@ -1146,13 +1156,13 @@ static void mxser_flush_chars(struct tty_struct *tty)
))
return;
- spin_lock_irqsave(&info->slock, flags);
+ mx_lock(info, flags);
outb(info->IER & ~UART_IER_THRI, info->ioaddr + UART_IER);
info->IER |= UART_IER_THRI;
outb(info->IER, info->ioaddr + UART_IER);
- spin_unlock_irqrestore(&info->slock, flags);
+ mx_unlock(info, flags);
}
static int mxser_write_room(struct tty_struct *tty)
@@ -1179,7 +1189,7 @@ static void mxser_flush_buffer(struct tty_struct *tty)
unsigned long flags;
- spin_lock_irqsave(&info->slock, flags);
+ mx_lock(info, flags);
info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
fcr = inb(info->ioaddr + UART_FCR);
@@ -1187,7 +1197,7 @@ static void mxser_flush_buffer(struct tty_struct *tty)
info->ioaddr + UART_FCR);
outb(fcr, info->ioaddr + UART_FCR);
- spin_unlock_irqrestore(&info->slock, flags);
+ mx_unlock(info, flags);
tty_wakeup(tty);
}
@@ -1983,12 +1993,12 @@ static void mxser_stop(struct tty_struct *tty)
struct mxser_port *info = tty->driver_data;
unsigned long flags;
- spin_lock_irqsave(&info->slock, flags);
+ mx_lock(info, flags);
if (info->IER & UART_IER_THRI) {
info->IER &= ~UART_IER_THRI;
outb(info->IER, info->ioaddr + UART_IER);
}
- spin_unlock_irqrestore(&info->slock, flags);
+ mx_unlock(info, flags);
}
static void mxser_start(struct tty_struct *tty)
@@ -1996,13 +2006,13 @@ static void mxser_start(struct tty_struct *tty)
struct mxser_port *info = tty->driver_data;
unsigned long flags;
- spin_lock_irqsave(&info->slock, flags);
+ mx_lock(info, flags);
if (info->xmit_cnt && info->xmit_buf) {
outb(info->IER & ~UART_IER_THRI, info->ioaddr + UART_IER);
info->IER |= UART_IER_THRI;
outb(info->IER, info->ioaddr + UART_IER);
}
- spin_unlock_irqrestore(&info->slock, flags);
+ mx_unlock(info, flags);
}
static void mxser_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
next reply other threads:[~2007-04-20 10:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-20 10:34 Jiri Slaby [this message]
2007-04-20 10:35 ` [PATCH 2/3] Char: mxser_new, fix TIOCMIWAIT Jiri Slaby
2007-04-20 14:12 ` Jan Yenya Kasprzak
2007-04-20 10:36 ` [PATCH 3/3] Char: mxser, " Jiri Slaby
2007-04-20 12:12 ` [PATCH 1/3] Char: mxser_new, fix recursive locking Alan Cox
2007-04-20 14:15 ` Jan Yenya Kasprzak
2007-04-20 14:18 ` Jiri Slaby
2007-04-20 15:29 ` Alan Cox
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20225157853131727049@wsc.cz \
--to=jirislaby@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®