| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <1202411485-16022-4-git-send-email-jirislaby@gmail.com>
Date: Thu, 7 Feb 2008 20:11:20 +0100
From: Jiri Slaby <jirislaby@...il.com>
To: "Oyvind Aabling" <Oyvind.Aabling@...-c.dk>
Cc: <linux-kernel@...r.kernel.org>, Jiri Slaby <jirislaby@...il.com>
Subject: [RFT 4/9] Char: moxa, rework open/close
- add locking to open/close/hangup
- add pci hot-un-plug support (hangup on board remove, wait for openers)
- cleanup block_till_ready
- move close code common to close/hangup into separate function to be
able to call it from open when hangup occurs while block_till_ready
- let ldisc flush on tty layer, it will do it after we return
Signed-off-by: Jiri Slaby <jirislaby@...il.com>
---
drivers/char/moxa.c | 239 +++++++++++++++++++++------------------------------
1 files changed, 97 insertions(+), 142 deletions(-)
diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index eabb2e0..5a55b8c 100644
--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -42,7 +42,6 @@
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/bitops.h>
-#include <linux/completion.h>
#include <asm/system.h>
#include <asm/io.h>
@@ -134,13 +133,11 @@ struct moxa_port {
int type;
int close_delay;
- int count;
- int blocked_open;
+ unsigned int count;
int asyncflags;
int cflag;
unsigned long statusflags;
wait_queue_head_t open_wait;
- struct completion close_wait;
u8 DCDState;
u8 lineCtrl;
@@ -167,6 +164,7 @@ static int ttymajor = MOXAMAJOR;
static struct mon_str moxaLog;
static unsigned int moxaFuncTout = HZ / 2;
static unsigned int moxaLowWaterChk;
+static DEFINE_MUTEX(moxa_openlock);
/* Variables for insmod */
#ifdef MODULE
static unsigned long baseaddr[MAX_BOARDS];
@@ -209,8 +207,6 @@ static int moxa_tiocmset(struct tty_struct *tty, struct file *file,
unsigned int set, unsigned int clear);
static void moxa_poll(unsigned long);
static void moxa_set_tty_param(struct tty_struct *, struct ktermios *);
-static int moxa_block_till_ready(struct tty_struct *, struct file *,
- struct moxa_port *);
static void moxa_setup_empty_event(struct tty_struct *);
static void moxa_shut_down(struct moxa_port *);
/*
@@ -817,7 +813,6 @@ static int moxa_init_board(struct moxa_board_conf *brd, struct device *dev)
p->close_delay = 5 * HZ / 10;
p->cflag = B9600 | CS8 | CREAD | CLOCAL | HUPCL;
init_waitqueue_head(&p->open_wait);
- init_completion(&p->close_wait);
}
switch (brd->boardType) {
@@ -861,9 +856,30 @@ err:
static void moxa_board_deinit(struct moxa_board_conf *brd)
{
+ unsigned int a, opened;
+
+ mutex_lock(&moxa_openlock);
spin_lock_bh(&moxa_lock);
brd->ready = 0;
spin_unlock_bh(&moxa_lock);
+
+ /* pci hot-un-plug support */
+ for (a = 0; a < brd->numPorts; a++)
+ if (brd->ports[a].asyncflags & ASYNC_NORMAL_ACTIVE)
+ tty_hangup(brd->ports[a].tty);
+ while (1) {
+ opened = 0;
+ for (a = 0; a < brd->numPorts; a++)
+ if (brd->ports[a].asyncflags & ASYNC_NORMAL_ACTIVE)
+ opened++;
+ mutex_unlock(&moxa_openlock);
+ if (!opened)
+ break;
+ set_task_state(current, TASK_UNINTERRUPTIBLE);
+ schedule_timeout(msecs_to_jiffies(50));
+ mutex_lock(&moxa_openlock);
+ }
+
iounmap(brd->basemem);
brd->basemem = NULL;
kfree(brd->ports);
@@ -1060,6 +1076,44 @@ static void __exit moxa_exit(void)
module_init(moxa_init);
module_exit(moxa_exit);
+static void moxa_close_port(struct moxa_port *ch)
+{
+ moxa_shut_down(ch);
+ MoxaPortFlushData(ch, 2);
+ ch->asyncflags &= ~ASYNC_NORMAL_ACTIVE;
+ ch->tty = NULL;
+}
+
+static int moxa_block_till_ready(struct tty_struct *tty, struct file *filp,
+ struct moxa_port *ch)
+{
+ DEFINE_WAIT(wait);
+ int retval = 0;
+
+ while (1) {
+ prepare_to_wait(&ch->open_wait, &wait, TASK_INTERRUPTIBLE);
+ if (tty_hung_up_p(filp)) {
+#ifdef SERIAL_DO_RESTART
+ retval = -ERESTARTSYS;
+#else
+ retval = -EAGAIN;
+#endif
+ break;
+ }
+ if (ch->DCDState)
+ break;
+
+ if (signal_pending(current)) {
+ retval = -ERESTARTSYS;
+ break;
+ }
+ schedule();
+ }
+ finish_wait(&ch->open_wait, &wait);
+
+ return retval;
+}
+
static int moxa_open(struct tty_struct *tty, struct file *filp)
{
struct moxa_board_conf *brd;
@@ -1071,9 +1125,13 @@ static int moxa_open(struct tty_struct *tty, struct file *filp)
if (port == MAX_PORTS) {
return capable(CAP_SYS_ADMIN) ? 0 : -EPERM;
}
+ if (mutex_lock_interruptible(&moxa_openlock))
+ return -ERESTARTSYS;
brd = &moxa_boards[port / MAX_PORTS_PER_BOARD];
- if (!brd->ready)
+ if (!brd->ready) {
+ mutex_unlock(&moxa_openlock);
return -ENODEV;
+ }
ch = &brd->ports[port % MAX_PORTS_PER_BOARD];
ch->count++;
@@ -1084,39 +1142,37 @@ static int moxa_open(struct tty_struct *tty, struct file *filp)
moxa_set_tty_param(tty, tty->termios);
MoxaPortLineCtrl(ch, 1, 1);
MoxaPortEnable(ch);
+ MoxaSetFifo(ch, ch->type == PORT_16550A);
ch->asyncflags |= ASYNC_INITIALIZED;
}
- retval = moxa_block_till_ready(tty, filp, ch);
-
- moxa_unthrottle(tty);
+ mutex_unlock(&moxa_openlock);
- if (ch->type == PORT_16550A) {
- MoxaSetFifo(ch, 1);
- } else {
- MoxaSetFifo(ch, 0);
- }
+ retval = 0;
+ if (!(filp->f_flags & O_NONBLOCK) && !C_CLOCAL(tty))
+ retval = moxa_block_till_ready(tty, filp, ch);
+ mutex_lock(&moxa_openlock);
+ if (retval) {
+ if (ch->count) /* 0 means already hung up... */
+ if (--ch->count == 0)
+ moxa_close_port(ch);
+ } else
+ ch->asyncflags |= ASYNC_NORMAL_ACTIVE;
+ mutex_unlock(&moxa_openlock);
- return (retval);
+ return retval;
}
static void moxa_close(struct tty_struct *tty, struct file *filp)
{
- struct moxa_port *ch;
+ struct moxa_port *ch = tty->driver_data;
int port;
port = tty->index;
- if (port == MAX_PORTS) {
- return;
- }
- if (tty->driver_data == NULL) {
+ if (port == MAX_PORTS || ch == NULL || tty_hung_up_p(filp))
return;
- }
- if (tty_hung_up_p(filp)) {
- return;
- }
- ch = (struct moxa_port *) tty->driver_data;
- if ((tty->count == 1) && (ch->count != 1)) {
+ mutex_lock(&moxa_openlock);
+ if (tty->count == 1 && ch->count != 1) {
printk(KERN_WARNING "moxa_close: bad serial port count; "
"tty->count is 1, ch->count is %d\n", ch->count);
ch->count = 1;
@@ -1127,32 +1183,18 @@ static void moxa_close(struct tty_struct *tty, struct file *filp)
ch->count = 0;
}
if (ch->count) {
+ mutex_unlock(&moxa_openlock);
return;
}
- ch->asyncflags |= ASYNC_CLOSING;
ch->cflag = tty->termios->c_cflag;
if (ch->asyncflags & ASYNC_INITIALIZED) {
moxa_setup_empty_event(tty);
tty_wait_until_sent(tty, 30 * HZ); /* 30 seconds timeout */
}
- moxa_shut_down(ch);
- MoxaPortFlushData(ch, 2);
- if (tty->driver->flush_buffer)
- tty->driver->flush_buffer(tty);
- tty_ldisc_flush(tty);
-
- tty->closing = 0;
- ch->tty = NULL;
- if (ch->blocked_open) {
- if (ch->close_delay) {
- msleep_interruptible(jiffies_to_msecs(ch->close_delay));
- }
- wake_up_interruptible(&ch->open_wait);
- }
- ch->asyncflags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING);
- complete_all(&ch->close_wait);
+ moxa_close_port(ch);
+ mutex_unlock(&moxa_openlock);
}
static int moxa_write(struct tty_struct *tty,
@@ -1347,13 +1389,13 @@ static void moxa_start(struct tty_struct *tty)
static void moxa_hangup(struct tty_struct *tty)
{
- struct moxa_port *ch = (struct moxa_port *) tty->driver_data;
+ struct moxa_port *ch = tty->driver_data;
- moxa_flush_buffer(tty);
- moxa_shut_down(ch);
+ mutex_lock(&moxa_openlock);
ch->count = 0;
- ch->asyncflags &= ~ASYNC_NORMAL_ACTIVE;
- ch->tty = NULL;
+ moxa_close_port(ch);
+ mutex_unlock(&moxa_openlock);
+
wake_up_interruptible(&ch->open_wait);
}
@@ -1362,10 +1404,8 @@ static void moxa_new_dcdstate(struct moxa_port *p, u8 dcd)
dcd = !!dcd;
if ((dcd != p->DCDState) && p->tty && C_CLOCAL(p->tty)) {
- if (!dcd) {
+ if (!dcd)
tty_hangup(p->tty);
- p->asyncflags &= ~ASYNC_NORMAL_ACTIVE;
- }
wake_up_interruptible(&p->open_wait);
}
p->DCDState = dcd;
@@ -1499,91 +1539,6 @@ static void moxa_set_tty_param(struct tty_struct *tty, struct ktermios *old_term
tty_encode_baud_rate(tty, baud, baud);
}
-static int moxa_block_till_ready(struct tty_struct *tty, struct file *filp,
- struct moxa_port *ch)
-{
- DECLARE_WAITQUEUE(wait,current);
- int retval;
- int do_clocal = C_CLOCAL(tty);
-
- /*
- * If the device is in the middle of being closed, then block
- * until it's done, and then try again.
- */
- if (tty_hung_up_p(filp) || (ch->asyncflags & ASYNC_CLOSING)) {
- if (ch->asyncflags & ASYNC_CLOSING)
- wait_for_completion_interruptible(&ch->close_wait);
-#ifdef SERIAL_DO_RESTART
- if (ch->asyncflags & ASYNC_HUP_NOTIFY)
- return (-EAGAIN);
- else
- return (-ERESTARTSYS);
-#else
- return (-EAGAIN);
-#endif
- }
- /*
- * If non-blocking mode is set, then make the check up front
- * and then exit.
- */
- if (filp->f_flags & O_NONBLOCK) {
- ch->asyncflags |= ASYNC_NORMAL_ACTIVE;
- return (0);
- }
- /*
- * Block waiting for the carrier detect and the line to become free
- */
- retval = 0;
- add_wait_queue(&ch->open_wait, &wait);
- pr_debug("block_til_ready before block: ttys%d, count = %d\n",
- tty->index, ch->count);
- spin_lock_bh(&moxa_lock);
- if (!tty_hung_up_p(filp))
- ch->count--;
- ch->blocked_open++;
- spin_unlock_bh(&moxa_lock);
-
- while (1) {
- set_current_state(TASK_INTERRUPTIBLE);
- if (tty_hung_up_p(filp) ||
- !(ch->asyncflags & ASYNC_INITIALIZED)) {
-#ifdef SERIAL_DO_RESTART
- if (ch->asyncflags & ASYNC_HUP_NOTIFY)
- retval = -EAGAIN;
- else
- retval = -ERESTARTSYS;
-#else
- retval = -EAGAIN;
-#endif
- break;
- }
- if (!(ch->asyncflags & ASYNC_CLOSING) && (do_clocal ||
- ch->DCDState))
- break;
-
- if (signal_pending(current)) {
- retval = -ERESTARTSYS;
- break;
- }
- schedule();
- }
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&ch->open_wait, &wait);
-
- spin_lock_bh(&moxa_lock);
- if (!tty_hung_up_p(filp))
- ch->count++;
- ch->blocked_open--;
- spin_unlock_bh(&moxa_lock);
- pr_debug("block_til_ready after blocking: ttys%d, count = %d\n",
- tty->index, ch->count);
- if (retval)
- return (retval);
- /* FIXME: review to see if we need to use set_bit on these */
- ch->asyncflags |= ASYNC_NORMAL_ACTIVE;
- return 0;
-}
-
static void moxa_setup_empty_event(struct tty_struct *tty)
{
struct moxa_port *ch = tty->driver_data;
@@ -1595,22 +1550,22 @@ static void moxa_setup_empty_event(struct tty_struct *tty)
static void moxa_shut_down(struct moxa_port *ch)
{
- struct tty_struct *tp;
+ struct tty_struct *tp = ch->tty;
if (!(ch->asyncflags & ASYNC_INITIALIZED))
return;
- tp = ch->tty;
-
MoxaPortDisable(ch);
/*
* If we're a modem control device and HUPCL is on, drop RTS & DTR.
*/
- if (tp->termios->c_cflag & HUPCL)
+ if (C_HUPCL(tp))
MoxaPortLineCtrl(ch, 0, 0);
+ spin_lock_bh(&moxa_lock);
ch->asyncflags &= ~ASYNC_INITIALIZED;
+ spin_unlock_bh(&moxa_lock);
}
/*****************************************************************************
--
1.5.3.8
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists