tty: kref usage for isicom and moxa
Rather than blindly keep taking krefs we reorder the code in a few places
to pass the tty down to the right place (which is important as from the user
side it is not the case that tty == port->tty in all situations). For the irq
and related paths use the krefs to stop the tty being freed under us.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index d3d7864e..5df4003 100644
--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -205,7 +205,7 @@
static void moxa_poll(unsigned long);
static void moxa_set_tty_param(struct tty_struct *, struct ktermios *);
static void moxa_setup_empty_event(struct tty_struct *);
-static void moxa_shut_down(struct moxa_port *);
+static void moxa_shut_down(struct tty_struct *);
/*
* moxa board interface functions:
*/
@@ -217,7 +217,7 @@
static void MoxaPortFlowCtrl(struct moxa_port *, int, int, int, int, int);
static int MoxaPortLineStatus(struct moxa_port *);
static void MoxaPortFlushData(struct moxa_port *, int);
-static int MoxaPortWriteData(struct moxa_port *, const unsigned char *, int);
+static int MoxaPortWriteData(struct tty_struct *, const unsigned char *, int);
static int MoxaPortReadData(struct moxa_port *);
static int MoxaPortTxQueue(struct moxa_port *);
static int MoxaPortRxQueue(struct moxa_port *);
@@ -332,6 +332,7 @@
for (i = 0; i < MAX_BOARDS; i++) {
p = moxa_boards[i].ports;
for (j = 0; j < MAX_PORTS_PER_BOARD; j++, p++, argm++) {
+ struct tty_struct *ttyp;
memset(&tmp, 0, sizeof(tmp));
if (!moxa_boards[i].ready)
goto copy;
@@ -344,10 +345,12 @@
if (status & 4)
tmp.dcd = 1;
- if (!p->port.tty || !p->port.tty->termios)
+ ttyp = tty_port_tty_get(&p->port);
+ if (!ttyp || !ttyp->termios)
tmp.cflag = p->cflag;
else
- tmp.cflag = p->port.tty->termios->c_cflag;
+ tmp.cflag = ttyp->termios->c_cflag;
+ tty_kref_put(tty);
copy:
if (copy_to_user(argm, &tmp, sizeof(tmp))) {
mutex_unlock(&moxa_openlock);
@@ -880,8 +883,14 @@
/* pci hot-un-plug support */
for (a = 0; a < brd->numPorts; a++)
- if (brd->ports[a].port.flags & ASYNC_INITIALIZED)
- tty_hangup(brd->ports[a].port.tty);
+ if (brd->ports[a].port.flags & ASYNC_INITIALIZED) {
+ struct tty_struct *tty = tty_port_tty_get(
+ &brd->ports[a].port);
+ if (tty) {
+ tty_hangup(tty);
+ tty_kref_put(tty);
+ }
+ }
while (1) {
opened = 0;
for (a = 0; a < brd->numPorts; a++)
@@ -1096,13 +1105,14 @@
module_init(moxa_init);
module_exit(moxa_exit);
-static void moxa_close_port(struct moxa_port *ch)
+static void moxa_close_port(struct tty_struct *tty)
{
- moxa_shut_down(ch);
+ struct moxa_port *ch = tty->driver_data;
+ moxa_shut_down(tty);
MoxaPortFlushData(ch, 2);
ch->port.flags &= ~ASYNC_NORMAL_ACTIVE;
- ch->port.tty->driver_data = NULL;
- ch->port.tty = NULL;
+ tty->driver_data = NULL;
+ tty_port_tty_set(&ch->port, NULL);
}
static int moxa_block_till_ready(struct tty_struct *tty, struct file *filp,
@@ -1161,7 +1171,7 @@
ch = &brd->ports[port % MAX_PORTS_PER_BOARD];
ch->port.count++;
tty->driver_data = ch;
- ch->port.tty = tty;
+ tty_port_tty_set(&ch->port, tty);
if (!(ch->port.flags & ASYNC_INITIALIZED)) {
ch->statusflags = 0;
moxa_set_tty_param(tty, tty->termios);
@@ -1179,7 +1189,7 @@
if (retval) {
if (ch->port.count) /* 0 means already hung up... */
if (--ch->port.count == 0)
- moxa_close_port(ch);
+ moxa_close_port(tty);
} else
ch->port.flags |= ASYNC_NORMAL_ACTIVE;
mutex_unlock(&moxa_openlock);
@@ -1219,7 +1229,7 @@
tty_wait_until_sent(tty, 30 * HZ); /* 30 seconds timeout */
}
- moxa_close_port(ch);
+ moxa_close_port(tty);
unlock:
mutex_unlock(&moxa_openlock);
}
@@ -1234,7 +1244,7 @@
return 0;
spin_lock_bh(&moxa_lock);
- len = MoxaPortWriteData(ch, buf, count);
+ len = MoxaPortWriteData(tty, buf, count);
spin_unlock_bh(&moxa_lock);
ch->statusflags |= LOWWAIT;
@@ -1409,7 +1419,7 @@
return;
}
ch->port.count = 0;
- moxa_close_port(ch);
+ moxa_close_port(tty);
mutex_unlock(&moxa_openlock);
wake_up_interruptible(&ch->port.open_wait);
@@ -1417,11 +1427,14 @@
static void moxa_new_dcdstate(struct moxa_port *p, u8 dcd)
{
+ struct tty_struct *tty;
dcd = !!dcd;
- if (dcd != p->DCDState && p->port.tty && C_CLOCAL(p->port.tty)) {
- if (!dcd)
- tty_hangup(p->port.tty);
+ if (dcd != p->DCDState) {
+ tty = tty_port_tty_get(&p->port);
+ if (tty && C_CLOCAL(tty) && !dcd)
+ tty_hangup(tty);
+ tty_kref_put(tty);
}
p->DCDState = dcd;
}
@@ -1429,7 +1442,7 @@
static int moxa_poll_port(struct moxa_port *p, unsigned int handle,
u16 __iomem *ip)
{
- struct tty_struct *tty = p->port.tty;
+ struct tty_struct *tty = tty_port_tty_get(&p->port);
void __iomem *ofsAddr;
unsigned int inited = p->port.flags & ASYNC_INITIALIZED;
u16 intr;
@@ -1476,6 +1489,7 @@
tty_insert_flip_char(tty, 0, TTY_BREAK);
tty_schedule_flip(tty);
}
+ tty_kref_put(tty);
if (intr & IntrLine)
moxa_new_dcdstate(p, readb(ofsAddr + FlagStat) & DCD_state);
@@ -1560,9 +1574,9 @@
spin_unlock_bh(&moxa_lock);
}
-static void moxa_shut_down(struct moxa_port *ch)
+static void moxa_shut_down(struct tty_struct *tty)
{
- struct tty_struct *tp = ch->port.tty;
+ struct moxa_port *ch = tty->driver_data;
if (!(ch->port.flags & ASYNC_INITIALIZED))
return;
@@ -1572,7 +1586,7 @@
/*
* If we're a modem control device and HUPCL is on, drop RTS & DTR.
*/
- if (C_HUPCL(tp))
+ if (C_HUPCL(tty))
MoxaPortLineCtrl(ch, 0, 0);
spin_lock_bh(&moxa_lock);
@@ -1953,9 +1967,10 @@
return val;
}
-static int MoxaPortWriteData(struct moxa_port *port,
+static int MoxaPortWriteData(struct tty_struct *tty,
const unsigned char *buffer, int len)
{
+ struct moxa_port *port = tty->driver_data;
void __iomem *baseAddr, *ofsAddr, *ofs;
unsigned int c, total;
u16 head, tail, tx_mask, spage, epage;