riscom8: fix SMP brokenness
After analyzing the elements that save_flags/cli/sti/restore_flags were
protecting, convert their usages to a global spinlock (the easiest and
most obvious next-step). There were some usages of flags being
intentionally cached, because the code already knew the state of
interrupts. These have been taken into account.
This allows us to remove CONFIG_BROKEN_ON_SMP. Completely untested.
[akpm@linux-foundation.org: use DEFINE_SPINLOCK]
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/riscom8.c b/drivers/char/riscom8.c
index 102ece4..d130b87 100644
--- a/drivers/char/riscom8.c
+++ b/drivers/char/riscom8.c
@@ -47,6 +47,7 @@
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/tty_flip.h>
+#include <linux/spinlock.h>
#include <asm/uaccess.h>
@@ -81,6 +82,8 @@
static struct tty_driver *riscom_driver;
+static DEFINE_SPINLOCK(riscom_lock);
+
static struct riscom_board rc_board[RC_NBOARD] = {
{
.base = RC_IOBASE1,
@@ -217,13 +220,14 @@
{
unsigned long flags;
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
rc_out(bp, RC_CTOUT, 0); /* Clear timeout */
rc_wait_CCR(bp); /* Wait for CCR ready */
rc_out(bp, CD180_CCR, CCR_HARDRESET); /* Reset CD180 chip */
- sti();
+ spin_unlock_irqrestore(&riscom_lock, flags);
msleep(50); /* Delay 0.05 sec */
- cli();
+ spin_lock_irqsave(&riscom_lock, flags);
rc_out(bp, CD180_GIVR, RC_ID); /* Set ID for this chip */
rc_out(bp, CD180_GICR, 0); /* Clear all bits */
rc_out(bp, CD180_PILR1, RC_ACK_MINT); /* Prio for modem intr */
@@ -234,7 +238,7 @@
rc_out(bp, CD180_PPRH, (RC_OSCFREQ/(1000000/RISCOM_TPS)) >> 8);
rc_out(bp, CD180_PPRL, (RC_OSCFREQ/(1000000/RISCOM_TPS)) & 0xff);
- restore_flags(flags);
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
/* Main probing routine, also sets irq. */
@@ -812,9 +816,9 @@
}
port->xmit_buf = (unsigned char *) tmp;
}
-
- save_flags(flags); cli();
-
+
+ spin_lock_irqsave(&riscom_lock, flags);
+
if (port->tty)
clear_bit(TTY_IO_ERROR, &port->tty->flags);
@@ -825,7 +829,7 @@
rc_change_speed(bp, port);
port->flags |= ASYNC_INITIALIZED;
- restore_flags(flags);
+ spin_unlock_irqrestore(&riscom_lock, flags);
return 0;
}
@@ -901,6 +905,7 @@
int retval;
int do_clocal = 0;
int CD;
+ unsigned long flags;
/*
* If the device is in the middle of being closed, then block
@@ -936,19 +941,26 @@
*/
retval = 0;
add_wait_queue(&port->open_wait, &wait);
- cli();
+
+ spin_lock_irqsave(&riscom_lock, flags);
+
if (!tty_hung_up_p(filp))
port->count--;
- sti();
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
+
port->blocked_open++;
while (1) {
- cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
rc_out(bp, CD180_CAR, port_No(port));
CD = rc_in(bp, CD180_MSVR) & MSVR_CD;
rc_out(bp, CD180_MSVR, MSVR_RTS);
bp->DTR &= ~(1u << port_No(port));
rc_out(bp, RC_DTR, bp->DTR);
- sti();
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
+
set_current_state(TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) ||
!(port->flags & ASYNC_INITIALIZED)) {
@@ -1020,8 +1032,9 @@
if (!port || rc_paranoia_check(port, tty->name, "close"))
return;
-
- save_flags(flags); cli();
+
+ spin_lock_irqsave(&riscom_lock, flags);
+
if (tty_hung_up_p(filp))
goto out;
@@ -1088,7 +1101,9 @@
}
port->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING);
wake_up_interruptible(&port->close_wait);
-out: restore_flags(flags);
+
+out:
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
static int rc_write(struct tty_struct * tty,
@@ -1107,34 +1122,33 @@
if (!tty || !port->xmit_buf)
return 0;
- save_flags(flags);
while (1) {
- cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
c = min_t(int, count, min(SERIAL_XMIT_SIZE - port->xmit_cnt - 1,
SERIAL_XMIT_SIZE - port->xmit_head));
- if (c <= 0) {
- restore_flags(flags);
- break;
- }
+ if (c <= 0)
+ break; /* lock continues to be held */
memcpy(port->xmit_buf + port->xmit_head, buf, c);
port->xmit_head = (port->xmit_head + c) & (SERIAL_XMIT_SIZE-1);
port->xmit_cnt += c;
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
buf += c;
count -= c;
total += c;
}
- cli();
if (port->xmit_cnt && !tty->stopped && !tty->hw_stopped &&
!(port->IER & IER_TXRDY)) {
port->IER |= IER_TXRDY;
rc_out(bp, CD180_CAR, port_No(port));
rc_out(bp, CD180_IER, port->IER);
}
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
return total;
}
@@ -1150,7 +1164,7 @@
if (!tty || !port->xmit_buf)
return;
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
if (port->xmit_cnt >= SERIAL_XMIT_SIZE - 1)
goto out;
@@ -1158,7 +1172,9 @@
port->xmit_buf[port->xmit_head++] = ch;
port->xmit_head &= SERIAL_XMIT_SIZE - 1;
port->xmit_cnt++;
-out: restore_flags(flags);
+
+out:
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
static void rc_flush_chars(struct tty_struct * tty)
@@ -1173,11 +1189,13 @@
!port->xmit_buf)
return;
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
port->IER |= IER_TXRDY;
rc_out(port_Board(port), CD180_CAR, port_No(port));
rc_out(port_Board(port), CD180_IER, port->IER);
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
static int rc_write_room(struct tty_struct * tty)
@@ -1212,9 +1230,11 @@
if (rc_paranoia_check(port, tty->name, "rc_flush_buffer"))
return;
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
tty_wakeup(tty);
}
@@ -1231,11 +1251,15 @@
return -ENODEV;
bp = port_Board(port);
- save_flags(flags); cli();
+
+ spin_lock_irqsave(&riscom_lock, flags);
+
rc_out(bp, CD180_CAR, port_No(port));
status = rc_in(bp, CD180_MSVR);
result = rc_in(bp, RC_RI) & (1u << port_No(port)) ? 0 : TIOCM_RNG;
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
+
result |= ((status & MSVR_RTS) ? TIOCM_RTS : 0)
| ((status & MSVR_DTR) ? TIOCM_DTR : 0)
| ((status & MSVR_CD) ? TIOCM_CAR : 0)
@@ -1256,7 +1280,8 @@
bp = port_Board(port);
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
if (set & TIOCM_RTS)
port->MSVR |= MSVR_RTS;
if (set & TIOCM_DTR)
@@ -1270,7 +1295,9 @@
rc_out(bp, CD180_CAR, port_No(port));
rc_out(bp, CD180_MSVR, port->MSVR);
rc_out(bp, RC_DTR, bp->DTR);
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
+
return 0;
}
@@ -1279,7 +1306,8 @@
struct riscom_board *bp = port_Board(port);
unsigned long flags;
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
port->break_length = RISCOM_TPS / HZ * length;
port->COR2 |= COR2_ETC;
port->IER |= IER_TXRDY;
@@ -1289,7 +1317,8 @@
rc_wait_CCR(bp);
rc_out(bp, CD180_CCR, CCR_CORCHG2);
rc_wait_CCR(bp);
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
static inline int rc_set_serial_info(struct riscom_port * port,
@@ -1298,7 +1327,6 @@
struct serial_struct tmp;
struct riscom_board *bp = port_Board(port);
int change_speed;
- unsigned long flags;
if (copy_from_user(&tmp, newinfo, sizeof(tmp)))
return -EFAULT;
@@ -1332,9 +1360,11 @@
port->closing_wait = tmp.closing_wait;
}
if (change_speed) {
- save_flags(flags); cli();
+ unsigned long flags;
+
+ spin_lock_irqsave(&riscom_lock, flags);
rc_change_speed(bp, port);
- restore_flags(flags);
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
return 0;
}
@@ -1414,17 +1444,19 @@
return;
bp = port_Board(port);
-
- save_flags(flags); cli();
+
+ spin_lock_irqsave(&riscom_lock, flags);
+
port->MSVR &= ~MSVR_RTS;
rc_out(bp, CD180_CAR, port_No(port));
- if (I_IXOFF(tty)) {
+ if (I_IXOFF(tty)) {
rc_wait_CCR(bp);
rc_out(bp, CD180_CCR, CCR_SSCH2);
rc_wait_CCR(bp);
}
rc_out(bp, CD180_MSVR, port->MSVR);
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
static void rc_unthrottle(struct tty_struct * tty)
@@ -1438,7 +1470,8 @@
bp = port_Board(port);
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
port->MSVR |= MSVR_RTS;
rc_out(bp, CD180_CAR, port_No(port));
if (I_IXOFF(tty)) {
@@ -1447,7 +1480,8 @@
rc_wait_CCR(bp);
}
rc_out(bp, CD180_MSVR, port->MSVR);
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
static void rc_stop(struct tty_struct * tty)
@@ -1461,11 +1495,13 @@
bp = port_Board(port);
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
port->IER &= ~IER_TXRDY;
rc_out(bp, CD180_CAR, port_No(port));
rc_out(bp, CD180_IER, port->IER);
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
static void rc_start(struct tty_struct * tty)
@@ -1479,13 +1515,15 @@
bp = port_Board(port);
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
if (port->xmit_cnt && port->xmit_buf && !(port->IER & IER_TXRDY)) {
port->IER |= IER_TXRDY;
rc_out(bp, CD180_CAR, port_No(port));
rc_out(bp, CD180_IER, port->IER);
}
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
/*
@@ -1537,9 +1575,9 @@
tty->termios->c_iflag == old_termios->c_iflag)
return;
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
rc_change_speed(port_Board(port), port);
- restore_flags(flags);
+ spin_unlock_irqrestore(&riscom_lock, flags);
if ((old_termios->c_cflag & CRTSCTS) &&
!(tty->termios->c_cflag & CRTSCTS)) {
@@ -1627,11 +1665,12 @@
{
unsigned long flags;
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&riscom_lock, flags);
+
tty_unregister_driver(riscom_driver);
put_tty_driver(riscom_driver);
- restore_flags(flags);
+
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
#ifndef MODULE