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riscom8: fix SMP brokenness

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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>
This commit is contained in:
Jeff Garzik 2008-02-06 01:36:11 -08:00 committed by Linus Torvalds
parent 1c17d18e37
commit d9afa43532
2 changed files with 94 additions and 55 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/char/Kconfig
View File

@ -276,7 +276,7 @@ config N_HDLC
config RISCOM8
tristate "SDL RISCom/8 card support"
depends on SERIAL_NONSTANDARD && BROKEN_ON_SMP
depends on SERIAL_NONSTANDARD
help
This is a driver for the SDL Communications RISCom/8 multiport card,
which gives you many serial ports. You would need something like

137
drivers/char/riscom8.c
View File

@ -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 @@ static void __init rc_init_CD180(struct riscom_board const * bp)
{
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 @@ static void __init rc_init_CD180(struct riscom_board const * bp)
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. */
@ -813,7 +817,7 @@ static int rc_setup_port(struct riscom_board *bp, struct riscom_port *port)
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 @@ static int rc_setup_port(struct riscom_board *bp, struct riscom_port *port)
rc_change_speed(bp, port);
port->flags |= ASYNC_INITIALIZED;
restore_flags(flags);
spin_unlock_irqrestore(&riscom_lock, flags);
return 0;
}
@ -901,6 +905,7 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
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 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
*/
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)) {
@ -1021,7 +1033,8 @@ static void rc_close(struct tty_struct * tty, struct file * filp)
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 @@ static void rc_close(struct tty_struct * tty, struct file * filp)
}
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 @@ static int rc_write(struct tty_struct * tty,
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 @@ static void rc_put_char(struct tty_struct * tty, unsigned char ch)
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 @@ static void rc_put_char(struct tty_struct * tty, unsigned char ch)
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 @@ static void rc_flush_chars(struct tty_struct * tty)
!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 @@ static void rc_flush_buffer(struct tty_struct *tty)
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 @@ static int rc_tiocmget(struct tty_struct *tty, struct file *file)
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 @@ static int rc_tiocmset(struct tty_struct *tty, struct file *file,
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 @@ static int rc_tiocmset(struct tty_struct *tty, struct file *file,
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 @@ static inline void rc_send_break(struct riscom_port * port, unsigned long length
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 @@ static inline void rc_send_break(struct riscom_port * port, unsigned long length
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 @@ static inline int rc_set_serial_info(struct riscom_port * port,
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 @@ static inline int rc_set_serial_info(struct riscom_port * port,
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;
}
@ -1415,7 +1445,8 @@ static void rc_throttle(struct tty_struct * tty)
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)) {
@ -1424,7 +1455,8 @@ static void rc_throttle(struct tty_struct * tty)
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 @@ static void rc_unthrottle(struct tty_struct * tty)
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 @@ static void rc_unthrottle(struct tty_struct * tty)
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 @@ static void rc_stop(struct tty_struct * tty)
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 @@ static void rc_start(struct tty_struct * tty)
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 @@ static void rc_set_termios(struct tty_struct * tty, struct ktermios * old_termio
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 @@ static void rc_release_drivers(void)
{
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