From: Jeff Garzik 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. Signed-off-by: Jeff Garzik Signed-off-by: Andrew Morton --- drivers/char/Kconfig | 2 drivers/char/riscom8.c | 147 ++++++++++++++++++++++++--------------- 2 files changed, 94 insertions(+), 55 deletions(-) diff -puN drivers/char/Kconfig~riscom8-fix-smp-brokenness drivers/char/Kconfig --- a/drivers/char/Kconfig~riscom8-fix-smp-brokenness +++ a/drivers/char/Kconfig @@ -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 diff -puN drivers/char/riscom8.c~riscom8-fix-smp-brokenness drivers/char/riscom8.c --- a/drivers/char/riscom8.c~riscom8-fix-smp-brokenness +++ a/drivers/char/riscom8.c @@ -47,6 +47,7 @@ #include #include #include +#include #include @@ -81,6 +82,8 @@ static struct tty_driver *riscom_driver; +static spinlock_t riscom_lock = SPIN_LOCK_UNLOCKED; + static struct riscom_board rc_board[RC_NBOARD] = { { .base = RC_IOBASE1, @@ -217,13 +220,14 @@ static void __init rc_init_CD180(struct { 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 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 @@ static int rc_setup_port(struct riscom_b } 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_b 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_st 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_st */ 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 @@ static void rc_close(struct tty_struct * 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 * } 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 * 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_struc 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_struc 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_st !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_s 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 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 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 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 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 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(str 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(str 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 @@ static void rc_throttle(struct tty_struc 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 @@ static void rc_unthrottle(struct tty_str 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_str 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 * 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 * 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_st 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 _