Messages in this thread Patch in this message | | | From | Jeff Garzik <> | Subject | [PATCH 4/12] riscom8: fix SMP brokenness | Date | Tue, 23 Oct 2007 18:36:38 -0400 (EDT) |
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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.
Signed-off-by: Jeff Garzik <jgarzik@redhat.com> ---
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 6549110..27ab43e 100644 --- a/drivers/char/Kconfig +++ b/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 --git a/drivers/char/riscom8.c b/drivers/char/riscom8.c index b37e626..45d109c 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> @@ -82,6 +83,8 @@ static struct riscom_board * IRQ_to_board[16]; 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, @@ -218,13 +221,14 @@ 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 */ @@ -235,7 +239,7 @@ 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. */ @@ -817,9 +821,9 @@ 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); @@ -830,7 +834,7 @@ 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; } @@ -906,6 +910,7 @@ 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 @@ -941,19 +946,26 @@ 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)) { @@ -1025,8 +1037,9 @@ 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; @@ -1093,7 +1106,9 @@ 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, @@ -1112,34 +1127,33 @@ 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; } @@ -1155,7 +1169,7 @@ 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; @@ -1163,7 +1177,9 @@ 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) @@ -1178,11 +1194,13 @@ 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) @@ -1217,9 +1235,11 @@ 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); } @@ -1236,11 +1256,15 @@ 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) @@ -1261,7 +1285,8 @@ 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) @@ -1275,7 +1300,9 @@ 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; } @@ -1284,7 +1311,8 @@ 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; @@ -1294,7 +1322,8 @@ 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, @@ -1303,7 +1332,6 @@ 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; @@ -1337,9 +1365,11 @@ 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; } @@ -1419,17 +1449,19 @@ static void rc_throttle(struct tty_struct * tty) 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) @@ -1443,7 +1475,8 @@ 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)) { @@ -1452,7 +1485,8 @@ 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) @@ -1466,11 +1500,13 @@ 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) @@ -1484,13 +1520,15 @@ 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); } /* @@ -1542,9 +1580,9 @@ 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)) { @@ -1633,11 +1671,12 @@ 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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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