Commit d9afa435 authored by Jeff Garzik's avatar Jeff Garzik Committed by Linus Torvalds
Browse files

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: default avatarJeff Garzik <jgarzik@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1c17d18e

drivers/char/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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

drivers/char/riscom8.c

+93 −54
Original line number Diff line number Diff line
@@ -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

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