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Message-Id: <1160742994.19143.386.camel@amol.verismonetworks.com>
Date: Fri, 13 Oct 2006 18:06:34 +0530
From: Amol Lad <amol@...ismonetworks.com>
To: Arjan van de Ven <arjan@...radead.org>
Cc: linux kernel <linux-kernel@...r.kernel.org>,
kernel Janitors <kernel-janitors@...ts.osdl.org>
Subject: Re: [PATCH] drivers/char/riscom8.c: save_flags()/cli()/sti()
removal
Removed save_flags()/cli()/sti() and used (light weight ) spin lock.
Signed-off-by: Amol Lad <amol@...ismonetworks.com>
---
> I applaud removing such legacy-should-be-dead-by-now functions; however,
> I'm not entirely sure your conversion is correct. While you convert all
> places that do cli/sti with locks.... you do not seem to be adding the
> locks to the places that the cli/sti pairs protected against (the IRQ
> handlers).... so it looks like your conversion is incomplete ;(
It's added. I'm not able to fine-grain the lock in the interrupt
handler. After reading the code a bit I thought it's not safe for me to
fine-grain it.
---
--- linux-2.6.19-rc1-orig/drivers/char/riscom8.c 2006-10-05 14:00:43.000000000 +0530
+++ linux-2.6.19-rc1/drivers/char/riscom8.c 2006-10-13 17:58:57.000000000 +0530
@@ -81,6 +81,7 @@
static struct riscom_board * IRQ_to_board[16];
static struct tty_driver *riscom_driver;
+spinlock_t riscom_lock = SPIN_LOCK_UNLOCKED;
static unsigned long baud_table[] = {
0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
@@ -231,13 +232,13 @@ 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_irq(&riscom_lock);
rc_long_delay(HZ/20); /* Delay 0.05 sec */
- cli();
+ spin_lock_irq(&riscom_lock);
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 */
@@ -248,7 +249,7 @@ 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. */
@@ -557,13 +558,15 @@ static irqreturn_t rc_interrupt(int irq,
struct riscom_board *bp;
unsigned long loop = 0;
int handled = 0;
+ unsigned long flags;
bp = IRQ_to_board[irq];
if (!bp || !(bp->flags & RC_BOARD_ACTIVE)) {
return IRQ_NONE;
}
-
+
+ spin_lock_irqsave(&riscom_lock, flags);
while ((++loop < 16) && ((status = ~(rc_in(bp, RC_BSR))) &
(RC_BSR_TOUT | RC_BSR_TINT |
RC_BSR_MINT | RC_BSR_RINT))) {
@@ -609,6 +612,7 @@ static irqreturn_t rc_interrupt(int irq,
rc_out(bp, CD180_EOIR, 0); /* Mark end of interrupt */
rc_out(bp, RC_CTOUT, 0); /* Clear timeout flag */
}
+ spin_unlock_irqrestore(&riscom_lock, flags);
return IRQ_RETVAL(handled);
}
@@ -832,7 +836,7 @@ 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);
@@ -844,7 +848,7 @@ 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;
}
@@ -955,19 +959,19 @@ static int block_til_ready(struct tty_st
*/
retval = 0;
add_wait_queue(&port->open_wait, &wait);
- cli();
+ spin_lock_irq(&riscom_lock);
if (!tty_hung_up_p(filp))
port->count--;
- sti();
+ spin_unlock_irq(&riscom_lock);
port->blocked_open++;
while (1) {
- cli();
+ spin_lock_irq(&riscom_lock);
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_irq(&riscom_lock);
set_current_state(TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) ||
!(port->flags & ASYNC_INITIALIZED)) {
@@ -1040,7 +1044,7 @@ 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;
@@ -1107,7 +1111,8 @@ 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,
@@ -1126,34 +1131,34 @@ static int rc_write(struct tty_struct *
if (!tty || !port->xmit_buf)
return 0;
- save_flags(flags);
+ local_save_flags(flags);
while (1) {
- cli();
+ spin_lock_irq(&riscom_lock);
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);
+ spin_unlock_irqrestore(&riscom_lock, flags);
break;
}
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();
+ spin_lock_irq(&riscom_lock);
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;
}
@@ -1169,7 +1174,7 @@ 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;
@@ -1177,7 +1182,8 @@ 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)
@@ -1192,11 +1198,11 @@ 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)
@@ -1231,9 +1237,9 @@ 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);
wake_up_interruptible(&tty->write_wait);
tty_wakeup(tty);
@@ -1251,11 +1257,11 @@ 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)
@@ -1276,7 +1282,7 @@ 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)
@@ -1290,7 +1296,7 @@ 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;
}
@@ -1299,7 +1305,7 @@ 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;
@@ -1309,7 +1315,7 @@ 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,
@@ -1352,9 +1358,9 @@ static inline int rc_set_serial_info(str
port->closing_wait = tmp.closing_wait;
}
if (change_speed) {
- save_flags(flags); cli();
+ spin_lock_irqsave(&riscom_lock, flags);
rc_change_speed(bp, port);
- restore_flags(flags);
+ spin_unlock_irqrestore(&riscom_lock, flags);
}
return 0;
}
@@ -1435,7 +1441,7 @@ static void rc_throttle(struct tty_struc
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)) {
@@ -1444,7 +1450,7 @@ static void rc_throttle(struct tty_struc
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)
@@ -1458,7 +1464,7 @@ 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)) {
@@ -1467,7 +1473,7 @@ 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)
@@ -1481,11 +1487,11 @@ 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)
@@ -1499,13 +1505,13 @@ 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);
}
/*
@@ -1557,9 +1563,9 @@ 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)) {
@@ -1648,11 +1654,10 @@ 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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