[PATCH] esp: Make driver SMP-correct

From: James Nelson (james4765_at_verizon.net)
Date: 12/31/04

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To: kernel-janitors@lists.osdl.org, linux-kernel@vger.kernel.org
Date:	Thu, 30 Dec 2004 19:43:44 -0600

This is an attempt to make the esp serial driver SMP-correct. It also removes
some cruft left over from the serial_write() conversion.

Diffstat output:
drivers/char/Kconfig | 2
drivers/char/esp.c | 299 ++++++++++++++++++++++++-----------------------
include/linux/hayesesp.h | 1
3 files changed, 160 insertions(+), 142 deletions(-)

Signed-off-by: James Nelson <james4765@gmail.com>

diff -urN --exclude='*~' linux-2.6.10-original/drivers/char/esp.c linux-2.6.10/drivers/char/esp.c
--- linux-2.6.10-original/drivers/char/esp.c 2004-12-24 16:33:48.000000000 -0500
+++ linux-2.6.10/drivers/char/esp.c 2004-12-30 20:33:46.243770922 -0500
@@ -152,18 +152,6 @@
/* Standard COM flags (except for COM4, because of the 8514 problem) */
#define STD_COM_FLAGS (ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST)

-/*
- * tmp_buf is used as a temporary buffer by serial_write. We need to
- * lock it in case the memcpy_fromfs blocks while swapping in a page,
- * and some other program tries to do a serial write at the same time.
- * Since the lock will only come under contention when the system is
- * swapping and available memory is low, it makes sense to share one
- * buffer across all the serial ports, since it significantly saves
- * memory if large numbers of serial ports are open.
- */
-static unsigned char *tmp_buf;
-static DECLARE_MUTEX(tmp_buf_sem);
-
static inline int serial_paranoia_check(struct esp_struct *info,
                                         char *name, const char *routine)
{
@@ -209,34 +197,38 @@
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
         unsigned long flags;

- if (serial_paranoia_check(info, tty->name, "rs_stop"))
- return;
+ spin_lock_irqsave(&info->irq_lock, flags);
+
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
+ goto out;

- save_flags(flags); cli();
         if (info->IER & UART_IER_THRI) {
                 info->IER &= ~UART_IER_THRI;
                 serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
                 serial_out(info, UART_ESI_CMD2, info->IER);
         }

- restore_flags(flags);
+out:
+ spin_unlock_irqrestore(&info->irq_lock, flags);
}

static void rs_start(struct tty_struct *tty)
{
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
         unsigned long flags;
-
- if (serial_paranoia_check(info, tty->name, "rs_start"))
- return;
-
- save_flags(flags); cli();
+
+ spin_lock_irqsave(&info->irq_lock, flags);
+
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
+ goto out;
+
         if (info->xmit_cnt && info->xmit_buf && !(info->IER & UART_IER_THRI)) {
                 info->IER |= UART_IER_THRI;
                 serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
                 serial_out(info, UART_ESI_CMD2, info->IER);
         }
- restore_flags(flags);
+out:
+ spin_unlock_irqrestore(&info->irq_lock, flags);
}

/*
@@ -311,7 +303,7 @@
                 return;
         }

- sti();
+ spin_unlock_irq(&info->irq_lock);

         status_mask = (info->read_status_mask >> 2) & 0x07;

@@ -329,7 +321,7 @@
                         (serial_in(info, UART_ESI_RWS) >> 3) & status_mask;
         }

- cli();
+ spin_lock_irq(&info->irq_lock);

         /* make sure everything is still ok since interrupts were enabled */
         tty = info->tty;
@@ -478,7 +470,7 @@
                 info->xmit_tail = (info->xmit_tail + space_avail) &
                         (ESP_XMIT_SIZE - 1);

- sti();
+ spin_unlock_irq(&info->irq_lock);

                 for (i = 0; i < space_avail - 1; i += 2) {
                         outw(*((unsigned short *)(pio_buf->data + i)),
@@ -489,7 +481,7 @@
                         serial_out(info, UART_ESI_TX,
                                    pio_buf->data[space_avail - 1]);

- cli();
+ spin_lock_irq(&info->irq_lock);

                 if (info->xmit_cnt) {
                         serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
@@ -654,10 +646,10 @@
         err_status = 0;
         scratch = serial_in(info, UART_ESI_SID);

- cli();
+ spin_lock_irq(&info->irq_lock);

         if (!info->tty) {
- sti();
+ spin_unlock_irq(&info->irq_lock);
                 return IRQ_NONE;
         }

@@ -740,7 +732,7 @@
#ifdef SERIAL_DEBUG_INTR
         printk("end.\n");
#endif
- sti();
+ spin_unlock_irq(&info->irq_lock);
         return IRQ_HANDLED;
}

@@ -859,7 +851,7 @@
         int retval=0;
         unsigned int num_chars;

- save_flags(flags); cli();
+ spin_lock_irqsave(&info->irq_lock, flags);

         if (info->flags & ASYNC_INITIALIZED)
                 goto out;
@@ -973,7 +965,7 @@

         info->flags |= ASYNC_INITIALIZED;
         retval = 0;
-out: restore_flags(flags);
+out: spin_unlock_irqrestore(&info->irq_lock, flags);
         return retval;
}

@@ -993,7 +985,7 @@
                info->irq);
#endif

- save_flags(flags); cli(); /* Disable interrupts */
+ spin_lock_irqsave(&info->irq_lock, flags); /* Disable interrupts */

         /*
          * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
@@ -1058,7 +1050,7 @@
                 set_bit(TTY_IO_ERROR, &info->tty->flags);

         info->flags &= ~ASYNC_INITIALIZED;
- restore_flags(flags);
+ spin_unlock_irqrestore(&info->irq_lock, flags);
}

/*
@@ -1172,7 +1164,7 @@
         if (I_IXOFF(info->tty))
                 flow1 |= 0x81;

- save_flags(flags); cli();
+ spin_lock_irqsave(&info->irq_lock, flags);
         /* set baud */
         serial_out(info, UART_ESI_CMD1, ESI_SET_BAUD);
         serial_out(info, UART_ESI_CMD2, quot >> 8);
@@ -1219,7 +1211,7 @@
         serial_out(info, UART_ESI_CMD2, info->config.flow_on >> 8);
         serial_out(info, UART_ESI_CMD2, info->config.flow_on);

- restore_flags(flags);
+ spin_unlock_irqrestore(&info->irq_lock, flags);
}

static void rs_put_char(struct tty_struct *tty, unsigned char ch)
@@ -1227,42 +1219,44 @@
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
         unsigned long flags;

- if (serial_paranoia_check(info, tty->name, "rs_put_char"))
- return;
+ spin_lock_irqsave(&info->irq_lock, flags);
+
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
+ goto out;

         if (!tty || !info->xmit_buf)
- return;
+ goto out;

- save_flags(flags); cli();
- if (info->xmit_cnt >= ESP_XMIT_SIZE - 1) {
- restore_flags(flags);
- return;
- }
+ if (info->xmit_cnt >= ESP_XMIT_SIZE - 1)
+ goto out;

         info->xmit_buf[info->xmit_head++] = ch;
         info->xmit_head &= ESP_XMIT_SIZE-1;
         info->xmit_cnt++;
- restore_flags(flags);
+out:
+ spin_unlock_irqrestore(&info->irq_lock, flags);
}

static void rs_flush_chars(struct tty_struct *tty)
{
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
         unsigned long flags;
-
- if (serial_paranoia_check(info, tty->name, "rs_flush_chars"))
- return;
+
+ spin_lock_irqsave(&info->irq_lock, flags);
+
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
+ goto out;

         if (info->xmit_cnt <= 0 || tty->stopped || !info->xmit_buf)
- return;
+ goto out;

- save_flags(flags); cli();
         if (!(info->IER & UART_IER_THRI)) {
                 info->IER |= UART_IER_THRI;
                 serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
                 serial_out(info, UART_ESI_CMD2, info->IER);
         }
- restore_flags(flags);
+out:
+ spin_unlock_irqrestore(&info->irq_lock, flags);
}

static int rs_write(struct tty_struct * tty,
@@ -1272,16 +1266,25 @@
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
         unsigned long flags;

- if (serial_paranoia_check(info, tty->name, "rs_write"))
- return 0;
+ spin_lock_irqsave(&info->irq_lock, flags);

- if (!tty || !info->xmit_buf || !tmp_buf)
- return 0;
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
+ goto out;
+
+ if (!tty || !info->xmit_buf)
+ goto out;

         while (1) {
                 /* Thanks to R. Wolff for suggesting how to do this with */
                 /* interrupts enabled */

+ /*
+ * Sorry about the interrupt-enabled trick, but it is not
+ * SMP-safe, since this is no longer protected by the 2.4-era
+ * write buffer semaphore. It needs to be done with the
+ * interrupt spinlock aquired - Jim Nelson
+ */
+
                 c = count;
                 t = ESP_XMIT_SIZE - info->xmit_cnt - 1;

@@ -1305,15 +1308,14 @@
                 ret += c;
         }

- save_flags(flags); cli();
-
         if (info->xmit_cnt && !tty->stopped && !(info->IER & UART_IER_THRI)) {
                 info->IER |= UART_IER_THRI;
                 serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
                 serial_out(info, UART_ESI_CMD2, info->IER);
         }

- restore_flags(flags);
+out:
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         return ret;
}

@@ -1322,7 +1324,7 @@
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
         int ret;

- if (serial_paranoia_check(info, tty->name, "rs_write_room"))
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
                 return 0;
         ret = ESP_XMIT_SIZE - info->xmit_cnt - 1;
         if (ret < 0)
@@ -1334,7 +1336,7 @@
{
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;

- if (serial_paranoia_check(info, tty->name, "rs_chars_in_buffer"))
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
                 return 0;
         return info->xmit_cnt;
}
@@ -1342,12 +1344,15 @@
static void rs_flush_buffer(struct tty_struct *tty)
{
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
-
- if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
+ unsigned long flags;
+
+ spin_lock_irqsave(&info->irq_lock, flags);
+ if (serial_paranoia_check(info, tty->name, __FUNCTION__)) {
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                 return;
- cli();
+ }
         info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
- sti();
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         tty_wakeup(tty);
}

@@ -1362,6 +1367,7 @@
static void rs_throttle(struct tty_struct * tty)
{
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
+ unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
         char buf[64];

@@ -1369,38 +1375,43 @@
                tty->ldisc.chars_in_buffer(tty));
#endif

- if (serial_paranoia_check(info, tty->name, "rs_throttle"))
- return;
+ spin_lock_irqsave(&info->irq_lock, flags);
+
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
+ goto out;

- cli();
         info->IER &= ~UART_IER_RDI;
         serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
         serial_out(info, UART_ESI_CMD2, info->IER);
         serial_out(info, UART_ESI_CMD1, ESI_SET_RX_TIMEOUT);
         serial_out(info, UART_ESI_CMD2, 0x00);
- sti();
+out:
+ spin_unlock_irqrestore(&info->irq_lock, flags);
}

static void rs_unthrottle(struct tty_struct * tty)
{
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
+ unsigned long flags;
#ifdef SERIAL_DEBUG_THROTTLE
         char buf[64];

         printk("unthrottle %s: %d....\n", tty_name(tty, buf),
                tty->ldisc.chars_in_buffer(tty));
#endif
+
+ spin_lock_irqsave(&info->irq_lock, flags);

- if (serial_paranoia_check(info, tty->name, "rs_unthrottle"))
- return;
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
+ goto out;

- cli();
         info->IER |= UART_IER_RDI;
         serial_out(info, UART_ESI_CMD1, ESI_SET_SRV_MASK);
         serial_out(info, UART_ESI_CMD2, info->IER);
         serial_out(info, UART_ESI_CMD1, ESI_SET_RX_TIMEOUT);
         serial_out(info, UART_ESI_CMD2, info->config.rx_timeout);
- sti();
+out:
+ spin_unlock_irqrestore(&info->irq_lock, flags);
}

/*
@@ -1573,6 +1584,7 @@
         unsigned int change_dma;
         int retval = 0;
         struct esp_struct *current_async;
+ unsigned long flags;

         /* Perhaps a non-sysadmin user should be able to do some of these */
         /* operations. I haven't decided yet. */
@@ -1650,26 +1662,24 @@

         if ((new_config.flow_off != info->config.flow_off) ||
             (new_config.flow_on != info->config.flow_on)) {
- unsigned long flags;

+ spin_lock_irqsave(&info->irq_lock, flags);
                 info->config.flow_off = new_config.flow_off;
                 info->config.flow_on = new_config.flow_on;
- save_flags(flags); cli();
                 serial_out(info, UART_ESI_CMD1, ESI_SET_FLOW_LVL);
                 serial_out(info, UART_ESI_CMD2, new_config.flow_off >> 8);
                 serial_out(info, UART_ESI_CMD2, new_config.flow_off);
                 serial_out(info, UART_ESI_CMD2, new_config.flow_on >> 8);
                 serial_out(info, UART_ESI_CMD2, new_config.flow_on);
- restore_flags(flags);
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         }

         if ((new_config.rx_trigger != info->config.rx_trigger) ||
             (new_config.tx_trigger != info->config.tx_trigger)) {
- unsigned long flags;

+ spin_lock_irqsave(&info->irq_lock, flags);
                 info->config.rx_trigger = new_config.rx_trigger;
                 info->config.tx_trigger = new_config.tx_trigger;
- save_flags(flags); cli();
                 serial_out(info, UART_ESI_CMD1, ESI_SET_TRIGGER);
                 serial_out(info, UART_ESI_CMD2,
                            new_config.rx_trigger >> 8);
@@ -1677,14 +1687,13 @@
                 serial_out(info, UART_ESI_CMD2,
                            new_config.tx_trigger >> 8);
                 serial_out(info, UART_ESI_CMD2, new_config.tx_trigger);
- restore_flags(flags);
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         }

         if (new_config.rx_timeout != info->config.rx_timeout) {
- unsigned long flags;

+ spin_lock_irqsave(&info->irq_lock, flags);
                 info->config.rx_timeout = new_config.rx_timeout;
- save_flags(flags); cli();

                 if (info->IER & UART_IER_RDI) {
                         serial_out(info, UART_ESI_CMD1,
@@ -1693,7 +1702,7 @@
                                    new_config.rx_timeout);
                 }

- restore_flags(flags);
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         }

         if (!(info->flags & ASYNC_INITIALIZED))
@@ -1716,11 +1725,12 @@
{
         unsigned char status;
         unsigned int result;
+ unsigned long flags;

- cli();
+ spin_lock_irqsave(&info->irq_lock, flags);
         serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
         status = serial_in(info, UART_ESI_STAT1);
- sti();
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         result = ((status & UART_LSR_TEMT) ? TIOCSER_TEMT : 0);
         return put_user(result,value);
}
@@ -1730,17 +1740,23 @@
{
         struct esp_struct * info = (struct esp_struct *)tty->driver_data;
         unsigned char control, status;
+ unsigned long flags;

- if (serial_paranoia_check(info, tty->name, __FUNCTION__))
+ spin_lock_irqsave(&info->irq_lock, flags);
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__))) {
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                 return -ENODEV;
- if (tty->flags & (1 << TTY_IO_ERROR))
+ }
+ if (unlikely(tty->flags & (1 << TTY_IO_ERROR))) {
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                 return -EIO;
+ }

         control = info->MCR;
- cli();
+
         serial_out(info, UART_ESI_CMD1, ESI_GET_UART_STAT);
         status = serial_in(info, UART_ESI_STAT2);
- sti();
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         return ((control & UART_MCR_RTS) ? TIOCM_RTS : 0)
                 | ((control & UART_MCR_DTR) ? TIOCM_DTR : 0)
                 | ((status & UART_MSR_DCD) ? TIOCM_CAR : 0)
@@ -1753,13 +1769,17 @@
                         unsigned int set, unsigned int clear)
{
         struct esp_struct * info = (struct esp_struct *)tty->driver_data;
+ unsigned long flags;

- if (serial_paranoia_check(info, tty->name, __FUNCTION__))
+ spin_lock_irqsave(&info->irq_lock, flags);
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__))) {
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                 return -ENODEV;
- if (tty->flags & (1 << TTY_IO_ERROR))
+ }
+ if (unlikely(tty->flags & (1 << TTY_IO_ERROR))) {
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                 return -EIO;
-
- cli();
+ }

         if (set & TIOCM_RTS)
                 info->MCR |= UART_MCR_RTS;
@@ -1774,7 +1794,7 @@
         serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
         serial_out(info, UART_ESI_CMD2, UART_MCR);
         serial_out(info, UART_ESI_CMD2, info->MCR);
- sti();
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         return 0;
}

@@ -1785,21 +1805,25 @@
{
         struct esp_struct * info = (struct esp_struct *)tty->driver_data;
         unsigned long flags;
-
- if (serial_paranoia_check(info, tty->name, "esp_break"))
+
+ spin_lock_irqsave(&info->irq_lock, flags);
+
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__))) {
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                 return;
+ }

- save_flags(flags); cli();
         if (break_state == -1) {
                 serial_out(info, UART_ESI_CMD1, ESI_ISSUE_BREAK);
                 serial_out(info, UART_ESI_CMD2, 0x01);
+ spin_unlock_irqrestore(&info->irq_lock, flags);

                 interruptible_sleep_on(&info->break_wait);
         } else {
                 serial_out(info, UART_ESI_CMD1, ESI_ISSUE_BREAK);
                 serial_out(info, UART_ESI_CMD2, 0x00);
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         }
- restore_flags(flags);
}

static int rs_ioctl(struct tty_struct *tty, struct file * file,
@@ -1809,8 +1833,9 @@
         struct async_icount cprev, cnow; /* kernel counter temps */
         struct serial_icounter_struct __user *p_cuser; /* user space */
         void __user *argp = (void __user *)arg;
+ unsigned long flags;

- if (serial_paranoia_check(info, tty->name, "rs_ioctl"))
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
                 return -ENODEV;

         if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
@@ -1849,17 +1874,17 @@
                  * Caller should use TIOCGICOUNT to see which one it was
                  */
                  case TIOCMIWAIT:
- cli();
+ spin_lock_irqsave(&info->irq_lock, flags);
                         cprev = info->icount; /* note the counters on entry */
- sti();
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                         while (1) {
                                 interruptible_sleep_on(&info->delta_msr_wait);
                                 /* see if a signal did it */
                                 if (signal_pending(current))
                                         return -ERESTARTSYS;
- cli();
+ spin_lock_irqsave(&info->irq_lock, flags);
                                 cnow = info->icount; /* atomic copy */
- sti();
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                                 if (cnow.rng == cprev.rng &&
                                     cnow.dsr == cprev.dsr &&
                                     cnow.dcd == cprev.dcd &&
@@ -1886,9 +1911,9 @@
                  * RI where only 0->1 is counted.
                  */
                 case TIOCGICOUNT:
- cli();
+ spin_lock_irqsave(&info->irq_lock, flags);
                         cnow = info->icount;
- sti();
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                         p_cuser = argp;
                         if (put_user(cnow.cts, &p_cuser->cts) ||
                             put_user(cnow.dsr, &p_cuser->dsr) ||
@@ -1911,6 +1936,7 @@
static void rs_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
         struct esp_struct *info = (struct esp_struct *)tty->driver_data;
+ unsigned long flags;

         if ( (tty->termios->c_cflag == old_termios->c_cflag)
             && ( RELEVANT_IFLAG(tty->termios->c_iflag)
@@ -1922,23 +1948,23 @@
         /* Handle transition to B0 status */
         if ((old_termios->c_cflag & CBAUD) &&
                 !(tty->termios->c_cflag & CBAUD)) {
+ spin_lock_irqsave(&info->irq_lock, flags);
                 info->MCR &= ~(UART_MCR_DTR|UART_MCR_RTS);
- cli();
                 serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
                 serial_out(info, UART_ESI_CMD2, UART_MCR);
                 serial_out(info, UART_ESI_CMD2, info->MCR);
- sti();
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         }

         /* Handle transition away from B0 status */
         if (!(old_termios->c_cflag & CBAUD) &&
                 (tty->termios->c_cflag & CBAUD)) {
+ spin_lock_irqsave(&info->irq_lock, flags);
                 info->MCR |= (UART_MCR_DTR | UART_MCR_RTS);
- cli();
                 serial_out(info, UART_ESI_CMD1, ESI_WRITE_UART);
                 serial_out(info, UART_ESI_CMD2, UART_MCR);
                 serial_out(info, UART_ESI_CMD2, info->MCR);
- sti();
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         }

         /* Handle turning of CRTSCTS */
@@ -1975,10 +2001,11 @@
         struct esp_struct * info = (struct esp_struct *)tty->driver_data;
         unsigned long flags;

- if (!info || serial_paranoia_check(info, tty->name, "rs_close"))
- return;
-
- save_flags(flags); cli();
+ spin_lock_irqsave(&info->irq_lock, flags);
+
+ if (unlikely(!info ||
+ serial_paranoia_check(info, tty->name, __FUNCTION__)))
+ goto out;

         if (tty_hung_up_p(filp)) {
                 DBG_CNT("before DEC-hung");
@@ -2058,7 +2085,7 @@
         info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING);
         wake_up_interruptible(&info->close_wait);
out:
- restore_flags(flags);
+ spin_unlock_irqrestore(&info->irq_lock, flags);
}

static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
@@ -2067,8 +2094,9 @@
         unsigned long orig_jiffies, char_time;
         unsigned long flags;

- if (serial_paranoia_check(info, tty->name, "rs_wait_until_sent"))
- return;
+ spin_lock_irqsave(&info->irq_lock, flags);
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
+ goto out;

         orig_jiffies = jiffies;
         char_time = ((info->timeout - HZ / 50) / 1024) / 5;
@@ -2076,13 +2104,15 @@
         if (!char_time)
                 char_time = 1;

- save_flags(flags); cli();
         serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
         serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);

         while ((serial_in(info, UART_ESI_STAT1) != 0x03) ||
                 (serial_in(info, UART_ESI_STAT2) != 0xff)) {
+
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                 msleep_interruptible(jiffies_to_msecs(char_time));
+ spin_lock_irqsave(&info->irq_lock, flags);

                 if (signal_pending(current))
                         break;
@@ -2093,8 +2123,8 @@
                 serial_out(info, UART_ESI_CMD1, ESI_NO_COMMAND);
                 serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);
         }
-
- restore_flags(flags);
+
+out: spin_unlock_irqrestore(&info->irq_lock, flags);
         set_current_state(TASK_RUNNING);
}

@@ -2105,7 +2135,7 @@
{
         struct esp_struct * info = (struct esp_struct *)tty->driver_data;

- if (serial_paranoia_check(info, tty->name, "esp_hangup"))
+ if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
                 return;

         rs_flush_buffer(tty);
@@ -2174,15 +2204,13 @@
         printk("block_til_ready before block: ttys%d, count = %d\n",
                info->line, info->count);
#endif
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&info->irq_lock, flags);
         if (!tty_hung_up_p(filp))
                 info->count--;
- restore_flags(flags);
+ spin_unlock_irqrestore(&info->irq_lock, flags);
         info->blocked_open++;
         while (1) {
- save_flags(flags);
- cli();
+ spin_lock_irqsave(&info->irq_lock, flags);
                 if ((tty->termios->c_cflag & CBAUD)) {
                         unsigned int scratch;

@@ -2194,7 +2222,7 @@
                         serial_out(info, UART_ESI_CMD2,
                                 scratch | UART_MCR_DTR | UART_MCR_RTS);
                 }
- restore_flags(flags);
+ spin_unlock_irqrestore(&info->irq_lock, flags);
                 set_current_state(TASK_INTERRUPTIBLE);
                 if (tty_hung_up_p(filp) ||
                     !(info->flags & ASYNC_INITIALIZED)) {
@@ -2264,7 +2292,7 @@
                 info = info->next_port;

         if (!info) {
- serial_paranoia_check(info, tty->name, "esp_open");
+ serial_paranoia_check(info, tty->name, __FUNCTION__);
                 return -ENODEV;
         }

@@ -2275,12 +2303,6 @@
         tty->driver_data = info;
         info->tty = tty;

- if (!tmp_buf) {
- tmp_buf = (unsigned char *) get_zeroed_page(GFP_KERNEL);
- if (!tmp_buf)
- return -ENOMEM;
- }
-
         /*
          * Start up serial port
          */
@@ -2335,7 +2357,7 @@
         if (!request_region(info->port, REGION_SIZE, "esp serial"))
                 return -EIO;

- save_flags(flags); cli();
+ spin_lock_irqsave(&info->irq_lock, flags);

         /*
          * Check for ESP card
@@ -2369,10 +2391,11 @@
                         serial_out(info, UART_ESI_CMD2, 0x00);
                 }
         }
+ spin_unlock_irqrestore(&info->irq_lock, flags);
+
         if (!port_detected)
                 release_region(info->port, REGION_SIZE);

- restore_flags(flags);
         return (port_detected);
}

@@ -2513,6 +2536,7 @@
                 init_waitqueue_head(&info->close_wait);
                 init_waitqueue_head(&info->delta_msr_wait);
                 init_waitqueue_head(&info->break_wait);
+ spin_lock_init(&info->irq_lock);
                 ports = info;
                 printk(KERN_INFO "ttyP%d at 0x%04x (irq = %d) is an ESP ",
                         info->line, info->port, info->irq);
@@ -2563,18 +2587,14 @@

static void __exit espserial_exit(void)
{
- unsigned long flags;
         int e1;
         struct esp_struct *temp_async;
         struct esp_pio_buffer *pio_buf;

         /* printk("Unloading %s: version %s\n", serial_name, serial_version); */
- save_flags(flags);
- cli();
         if ((e1 = tty_unregister_driver(esp_driver)))
- printk("SERIAL: failed to unregister serial driver (%d)\n",
- e1);
- restore_flags(flags);
+ printk(KERN_ERR "SERIAL: failed to unregister serial driver"
+ " (%d)\n", e1);
         put_tty_driver(esp_driver);

         while (ports) {
@@ -2590,9 +2610,6 @@
                 free_pages((unsigned long)dma_buffer,
                         get_order(DMA_BUFFER_SZ));

- if (tmp_buf)
- free_page((unsigned long)tmp_buf);
-
         while (free_pio_buf) {
                 pio_buf = free_pio_buf->next;
                 kfree(free_pio_buf);
diff -urN --exclude='*~' linux-2.6.10-original/drivers/char/Kconfig linux-2.6.10/drivers/char/Kconfig
--- linux-2.6.10-original/drivers/char/Kconfig 2004-12-24 16:33:49.000000000 -0500
+++ linux-2.6.10/drivers/char/Kconfig 2004-12-30 20:25:12.945068082 -0500
@@ -170,7 +170,7 @@

config ESPSERIAL
         tristate "Hayes ESP serial port support"
- depends on SERIAL_NONSTANDARD && ISA && BROKEN_ON_SMP
+ depends on SERIAL_NONSTANDARD && ISA
         help
           This is a driver which supports Hayes ESP serial ports. Both single
           port cards and multiport cards are supported. Make sure to read
diff -urN --exclude='*~' linux-2.6.10-original/include/linux/hayesesp.h linux-2.6.10/include/linux/hayesesp.h
--- linux-2.6.10-original/include/linux/hayesesp.h 2004-12-24 16:35:24.000000000 -0500
+++ linux-2.6.10/include/linux/hayesesp.h 2004-12-30 18:15:06.541960410 -0500
@@ -108,6 +108,7 @@
         wait_queue_head_t break_wait;
         struct async_icount icount; /* kernel counters for the 4 input interrupts */
         struct hayes_esp_config config; /* port configuration */
+ spinlock_t irq_lock;
         struct esp_struct *next_port; /* For the linked list */
};

-
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