[PATCH] generic-serial

From: Patrick van de Lageweg
Date: Wed Dec 08 2004 - 08:42:05 EST

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Hi,

This patch converts all save_flags/restore_flags to the new
spin_lick_irqsave/spin_unlock_irqrestore calls, as well as some
other 2.6.X cleanups. This prepares the way for the "io8+",
"sx" and "rio" drivers to become SMP safe. Patches for those
drivers follow.

Signed-off-by: Patrick vd Lageweg <patrick@xxxxxxxxxxxx>
Signed-off-by: Rogier Wolff <R.E.Wolff@xxxxxxxxxxxx>

Patrick
diff -u -r linux-2.6.10-rc3-clean/drivers/char/generic_serial.c linux-2.6.10-rc3-generix-serial/drivers/char/generic_serial.c
--- linux-2.6.10-rc3-clean/drivers/char/generic_serial.c Fri Dec 3 15:13:32 2004
+++ linux-2.6.10-rc3-generix-serial/drivers/char/generic_serial.c Fri Dec 3 15:23:37 2004
@@ -26,6 +26,7 @@
#include <linux/mm.h>
#include <linux/generic_serial.h>
#include <linux/interrupt.h>
+#include <linux/tty_flip.h>
#include <linux/delay.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>
@@ -45,8 +46,8 @@

#define func_enter() gs_dprintk (GS_DEBUG_FLOW, "gs: enter %s\n", __FUNCTION__)
#define func_exit() gs_dprintk (GS_DEBUG_FLOW, "gs: exit %s\n", __FUNCTION__)
-
-#ifdef NEW_WRITE_LOCKING
+#define NEW_WRITE_LOCKING 1
+#if NEW_WRITE_LOCKING
#define DECL /* Nothing */
#define LOCKIT down (& port->port_write_sem);
#define RELEASEIT up (&port->port_write_sem);
@@ -208,7 +209,7 @@
if (!port || !port->xmit_buf || !tmp_buf)
return -EIO;

- save_flags(flags);
+ local_save_flags(flags);
while (1) {
cli();
c = count;
@@ -227,14 +228,14 @@

/* Can't copy more? break out! */
if (c <= 0) {
- restore_flags(flags);
+ local_restore_flags(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);
+ local_restore_flags(flags);
buf += c;
count -= c;
total += c;
@@ -380,9 +381,9 @@
if (!port) return;

/* XXX Would the write semaphore do? */
- save_flags(flags); cli();
+ spin_lock_irqsave (&port->driver_lock, flags);
port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
- restore_flags(flags);
+ spin_unlock_irqrestore (&port->driver_lock, flags);

wake_up_interruptible(&tty->write_wait);
tty_wakeup(tty);
@@ -468,8 +469,7 @@
if (!(port->flags & ASYNC_INITIALIZED))
return;

- save_flags (flags);
- cli ();
+ spin_lock_irqsave(&port->driver_lock, flags);

if (port->xmit_buf) {
free_page((unsigned long) port->xmit_buf);
@@ -482,7 +482,7 @@
port->rd->shutdown_port (port);

port->flags &= ~ASYNC_INITIALIZED;
- restore_flags (flags);
+ spin_unlock_irqrestore(&port->driver_lock, flags);

func_exit();
}
@@ -540,6 +540,7 @@
int do_clocal = 0;
int CD;
struct tty_struct *tty;
+ unsigned long flags;

func_enter ();

@@ -591,10 +592,11 @@
add_wait_queue(&port->open_wait, &wait);

gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n");
- cli();
- if (!tty_hung_up_p(filp))
+ spin_lock_irqsave(&port->driver_lock, flags);
+ if (!tty_hung_up_p(filp)) {
port->count--;
- sti();
+ }
+ spin_unlock_irqrestore(&port->driver_lock, flags);
port->blocked_open++;
while (1) {
CD = port->rd->get_CD (port);
@@ -623,8 +625,9 @@
port->blocked_open);
set_current_state (TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait);
- if (!tty_hung_up_p(filp))
+ if (!tty_hung_up_p(filp)) {
port->count++;
+ }
port->blocked_open--;
if (retval)
return retval;
@@ -654,27 +657,29 @@
port->tty = tty;
}

- save_flags(flags); cli();
+ spin_lock_irqsave(&port->driver_lock, flags);

if (tty_hung_up_p(filp)) {
- restore_flags(flags);
- port->rd->hungup (port);
+ spin_unlock_irqrestore(&port->driver_lock, flags);
+ if (port->rd->hungup)
+ port->rd->hungup (port);
func_exit ();
return;
}

if ((tty->count == 1) && (port->count != 1)) {
- printk(KERN_ERR "gs: gs_close: bad port count;"
- " tty->count is 1, port count is %d\n", port->count);
+ printk(KERN_ERR "gs: gs_close port %p: bad port count;"
+ " tty->count is 1, port count is %d\n", port, port->count);
port->count = 1;
}
if (--port->count < 0) {
- printk(KERN_ERR "gs: gs_close: bad port count: %d\n", port->count);
+ printk(KERN_ERR "gs: gs_close port %p: bad port count: %d\n", port, port->count);
port->count = 0;
}
+
if (port->count) {
- gs_dprintk(GS_DEBUG_CLOSE, "gs_close: count: %d\n", port->count);
- restore_flags(flags);
+ gs_dprintk(GS_DEBUG_CLOSE, "gs_close port %p: count: %d\n", port, port->count);
+ spin_unlock_irqrestore(&port->driver_lock, flags);
func_exit ();
return;
}
@@ -696,16 +701,17 @@
*/

port->rd->disable_rx_interrupts (port);
+ spin_unlock_irqrestore(&port->driver_lock, flags);

/* close has no way of returning "EINTR", so discard return value */
if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
- gs_wait_tx_flushed (port, port->closing_wait);
+ gs_wait_tx_flushed (port, port->closing_wait);

port->flags &= ~GS_ACTIVE;

if (tty->driver->flush_buffer)
tty->driver->flush_buffer(tty);
-
+
tty_ldisc_flush(tty);
tty->closing = 0;

@@ -716,14 +722,15 @@

if (port->blocked_open) {
if (port->close_delay) {
+ spin_unlock_irqrestore(&port->driver_lock, flags);
msleep_interruptible(jiffies_to_msecs(port->close_delay));
+ spin_lock_irqsave(&port->driver_lock, flags);
}
wake_up_interruptible(&port->open_wait);
}
port->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING | ASYNC_INITIALIZED);
wake_up_interruptible(&port->close_wait);

- restore_flags(flags);
func_exit ();
}

@@ -748,6 +755,12 @@
port = tty->driver_data;

if (!port) return;
+ if (!port->tty) {
+ /* This seems to happen when this is called after gs_close. */
+ gs_dprintk (GS_DEBUG_TERMIOS, "gs: Odd: port->tty is NULL\n");
+ port->tty = tty;
+ }
+

tiosp = tty->termios;

@@ -842,7 +855,7 @@

if (!(old_termios->c_cflag & CLOCAL) &&
(tty->termios->c_cflag & CLOCAL))
- wake_up_interruptible(&info->open_wait);
+ wake_up_interruptible(&port->gs.open_wait);
#endif

func_exit();
@@ -857,56 +870,56 @@
unsigned long flags;
unsigned long page;

- save_flags (flags);
- if (!tmp_buf) {
- page = get_zeroed_page(GFP_KERNEL);
+ func_enter ();

- cli (); /* Don't expect this to make a difference. */
+ if (!tmp_buf) {
+ page = get_zeroed_page(GFP_KERNEL);
+ spin_lock_irqsave (&port->driver_lock, flags); /* Don't expect this to make a difference. */
if (tmp_buf)
free_page(page);
else
tmp_buf = (unsigned char *) page;
- restore_flags (flags);
-
+ spin_unlock_irqrestore (&port->driver_lock, flags);
if (!tmp_buf) {
+ func_exit ();
return -ENOMEM;
}
}

- if (port->flags & ASYNC_INITIALIZED)
+ if (port->flags & ASYNC_INITIALIZED) {
+ func_exit ();
return 0;
-
+ }
if (!port->xmit_buf) {
/* We may sleep in get_zeroed_page() */
unsigned long tmp;

tmp = get_zeroed_page(GFP_KERNEL);
-
- /* Spinlock? */
- cli ();
+ spin_lock_irqsave (&port->driver_lock, flags);
if (port->xmit_buf)
free_page (tmp);
else
port->xmit_buf = (unsigned char *) tmp;
- restore_flags (flags);
-
- if (!port->xmit_buf)
+ spin_unlock_irqrestore(&port->driver_lock, flags);
+ if (!port->xmit_buf) {
+ func_exit ();
return -ENOMEM;
+ }
}

- cli();
-
+ spin_lock_irqsave (&port->driver_lock, flags);
if (port->tty)
clear_bit(TTY_IO_ERROR, &port->tty->flags);
-
+ init_MUTEX(&port->port_write_sem);
port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
-
+ spin_unlock_irqrestore(&port->driver_lock, flags);
gs_set_termios(port->tty, NULL);
-
+ spin_lock_irqsave (&port->driver_lock, flags);
port->flags |= ASYNC_INITIALIZED;
port->flags &= ~GS_TX_INTEN;

- restore_flags(flags);
+ spin_unlock_irqrestore(&port->driver_lock, flags);
+ func_exit ();
return 0;
}

@@ -977,13 +990,15 @@

void gs_got_break(struct gs_port *port)
{
+ func_enter ();
+
+ tty_insert_flip_char(port->tty, 0, TTY_BREAK);
+ tty_schedule_flip(port->tty);
if (port->flags & ASYNC_SAK) {
do_SAK (port->tty);
}
- *(port->tty->flip.flag_buf_ptr) = TTY_BREAK;
- port->tty->flip.flag_buf_ptr++;
- port->tty->flip.char_buf_ptr++;
- port->tty->flip.count++;
+
+ func_exit ();
}

diff -u -r linux-2.6.10-rc3-clean/include/linux/generic_serial.h linux-2.6.10-rc3-generix-serial/include/linux/generic_serial.h
--- linux-2.6.10-rc3-clean/include/linux/generic_serial.h Fri Dec 3 15:14:23 2004
+++ linux-2.6.10-rc3-generix-serial/include/linux/generic_serial.h Fri Dec 3 15:23:37 2004
@@ -34,7 +34,7 @@
int xmit_head;
int xmit_tail;
int xmit_cnt;
- /* struct semaphore port_write_sem; */
+ struct semaphore port_write_sem;
int flags;
wait_queue_head_t open_wait;
wait_queue_head_t close_wait;
@@ -49,6 +49,7 @@
int baud_base;
int baud;
int custom_divisor;
+ spinlock_t driver_lock;
};

@@ -70,6 +71,7 @@
#define GS_DEBUG_STUFF 0x00000008
#define GS_DEBUG_CLOSE 0x00000010
#define GS_DEBUG_FLOW 0x00000020
+#define GS_DEBUG_WRITE 0x00000040

void gs_put_char(struct tty_struct *tty, unsigned char ch);

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