Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff
[linux-2.6.git] / arch / um / drivers / line.c
index d4286de..6c2d4cc 100644 (file)
@@ -1,4 +1,4 @@
-/* 
+/*
  * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
  * Licensed under the GPL
  */
@@ -23,8 +23,9 @@
 
 static irqreturn_t line_interrupt(int irq, void *data, struct pt_regs *unused)
 {
-       struct tty_struct *tty = data;
-       struct line *line = tty->driver_data;
+       struct chan *chan = data;
+       struct line *line = chan->line;
+       struct tty_struct *tty = line->tty;
 
        if (line)
                chan_interrupt(&line->chan_list, &line->task, tty, irq);
@@ -33,25 +34,76 @@ static irqreturn_t line_interrupt(int irq, void *data, struct pt_regs *unused)
 
 static void line_timer_cb(void *arg)
 {
-       struct tty_struct *tty = arg;
-       struct line *line = tty->driver_data;
+       struct line *line = arg;
 
-       line_interrupt(line->driver->read_irq, arg, NULL);
+       if(!line->throttled)
+               chan_interrupt(&line->chan_list, &line->task, line->tty,
+                              line->driver->read_irq);
 }
 
-static int write_room(struct line *dev)
+/* Returns the free space inside the ring buffer of this line.
+ *
+ * Should be called while holding line->lock (this does not modify datas).
+ */
+static int write_room(struct line *line)
 {
        int n;
 
-       if (dev->buffer == NULL)
-               return (LINE_BUFSIZE - 1);
+       if (line->buffer == NULL)
+               return LINE_BUFSIZE - 1;
+
+       /* This is for the case where the buffer is wrapped! */
+       n = line->head - line->tail;
 
-       n = dev->head - dev->tail;
        if (n <= 0)
-               n = LINE_BUFSIZE + n;
-       return (n - 1);
+               n = LINE_BUFSIZE + n; /* The other case */
+       return n - 1;
+}
+
+int line_write_room(struct tty_struct *tty)
+{
+       struct line *line = tty->driver_data;
+       unsigned long flags;
+       int room;
+
+       if (tty->stopped)
+               return 0;
+
+       spin_lock_irqsave(&line->lock, flags);
+       room = write_room(line);
+       spin_unlock_irqrestore(&line->lock, flags);
+
+       /*XXX: Warning to remove */
+       if (0 == room)
+               printk(KERN_DEBUG "%s: %s: no room left in buffer\n",
+                      __FUNCTION__,tty->name);
+       return room;
+}
+
+int line_chars_in_buffer(struct tty_struct *tty)
+{
+       struct line *line = tty->driver_data;
+       unsigned long flags;
+       int ret;
+
+       spin_lock_irqsave(&line->lock, flags);
+
+       /*write_room subtracts 1 for the needed NULL, so we readd it.*/
+       ret = LINE_BUFSIZE - (write_room(line) + 1);
+       spin_unlock_irqrestore(&line->lock, flags);
+
+       return ret;
 }
 
+/*
+ * This copies the content of buf into the circular buffer associated with
+ * this line.
+ * The return value is the number of characters actually copied, i.e. the ones
+ * for which there was space: this function is not supposed to ever flush out
+ * the circular buffer.
+ *
+ * Must be called while holding line->lock!
+ */
 static int buffer_data(struct line *line, const char *buf, int len)
 {
        int end, room;
@@ -70,48 +122,96 @@ static int buffer_data(struct line *line, const char *buf, int len)
        len = (len > room) ? room : len;
 
        end = line->buffer + LINE_BUFSIZE - line->tail;
-       if(len < end){
+
+       if (len < end){
                memcpy(line->tail, buf, len);
                line->tail += len;
        }
        else {
+               /* The circular buffer is wrapping */
                memcpy(line->tail, buf, end);
                buf += end;
                memcpy(line->buffer, buf, len - end);
                line->tail = line->buffer + len - end;
        }
 
-       return(len);
+       return len;
 }
 
+/*
+ * Flushes the ring buffer to the output channels. That is, write_chan is
+ * called, passing it line->head as buffer, and an appropriate count.
+ *
+ * On exit, returns 1 when the buffer is empty,
+ * 0 when the buffer is not empty on exit,
+ * and -errno when an error occurred.
+ *
+ * Must be called while holding line->lock!*/
 static int flush_buffer(struct line *line)
 {
        int n, count;
 
        if ((line->buffer == NULL) || (line->head == line->tail))
-               return(1);
+               return 1;
 
        if (line->tail < line->head) {
+               /* line->buffer + LINE_BUFSIZE is the end of the buffer! */
                count = line->buffer + LINE_BUFSIZE - line->head;
+
                n = write_chan(&line->chan_list, line->head, count,
                               line->driver->write_irq);
                if (n < 0)
-                       return(n);
-               if (n == count)
+                       return n;
+               if (n == count) {
+                       /* We have flushed from ->head to buffer end, now we
+                        * must flush only from the beginning to ->tail.*/
                        line->head = line->buffer;
-               else {
+               else {
                        line->head += n;
-                       return(0);
+                       return 0;
                }
        }
 
        count = line->tail - line->head;
-       n = write_chan(&line->chan_list, line->head, count, 
+       n = write_chan(&line->chan_list, line->head, count,
                       line->driver->write_irq);
-       if(n < 0) return(n);
+
+       if(n < 0)
+               return n;
 
        line->head += n;
-       return(line->head == line->tail);
+       return line->head == line->tail;
+}
+
+void line_flush_buffer(struct tty_struct *tty)
+{
+       struct line *line = tty->driver_data;
+       unsigned long flags;
+       int err;
+
+       /*XXX: copied from line_write, verify if it is correct!*/
+       if(tty->stopped)
+               return;
+               //return 0;
+
+       spin_lock_irqsave(&line->lock, flags);
+       err = flush_buffer(line);
+       /*if (err == 1)
+               err = 0;*/
+       spin_unlock_irqrestore(&line->lock, flags);
+       //return err;
+}
+
+/* We map both ->flush_chars and ->put_char (which go in pair) onto ->flush_buffer
+ * and ->write. Hope it's not that bad.*/
+void line_flush_chars(struct tty_struct *tty)
+{
+       line_flush_buffer(tty);
+}
+
+void line_put_char(struct tty_struct *tty, unsigned char ch)
+{
+       line_write(tty, &ch, sizeof(ch));
 }
 
 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
@@ -120,38 +220,31 @@ int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
        unsigned long flags;
        int n, err, ret = 0;
 
-       if(tty->stopped) return 0;
+       if(tty->stopped)
+               return 0;
 
-       down(&line->sem);
-       if(line->head != line->tail){
-               local_irq_save(flags);
+       spin_lock_irqsave(&line->lock, flags);
+       if (line->head != line->tail) {
                ret = buffer_data(line, buf, len);
                err = flush_buffer(line);
-               local_irq_restore(flags);
-               if(err <= 0)
+               if (err <= 0 && (err != -EAGAIN || !ret))
                        ret = err;
-       }
-       else {
-               n = write_chan(&line->chan_list, buf, len, 
+       } else {
+               n = write_chan(&line->chan_list, buf, len,
                               line->driver->write_irq);
-               if(n < 0){
+               if (n < 0) {
                        ret = n;
                        goto out_up;
                }
 
                len -= n;
                ret += n;
-               if(len > 0)
+               if (len > 0)
                        ret += buffer_data(line, buf + n, len);
        }
- out_up:
-       up(&line->sem);
-       return(ret);
-}
-
-void line_put_char(struct tty_struct *tty, unsigned char ch)
-{
-       line_write(tty, &ch, sizeof(ch));
+out_up:
+       spin_unlock_irqrestore(&line->lock, flags);
+       return ret;
 }
 
 void line_set_termios(struct tty_struct *tty, struct termios * old)
@@ -159,11 +252,6 @@ void line_set_termios(struct tty_struct *tty, struct termios * old)
        /* nothing */
 }
 
-int line_chars_in_buffer(struct tty_struct *tty)
-{
-       return 0;
-}
-
 static struct {
        int  cmd;
        char *level;
@@ -250,133 +338,155 @@ int line_ioctl(struct tty_struct *tty, struct file * file,
                ret = -ENOIOCTLCMD;
                break;
        }
-       return(ret);
+       return ret;
+}
+
+void line_throttle(struct tty_struct *tty)
+{
+       struct line *line = tty->driver_data;
+
+       deactivate_chan(&line->chan_list, line->driver->read_irq);
+       line->throttled = 1;
+}
+
+void line_unthrottle(struct tty_struct *tty)
+{
+       struct line *line = tty->driver_data;
+
+       line->throttled = 0;
+       chan_interrupt(&line->chan_list, &line->task, tty,
+                      line->driver->read_irq);
+
+       /* Maybe there is enough stuff pending that calling the interrupt
+        * throttles us again.  In this case, line->throttled will be 1
+        * again and we shouldn't turn the interrupt back on.
+        */
+       if(!line->throttled)
+               reactivate_chan(&line->chan_list, line->driver->read_irq);
 }
 
 static irqreturn_t line_write_interrupt(int irq, void *data,
                                        struct pt_regs *unused)
 {
-       struct tty_struct *tty = data;
-       struct line *line = tty->driver_data;
+       struct chan *chan = data;
+       struct line *line = chan->line;
+       struct tty_struct *tty = line->tty;
        int err;
 
+       /* Interrupts are enabled here because we registered the interrupt with
+        * SA_INTERRUPT (see line_setup_irq).*/
+
+       spin_lock_irq(&line->lock);
        err = flush_buffer(line);
-       if(err == 0)
-               return(IRQ_NONE);
-       else if(err < 0){
+       if (err == 0) {
+               return IRQ_NONE;
+       } else if(err < 0) {
                line->head = line->buffer;
                line->tail = line->buffer;
        }
+       spin_unlock_irq(&line->lock);
 
        if(tty == NULL)
-               return(IRQ_NONE);
+               return IRQ_NONE;
 
-       if(test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
+       if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
           (tty->ldisc.write_wakeup != NULL))
                (tty->ldisc.write_wakeup)(tty);
-       
+
        /* BLOCKING mode
         * In blocking mode, everything sleeps on tty->write_wait.
         * Sleeping in the console driver would break non-blocking
         * writes.
         */
 
-       if(waitqueue_active(&tty->write_wait))
+       if (waitqueue_active(&tty->write_wait))
                wake_up_interruptible(&tty->write_wait);
-       return(IRQ_HANDLED);
+       return IRQ_HANDLED;
 }
 
-int line_setup_irq(int fd, int input, int output, struct tty_struct *tty)
+int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
 {
-       struct line *line = tty->driver_data;
        struct line_driver *driver = line->driver;
        int err = 0, flags = SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM;
 
-       if(input) err = um_request_irq(driver->read_irq, fd, IRQ_READ, 
-                                      line_interrupt, flags, 
-                                      driver->read_irq_name, tty);
-       if(err) return(err);
-       if(output) err = um_request_irq(driver->write_irq, fd, IRQ_WRITE, 
-                                       line_write_interrupt, flags, 
-                                       driver->write_irq_name, tty);
+       if (input)
+               err = um_request_irq(driver->read_irq, fd, IRQ_READ,
+                                      line_interrupt, flags,
+                                      driver->read_irq_name, data);
+       if (err)
+               return err;
+       if (output)
+               err = um_request_irq(driver->write_irq, fd, IRQ_WRITE,
+                                       line_write_interrupt, flags,
+                                       driver->write_irq_name, data);
        line->have_irq = 1;
-       return(err);
-}
-
-void line_disable(struct tty_struct *tty, int current_irq)
-{
-       struct line *line = tty->driver_data;
-
-       if(!line->have_irq)
-               return;
-
-       if(line->driver->read_irq == current_irq)
-               free_irq_later(line->driver->read_irq, tty);
-       else {
-               free_irq_by_irq_and_dev(line->driver->read_irq, tty);
-               free_irq(line->driver->read_irq, tty);
-       }
-
-       if(line->driver->write_irq == current_irq)
-               free_irq_later(line->driver->write_irq, tty);
-       else {
-               free_irq_by_irq_and_dev(line->driver->write_irq, tty);
-               free_irq(line->driver->write_irq, tty);
-       }
-
-       line->have_irq = 0;
+       return err;
 }
 
-int line_open(struct line *lines, struct tty_struct *tty,
-             struct chan_opts *opts)
+int line_open(struct line *lines, struct tty_struct *tty)
 {
        struct line *line;
-       int err = 0;
+       int err = -ENODEV;
 
        line = &lines[tty->index];
        tty->driver_data = line;
 
-       down(&line->sem);
-       if (tty->count == 1) {
-               if (!line->valid) {
-                       err = -ENODEV;
-                       goto out;
-               }
-               if (list_empty(&line->chan_list)) {
-                       err = parse_chan_pair(line->init_str, &line->chan_list,
-                                             line->init_pri, tty->index, opts);
-                       if(err) goto out;
-                       err = open_chan(&line->chan_list);
-                       if(err) goto out;
+       /* The IRQ which takes this lock is not yet enabled and won't be run
+        * before the end, so we don't need to use spin_lock_irq.*/
+       spin_lock(&line->lock);
+
+       tty->driver_data = line;
+       line->tty = tty;
+       if(!line->valid)
+               goto out;
+
+       if(tty->count == 1){
+               /* Here the device is opened, if necessary, and interrupt
+                * is registered.
+                */
+               enable_chan(line);
+               INIT_WORK(&line->task, line_timer_cb, line);
+
+               if(!line->sigio){
+                       chan_enable_winch(&line->chan_list, tty);
+                       line->sigio = 1;
                }
-               enable_chan(&line->chan_list, tty);
-               INIT_WORK(&line->task, line_timer_cb, tty);
-       }
 
-       if(!line->sigio){
-               chan_enable_winch(&line->chan_list, tty);
-               line->sigio = 1;
+               chan_window_size(&line->chan_list, &tty->winsize.ws_row,
+                                &tty->winsize.ws_col);
        }
-       chan_window_size(&line->chan_list, &tty->winsize.ws_row,
-                        &tty->winsize.ws_col);
-       line->count++;
 
+       err = 0;
 out:
-       up(&line->sem);
-       return(err);
+       spin_unlock(&line->lock);
+       return err;
 }
 
+static void unregister_winch(struct tty_struct *tty);
+
 void line_close(struct tty_struct *tty, struct file * filp)
 {
        struct line *line = tty->driver_data;
 
-       down(&line->sem);
-       line->count--;
-       if (tty->count == 1) {
-               line_disable(tty, -1);
+       /* XXX: I assume this should be called in process context, not with
+         *  interrupts disabled!
+         */
+       spin_lock_irq(&line->lock);
+
+       /* We ignore the error anyway! */
+       flush_buffer(line);
+
+       if(tty->count == 1){
+               line->tty = NULL;
                tty->driver_data = NULL;
-       }
-       up(&line->sem);
+
+               if(line->sigio){
+                       unregister_winch(tty);
+                       line->sigio = 0;
+               }
+        }
+
+       spin_unlock_irq(&line->lock);
 }
 
 void close_lines(struct line *lines, int nlines)
@@ -384,34 +494,44 @@ void close_lines(struct line *lines, int nlines)
        int i;
 
        for(i = 0; i < nlines; i++)
-               close_chan(&lines[i].chan_list);
+               close_chan(&lines[i].chan_list, 0);
 }
 
-int line_setup(struct line *lines, int num, char *init, int all_allowed)
+/* Common setup code for both startup command line and mconsole initialization.
+ * @lines contains the the array (of size @num) to modify;
+ * @init is the setup string;
+ */
+
+int line_setup(struct line *lines, unsigned int num, char *init)
 {
        int i, n;
        char *end;
 
-       if(*init == '=') n = -1;
+       if(*init == '=') {
+               /* We said con=/ssl= instead of con#=, so we are configuring all
+                * consoles at once.*/
+               n = -1;
+       }
        else {
                n = simple_strtoul(init, &end, 0);
                if(*end != '='){
-                       printk(KERN_ERR "line_setup failed to parse \"%s\"\n", 
+                       printk(KERN_ERR "line_setup failed to parse \"%s\"\n",
                               init);
-                       return(0);
+                       return 0;
                }
                init = end;
        }
        init++;
-       if((n >= 0) && (n >= num)){
+
+       if (n >= (signed int) num) {
                printk("line_setup - %d out of range ((0 ... %d) allowed)\n",
                       n, num - 1);
-               return(0);
+               return 0;
        }
        else if (n >= 0){
-               if (lines[n].count > 0) {
+               if (lines[n].tty != NULL) {
                        printk("line_setup - device %d is open\n", n);
-                       return(0);
+                       return 0;
                }
                if (lines[n].init_pri <= INIT_ONE){
                        lines[n].init_pri = INIT_ONE;
@@ -420,14 +540,9 @@ int line_setup(struct line *lines, int num, char *init, int all_allowed)
                        else {
                                lines[n].init_str = init;
                                lines[n].valid = 1;
-                       }       
+                       }
                }
        }
-       else if(!all_allowed){
-               printk("line_setup - can't configure all devices from "
-                      "mconsole\n");
-               return(0);
-       }
        else {
                for(i = 0; i < num; i++){
                        if(lines[i].init_pri <= INIT_ALL){
@@ -440,21 +555,36 @@ int line_setup(struct line *lines, int num, char *init, int all_allowed)
                        }
                }
        }
-       return(1);
+       return n == -1 ? num : n;
 }
 
-int line_config(struct line *lines, int num, char *str)
+int line_config(struct line *lines, unsigned int num, char *str,
+               struct chan_opts *opts)
 {
-       char *new = uml_strdup(str);
+       struct line *line;
+       char *new;
+       int n;
+
+       if(*str == '='){
+               printk("line_config - can't configure all devices from "
+                      "mconsole\n");
+               return 1;
+       }
 
+       new = kstrdup(str, GFP_KERNEL);
        if(new == NULL){
-               printk("line_config - uml_strdup failed\n");
-               return(-ENOMEM);
+               printk("line_config - kstrdup failed\n");
+               return 1;
        }
-       return(!line_setup(lines, num, new, 0));
+       n = line_setup(lines, num, new);
+       if(n < 0)
+               return 1;
+
+       line = &lines[n];
+       return parse_chan_pair(line->init_str, line, n, opts);
 }
 
-int line_get_config(char *name, struct line *lines, int num, char *str, 
+int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
                    int size, char **error_out)
 {
        struct line *line;
@@ -464,51 +594,56 @@ int line_get_config(char *name, struct line *lines, int num, char *str,
        dev = simple_strtoul(name, &end, 0);
        if((*end != '\0') || (end == name)){
                *error_out = "line_get_config failed to parse device number";
-               return(0);
+               return 0;
        }
 
        if((dev < 0) || (dev >= num)){
-               *error_out = "device number of of range";
-               return(0);
+               *error_out = "device number out of range";
+               return 0;
        }
 
        line = &lines[dev];
 
-       down(&line->sem);
+       spin_lock(&line->lock);
        if(!line->valid)
                CONFIG_CHUNK(str, size, n, "none", 1);
-       else if(line->count == 0)
+       else if(line->tty == NULL)
                CONFIG_CHUNK(str, size, n, line->init_str, 1);
        else n = chan_config_string(&line->chan_list, str, size, error_out);
-       up(&line->sem);
+       spin_unlock(&line->lock);
 
-       return(n);
+       return n;
 }
 
-int line_remove(struct line *lines, int num, char *str)
+int line_id(char **str, int *start_out, int *end_out)
 {
-       char config[sizeof("conxxxx=none\0")];
+       char *end;
+        int n;
 
-       sprintf(config, "%s=none", str);
-       return(!line_setup(lines, num, config, 0));
+       n = simple_strtoul(*str, &end, 0);
+       if((*end != '\0') || (end == *str))
+                return -1;
+
+        *str = end;
+        *start_out = n;
+        *end_out = n;
+        return n;
 }
 
-int line_write_room(struct tty_struct *tty)
+int line_remove(struct line *lines, unsigned int num, int n)
 {
-       struct line *dev = tty->driver_data;
-       int room;
+       int err;
+       char config[sizeof("conxxxx=none\0")];
 
-       if (tty->stopped)
-               return 0;
-       room = write_room(dev);
-       if (0 == room)
-               printk(KERN_DEBUG "%s: %s: no room left in buffer\n",
-                      __FUNCTION__,tty->name);
-       return room;
+       sprintf(config, "%d=none", n);
+       err = line_setup(lines, num, config);
+       if(err >= 0)
+               err = 0;
+       return err;
 }
 
 struct tty_driver *line_register_devfs(struct lines *set,
-                        struct line_driver *line_driver, 
+                        struct line_driver *line_driver,
                         struct tty_operations *ops, struct line *lines,
                         int nlines)
 {
@@ -537,7 +672,7 @@ struct tty_driver *line_register_devfs(struct lines *set,
        }
 
        for(i = 0; i < nlines; i++){
-               if(!lines[i].valid) 
+               if(!lines[i].valid)
                        tty_unregister_device(driver, i);
        }
 
@@ -545,7 +680,10 @@ struct tty_driver *line_register_devfs(struct lines *set,
        return driver;
 }
 
-void lines_init(struct line *lines, int nlines)
+static DEFINE_SPINLOCK(winch_handler_lock);
+static LIST_HEAD(winch_handlers);
+
+void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 {
        struct line *line;
        int i;
@@ -553,12 +691,17 @@ void lines_init(struct line *lines, int nlines)
        for(i = 0; i < nlines; i++){
                line = &lines[i];
                INIT_LIST_HEAD(&line->chan_list);
-               sema_init(&line->sem, 1);
-               if(line->init_str != NULL){
-                       line->init_str = uml_strdup(line->init_str);
-                       if(line->init_str == NULL)
-                               printk("lines_init - uml_strdup returned "
-                                      "NULL\n");
+
+               if(line->init_str == NULL)
+                       continue;
+
+               line->init_str = kstrdup(line->init_str, GFP_KERNEL);
+               if(line->init_str == NULL)
+                       printk("lines_init - kstrdup returned NULL\n");
+
+               if(parse_chan_pair(line->init_str, line, i, opts)){
+                       printk("parse_chan_pair failed for device %d\n", i);
+                       line->valid = 0;
                }
        }
 }
@@ -571,7 +714,7 @@ struct winch {
        struct tty_struct *tty;
 };
 
-irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
+static irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
 {
        struct winch *winch = data;
        struct tty_struct *tty;
@@ -587,7 +730,7 @@ irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
                                       "errno = %d\n", -err);
                                printk("fd %d is losing SIGWINCH support\n",
                                       winch->tty_fd);
-                               return(IRQ_HANDLED);
+                               return IRQ_HANDLED;
                        }
                        goto out;
                }
@@ -595,58 +738,85 @@ irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
        tty  = winch->tty;
        if (tty != NULL) {
                line = tty->driver_data;
-               chan_window_size(&line->chan_list,
-                                &tty->winsize.ws_row, 
+               chan_window_size(&line->chan_list, &tty->winsize.ws_row,
                                 &tty->winsize.ws_col);
                kill_pg(tty->pgrp, SIGWINCH, 1);
        }
  out:
        if(winch->fd != -1)
                reactivate_fd(winch->fd, WINCH_IRQ);
-       return(IRQ_HANDLED);
+       return IRQ_HANDLED;
 }
 
-DECLARE_MUTEX(winch_handler_sem);
-LIST_HEAD(winch_handlers);
-
 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
 {
        struct winch *winch;
 
-       down(&winch_handler_sem);
        winch = kmalloc(sizeof(*winch), GFP_KERNEL);
        if (winch == NULL) {
                printk("register_winch_irq - kmalloc failed\n");
-               goto out;
+               return;
        }
+
        *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
                                   .fd          = fd,
                                   .tty_fd      = tty_fd,
                                   .pid         = pid,
                                   .tty         = tty });
+
+       spin_lock(&winch_handler_lock);
        list_add(&winch->list, &winch_handlers);
-       if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt, 
-                         SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM, 
+       spin_unlock(&winch_handler_lock);
+
+       if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
+                         SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
                          "winch", winch) < 0)
                printk("register_winch_irq - failed to register IRQ\n");
- out:
-       up(&winch_handler_sem);
 }
 
-static void winch_cleanup(void)
+static void free_winch(struct winch *winch)
+{
+       list_del(&winch->list);
+
+       if(winch->pid != -1)
+               os_kill_process(winch->pid, 1);
+       if(winch->fd != -1)
+               os_close_file(winch->fd);
+
+       free_irq(WINCH_IRQ, winch);
+       kfree(winch);
+}
+
+static void unregister_winch(struct tty_struct *tty)
 {
        struct list_head *ele;
        struct winch *winch;
 
+       spin_lock(&winch_handler_lock);
+
        list_for_each(ele, &winch_handlers){
                winch = list_entry(ele, struct winch, list);
-               if(winch->fd != -1){
-                       deactivate_fd(winch->fd, WINCH_IRQ);
-                       os_close_file(winch->fd);
-               }
-               if(winch->pid != -1) 
-                       os_kill_process(winch->pid, 1);
+                if(winch->tty == tty){
+                       free_winch(winch);
+                       break;
+                }
+        }
+       spin_unlock(&winch_handler_lock);
+}
+
+static void winch_cleanup(void)
+{
+       struct list_head *ele, *next;
+       struct winch *winch;
+
+       spin_lock(&winch_handler_lock);
+
+       list_for_each_safe(ele, next, &winch_handlers){
+               winch = list_entry(ele, struct winch, list);
+               free_winch(winch);
        }
+
+       spin_unlock(&winch_handler_lock);
 }
 __uml_exitcall(winch_cleanup);
 
@@ -655,27 +825,17 @@ char *add_xterm_umid(char *base)
        char *umid, *title;
        int len;
 
-       umid = get_umid(1);
-       if(umid == NULL) return(base);
-       
+       umid = get_umid();
+       if(*umid == '\0')
+               return base;
+
        len = strlen(base) + strlen(" ()") + strlen(umid) + 1;
        title = kmalloc(len, GFP_KERNEL);
        if(title == NULL){
                printk("Failed to allocate buffer for xterm title\n");
-               return(base);
+               return base;
        }
 
        snprintf(title, len, "%s (%s)", base, umid);
-       return(title);
+       return title;
 }
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */