headers: remove sched.h from interrupt.h
[safe/jmp/linux-2.6] / arch / um / drivers / line.c
index 563ce76..cf8a97f 100644 (file)
@@ -1,26 +1,20 @@
 /*
- * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
+ * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */
 
-#include "linux/sched.h"
-#include "linux/slab.h"
-#include "linux/list.h"
+#include "linux/irqreturn.h"
 #include "linux/kd.h"
-#include "linux/interrupt.h"
-#include "asm/uaccess.h"
+#include "linux/sched.h"
 #include "chan_kern.h"
+#include "irq_kern.h"
 #include "irq_user.h"
-#include "line.h"
-#include "kern.h"
-#include "user_util.h"
 #include "kern_util.h"
 #include "os.h"
-#include "irq_kern.h"
 
 #define LINE_BUFSIZE 4096
 
-static irqreturn_t line_interrupt(int irq, void *data, struct pt_regs *unused)
+static irqreturn_t line_interrupt(int irq, void *data)
 {
        struct chan *chan = data;
        struct line *line = chan->line;
@@ -31,18 +25,19 @@ static irqreturn_t line_interrupt(int irq, void *data, struct pt_regs *unused)
        return IRQ_HANDLED;
 }
 
-static void line_timer_cb(void *arg)
+static void line_timer_cb(struct work_struct *work)
 {
-       struct line *line = arg;
+       struct line *line = container_of(work, struct line, task.work);
 
-       if(!line->throttled)
+       if (!line->throttled)
                chan_interrupt(&line->chan_list, &line->task, line->tty,
                               line->driver->read_irq);
 }
 
-/* Returns the free space inside the ring buffer of this line.
+/*
+ * Returns the free space inside the ring buffer of this line.
  *
- * Should be called while holding line->lock (this does not modify datas).
+ * Should be called while holding line->lock (this does not modify data).
  */
 static int write_room(struct line *line)
 {
@@ -55,7 +50,7 @@ static int write_room(struct line *line)
        n = line->head - line->tail;
 
        if (n <= 0)
-               n = LINE_BUFSIZE + n; /* The other case */
+               n += LINE_BUFSIZE; /* The other case */
        return n - 1;
 }
 
@@ -65,17 +60,10 @@ int line_write_room(struct tty_struct *tty)
        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;
 }
 
@@ -86,8 +74,7 @@ int line_chars_in_buffer(struct tty_struct *tty)
        int ret;
 
        spin_lock_irqsave(&line->lock, flags);
-
-       /*write_room subtracts 1 for the needed NULL, so we readd it.*/
+       /* 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);
 
@@ -107,11 +94,12 @@ static int buffer_data(struct line *line, const char *buf, int len)
 {
        int end, room;
 
-       if(line->buffer == NULL){
+       if (line->buffer == NULL) {
                line->buffer = kmalloc(LINE_BUFSIZE, GFP_ATOMIC);
                if (line->buffer == NULL) {
-                       printk("buffer_data - atomic allocation failed\n");
-                       return(0);
+                       printk(KERN_ERR "buffer_data - atomic allocation "
+                              "failed\n");
+                       return 0;
                }
                line->head = line->buffer;
                line->tail = line->buffer;
@@ -122,7 +110,7 @@ static int buffer_data(struct line *line, const char *buf, int len)
 
        end = line->buffer + LINE_BUFSIZE - line->tail;
 
-       if (len < end){
+       if (len < end) {
                memcpy(line->tail, buf, len);
                line->tail += len;
        }
@@ -162,8 +150,10 @@ static int flush_buffer(struct line *line)
                if (n < 0)
                        return n;
                if (n == count) {
-                       /* We have flushed from ->head to buffer end, now we
-                        * must flush only from the beginning to ->tail.*/
+                       /*
+                        * We have flushed from ->head to buffer end, now we
+                        * must flush only from the beginning to ->tail.
+                        */
                        line->head = line->buffer;
                } else {
                        line->head += n;
@@ -175,7 +165,7 @@ static int flush_buffer(struct line *line)
        n = write_chan(&line->chan_list, line->head, count,
                       line->driver->write_irq);
 
-       if(n < 0)
+       if (n < 0)
                return n;
 
        line->head += n;
@@ -188,47 +178,35 @@ void line_flush_buffer(struct tty_struct *tty)
        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.*/
+/*
+ * 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)
+int line_put_char(struct tty_struct *tty, unsigned char ch)
 {
-       line_write(tty, &ch, sizeof(ch));
+       return line_write(tty, &ch, sizeof(ch));
 }
 
 int line_write(struct tty_struct *tty, const unsigned char *buf, int len)
 {
        struct line *line = tty->driver_data;
        unsigned long flags;
-       int n, err, ret = 0;
-
-       if(tty->stopped)
-               return 0;
+       int n, ret = 0;
 
        spin_lock_irqsave(&line->lock, flags);
-       if (line->head != line->tail) {
+       if (line->head != line->tail)
                ret = buffer_data(line, buf, len);
-               err = flush_buffer(line);
-               if (err <= 0 && (err != -EAGAIN || !ret))
-                       ret = err;
-       } else {
+       else {
                n = write_chan(&line->chan_list, buf, len,
                               line->driver->write_irq);
                if (n < 0) {
@@ -246,7 +224,7 @@ out_up:
        return ret;
 }
 
-void line_set_termios(struct tty_struct *tty, struct termios * old)
+void line_set_termios(struct tty_struct *tty, struct ktermios * old)
 {
        /* nothing */
 }
@@ -258,17 +236,17 @@ static const struct {
 } tty_ioctls[] = {
        /* don't print these, they flood the log ... */
        { TCGETS,      NULL,       "TCGETS"      },
-        { TCSETS,      NULL,       "TCSETS"      },
-        { TCSETSW,     NULL,       "TCSETSW"     },
-        { TCFLSH,      NULL,       "TCFLSH"      },
-        { TCSBRK,      NULL,       "TCSBRK"      },
+       { TCSETS,      NULL,       "TCSETS"      },
+       { TCSETSW,     NULL,       "TCSETSW"     },
+       { TCFLSH,      NULL,       "TCFLSH"      },
+       { TCSBRK,      NULL,       "TCSBRK"      },
 
        /* general tty stuff */
-        { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
-        { TCGETA,      KERN_DEBUG, "TCGETA"      },
-        { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
-        { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
-        { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
+       { TCSETSF,     KERN_DEBUG, "TCSETSF"     },
+       { TCGETA,      KERN_DEBUG, "TCGETA"      },
+       { TIOCMGET,    KERN_DEBUG, "TIOCMGET"    },
+       { TCSBRKP,     KERN_DEBUG, "TCSBRKP"     },
+       { TIOCMSET,    KERN_DEBUG, "TIOCMSET"    },
 
        /* linux-specific ones */
        { TIOCLINUX,   KERN_INFO,  "TIOCLINUX"   },
@@ -298,6 +276,8 @@ int line_ioctl(struct tty_struct *tty, struct file * file,
        case TIOCGLTC:
        case TIOCSLTC:
 #endif
+       /* Note: these are out of date as we now have TCGETS2 etc but this
+          whole lot should probably go away */
        case TCGETS:
        case TCSETSF:
        case TCSETSW:
@@ -325,14 +305,9 @@ int line_ioctl(struct tty_struct *tty, struct file * file,
                for (i = 0; i < ARRAY_SIZE(tty_ioctls); i++)
                        if (cmd == tty_ioctls[i].cmd)
                                break;
-               if (i < ARRAY_SIZE(tty_ioctls)) {
-                       if (NULL != tty_ioctls[i].level)
-                               printk("%s%s: %s: ioctl %s called\n",
-                                      tty_ioctls[i].level, __FUNCTION__,
-                                      tty->name, tty_ioctls[i].name);
-               } else {
+               if (i == ARRAY_SIZE(tty_ioctls)) {
                        printk(KERN_ERR "%s: %s: unknown ioctl: 0x%x\n",
-                              __FUNCTION__, tty->name, cmd);
+                              __func__, tty->name, cmd);
                }
                ret = -ENOIOCTLCMD;
                break;
@@ -356,50 +331,41 @@ void line_unthrottle(struct tty_struct *tty)
        chan_interrupt(&line->chan_list, &line->task, tty,
                       line->driver->read_irq);
 
-       /* Maybe there is enough stuff pending that calling the interrupt
+       /*
+        * 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)
+       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)
+static irqreturn_t line_write_interrupt(int irq, void *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
-        * IRQF_DISABLED (see line_setup_irq).*/
+       /*
+        * Interrupts are disabled here because we registered the interrupt with
+        * IRQF_DISABLED (see line_setup_irq).
+        */
 
-       spin_lock_irq(&line->lock);
+       spin_lock(&line->lock);
        err = flush_buffer(line);
        if (err == 0) {
                return IRQ_NONE;
-       } else if(err < 0) {
+       } else if (err < 0) {
                line->head = line->buffer;
                line->tail = line->buffer;
        }
-       spin_unlock_irq(&line->lock);
+       spin_unlock(&line->lock);
 
-       if(tty == NULL)
+       if (tty == NULL)
                return IRQ_NONE;
 
-       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))
-               wake_up_interruptible(&tty->write_wait);
+       tty_wakeup(tty);
        return IRQ_HANDLED;
 }
 
@@ -422,42 +388,59 @@ int line_setup_irq(int fd, int input, int output, struct line *line, void *data)
        return err;
 }
 
+/*
+ * Normally, a driver like this can rely mostly on the tty layer
+ * locking, particularly when it comes to the driver structure.
+ * However, in this case, mconsole requests can come in "from the
+ * side", and race with opens and closes.
+ *
+ * mconsole config requests will want to be sure the device isn't in
+ * use, and get_config, open, and close will want a stable
+ * configuration.  The checking and modification of the configuration
+ * is done under a spinlock.  Checking whether the device is in use is
+ * line->tty->count > 1, also under the spinlock.
+ *
+ * tty->count serves to decide whether the device should be enabled or
+ * disabled on the host.  If it's equal to 1, then we are doing the
+ * first open or last close.  Otherwise, open and close just return.
+ */
+
 int line_open(struct line *lines, struct tty_struct *tty)
 {
-       struct line *line;
+       struct line *line = &lines[tty->index];
        int err = -ENODEV;
 
-       line = &lines[tty->index];
-       tty->driver_data = line;
+       spin_lock(&line->count_lock);
+       if (!line->valid)
+               goto out_unlock;
 
-       /* 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);
+       err = 0;
+       if (tty->count > 1)
+               goto out_unlock;
+
+       spin_unlock(&line->count_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);
+       err = enable_chan(line);
+       if (err)
+               return err;
 
-               if(!line->sigio){
-                       chan_enable_winch(&line->chan_list, tty);
-                       line->sigio = 1;
-               }
+       INIT_DELAYED_WORK(&line->task, line_timer_cb);
 
-               chan_window_size(&line->chan_list, &tty->winsize.ws_row,
-                                &tty->winsize.ws_col);
+       if (!line->sigio) {
+               chan_enable_winch(&line->chan_list, tty);
+               line->sigio = 1;
        }
 
-       err = 0;
-out:
-       spin_unlock(&line->lock);
+       chan_window_size(&line->chan_list, &tty->winsize.ws_row,
+                        &tty->winsize.ws_col);
+
+       return err;
+
+out_unlock:
+       spin_unlock(&line->count_lock);
        return err;
 }
 
@@ -467,25 +450,37 @@ void line_close(struct tty_struct *tty, struct file * filp)
 {
        struct line *line = tty->driver_data;
 
-       /* XXX: I assume this should be called in process context, not with
-         *  interrupts disabled!
-         */
-       spin_lock_irq(&line->lock);
+       /*
+        * If line_open fails (and tty->driver_data is never set),
+        * tty_open will call line_close.  So just return in this case.
+        */
+       if (line == NULL)
+               return;
 
        /* We ignore the error anyway! */
        flush_buffer(line);
 
-       if(tty->count == 1){
-               line->tty = NULL;
-               tty->driver_data = NULL;
+       spin_lock(&line->count_lock);
+       if (!line->valid)
+               goto out_unlock;
 
-               if(line->sigio){
-                       unregister_winch(tty);
-                       line->sigio = 0;
-               }
-        }
+       if (tty->count > 1)
+               goto out_unlock;
+
+       spin_unlock(&line->count_lock);
+
+       line->tty = NULL;
+       tty->driver_data = NULL;
+
+       if (line->sigio) {
+               unregister_winch(tty);
+               line->sigio = 0;
+       }
+
+       return;
 
-       spin_unlock_irq(&line->lock);
+out_unlock:
+       spin_unlock(&line->count_lock);
 }
 
 void close_lines(struct line *lines, int nlines)
@@ -496,91 +491,107 @@ void close_lines(struct line *lines, int nlines)
                close_chan(&lines[i].chan_list, 0);
 }
 
-/* Common setup code for both startup command line and mconsole initialization.
- * @lines contains the the array (of size @num) to modify;
+static int setup_one_line(struct line *lines, int n, char *init, int init_prio,
+                         char **error_out)
+{
+       struct line *line = &lines[n];
+       int err = -EINVAL;
+
+       spin_lock(&line->count_lock);
+
+       if (line->tty != NULL) {
+               *error_out = "Device is already open";
+               goto out;
+       }
+
+       if (line->init_pri <= init_prio) {
+               line->init_pri = init_prio;
+               if (!strcmp(init, "none"))
+                       line->valid = 0;
+               else {
+                       line->init_str = init;
+                       line->valid = 1;
+               }
+       }
+       err = 0;
+out:
+       spin_unlock(&line->count_lock);
+       return err;
+}
+
+/*
+ * Common setup code for both startup command line and mconsole initialization.
+ * @lines contains the array (of size @num) to modify;
  * @init is the setup string;
+ * @error_out is an error string in the case of failure;
  */
 
-int line_setup(struct line *lines, unsigned int num, char *init)
+int line_setup(struct line *lines, unsigned int num, char *init,
+              char **error_out)
 {
-       int i, n;
+       int i, n, err;
        char *end;
 
-       if(*init == '=') {
-               /* We said con=/ssl= instead of con#=, so we are configuring all
-                * consoles at once.*/
+       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",
-                              init);
-                       return 0;
+               if (*end != '=') {
+                       *error_out = "Couldn't parse device number";
+                       return -EINVAL;
                }
                init = end;
        }
        init++;
 
        if (n >= (signed int) num) {
-               printk("line_setup - %d out of range ((0 ... %d) allowed)\n",
-                      n, num - 1);
-               return 0;
+               *error_out = "Device number out of range";
+               return -EINVAL;
        }
-       else if (n >= 0){
-               if (lines[n].tty != NULL) {
-                       printk("line_setup - device %d is open\n", n);
-                       return 0;
-               }
-               if (lines[n].init_pri <= INIT_ONE){
-                       lines[n].init_pri = INIT_ONE;
-                       if (!strcmp(init, "none"))
-                               lines[n].valid = 0;
-                       else {
-                               lines[n].init_str = init;
-                               lines[n].valid = 1;
-                       }
-               }
+       else if (n >= 0) {
+               err = setup_one_line(lines, n, init, INIT_ONE, error_out);
+               if (err)
+                       return err;
        }
        else {
-               for(i = 0; i < num; i++){
-                       if(lines[i].init_pri <= INIT_ALL){
-                               lines[i].init_pri = INIT_ALL;
-                               if(!strcmp(init, "none")) lines[i].valid = 0;
-                               else {
-                                       lines[i].init_str = init;
-                                       lines[i].valid = 1;
-                               }
-                       }
+               for(i = 0; i < num; i++) {
+                       err = setup_one_line(lines, i, init, INIT_ALL,
+                                            error_out);
+                       if (err)
+                               return err;
                }
        }
        return n == -1 ? num : n;
 }
 
 int line_config(struct line *lines, unsigned int num, char *str,
-               const struct chan_opts *opts)
+               const struct chan_opts *opts, char **error_out)
 {
        struct line *line;
        char *new;
        int n;
 
-       if(*str == '='){
-               printk("line_config - can't configure all devices from "
-                      "mconsole\n");
-               return 1;
+       if (*str == '=') {
+               *error_out = "Can't configure all devices from mconsole";
+               return -EINVAL;
        }
 
        new = kstrdup(str, GFP_KERNEL);
-       if(new == NULL){
-               printk("line_config - kstrdup failed\n");
-               return 1;
+       if (new == NULL) {
+               *error_out = "Failed to allocate memory";
+               return -ENOMEM;
        }
-       n = line_setup(lines, num, new);
-       if(n < 0)
-               return 1;
+       n = line_setup(lines, num, new, error_out);
+       if (n < 0)
+               return n;
 
        line = &lines[n];
-       return parse_chan_pair(line->init_str, line, n, opts);
+       return parse_chan_pair(line->init_str, line, n, opts, error_out);
 }
 
 int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
@@ -591,25 +602,25 @@ int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
        int dev, n = 0;
 
        dev = simple_strtoul(name, &end, 0);
-       if((*end != '\0') || (end == name)){
+       if ((*end != '\0') || (end == name)) {
                *error_out = "line_get_config failed to parse device number";
                return 0;
        }
 
-       if((dev < 0) || (dev >= num)){
+       if ((dev < 0) || (dev >= num)) {
                *error_out = "device number out of range";
                return 0;
        }
 
        line = &lines[dev];
 
-       spin_lock(&line->lock);
-       if(!line->valid)
+       spin_lock(&line->count_lock);
+       if (!line->valid)
                CONFIG_CHUNK(str, size, n, "none", 1);
-       else if(line->tty == NULL)
+       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);
-       spin_unlock(&line->lock);
+       spin_unlock(&line->count_lock);
 
        return n;
 }
@@ -617,34 +628,33 @@ int line_get_config(char *name, struct line *lines, unsigned int num, char *str,
 int line_id(char **str, int *start_out, int *end_out)
 {
        char *end;
-        int n;
+       int n;
 
        n = simple_strtoul(*str, &end, 0);
-       if((*end != '\0') || (end == *str))
-                return -1;
+       if ((*end != '\0') || (end == *str))
+               return -1;
 
-        *str = end;
-        *start_out = n;
-        *end_out = n;
-        return n;
+       *str = end;
+       *start_out = n;
+       *end_out = n;
+       return n;
 }
 
-int line_remove(struct line *lines, unsigned int num, int n)
+int line_remove(struct line *lines, unsigned int num, int n, char **error_out)
 {
        int err;
        char config[sizeof("conxxxx=none\0")];
 
        sprintf(config, "%d=none", n);
-       err = line_setup(lines, num, config);
-       if(err >= 0)
+       err = line_setup(lines, num, config, error_out);
+       if (err >= 0)
                err = 0;
        return err;
 }
 
-struct tty_driver *line_register_devfs(struct lines *set,
-                        struct line_driver *line_driver,
-                        struct tty_operations *ops, struct line *lines,
-                        int nlines)
+struct tty_driver *register_lines(struct line_driver *line_driver,
+                                 const struct tty_operations *ops,
+                                 struct line *lines, int nlines)
 {
        int i;
        struct tty_driver *driver = alloc_tty_driver(nlines);
@@ -663,14 +673,14 @@ struct tty_driver *line_register_devfs(struct lines *set,
        tty_set_operations(driver, ops);
 
        if (tty_register_driver(driver)) {
-               printk("%s: can't register %s driver\n",
-                      __FUNCTION__,line_driver->name);
+               printk(KERN_ERR "register_lines : can't register %s driver\n",
+                      line_driver->name);
                put_tty_driver(driver);
                return NULL;
        }
 
-       for(i = 0; i < nlines; i++){
-               if(!lines[i].valid)
+       for(i = 0; i < nlines; i++) {
+               if (!lines[i].valid)
                        tty_unregister_device(driver, i);
        }
 
@@ -684,21 +694,23 @@ static LIST_HEAD(winch_handlers);
 void lines_init(struct line *lines, int nlines, struct chan_opts *opts)
 {
        struct line *line;
+       char *error;
        int i;
 
-       for(i = 0; i < nlines; i++){
+       for(i = 0; i < nlines; i++) {
                line = &lines[i];
                INIT_LIST_HEAD(&line->chan_list);
 
-               if(line->init_str == NULL)
+               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 (line->init_str == NULL)
+                       printk(KERN_ERR "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);
+               if (parse_chan_pair(line->init_str, line, i, opts, &error)) {
+                       printk(KERN_ERR "parse_chan_pair failed for "
+                              "device %d : %s\n", i, error);
                        line->valid = 0;
                }
        }
@@ -710,9 +722,25 @@ struct winch {
        int tty_fd;
        int pid;
        struct tty_struct *tty;
+       unsigned long stack;
 };
 
-static irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
+static void free_winch(struct winch *winch, int free_irq_ok)
+{
+       list_del(&winch->list);
+
+       if (winch->pid != -1)
+               os_kill_process(winch->pid, 1);
+       if (winch->fd != -1)
+               os_close_file(winch->fd);
+       if (winch->stack != 0)
+               free_stack(winch->stack, 0);
+       if (free_irq_ok)
+               free_irq(WINCH_IRQ, winch);
+       kfree(winch);
+}
+
+static irqreturn_t winch_interrupt(int irq, void *data)
 {
        struct winch *winch = data;
        struct tty_struct *tty;
@@ -720,69 +748,74 @@ static irqreturn_t winch_interrupt(int irq, void *data, struct pt_regs *unused)
        int err;
        char c;
 
-       if(winch->fd != -1){
+       if (winch->fd != -1) {
                err = generic_read(winch->fd, &c, NULL);
-               if(err < 0){
-                       if(err != -EAGAIN){
-                               printk("winch_interrupt : read failed, "
-                                      "errno = %d\n", -err);
-                               printk("fd %d is losing SIGWINCH support\n",
-                                      winch->tty_fd);
+               if (err < 0) {
+                       if (err != -EAGAIN) {
+                               printk(KERN_ERR "winch_interrupt : "
+                                      "read failed, errno = %d\n", -err);
+                               printk(KERN_ERR "fd %d is losing SIGWINCH "
+                                      "support\n", winch->tty_fd);
+                               free_winch(winch, 0);
                                return IRQ_HANDLED;
                        }
                        goto out;
                }
        }
-       tty  = winch->tty;
+       tty = winch->tty;
        if (tty != NULL) {
                line = tty->driver_data;
-               chan_window_size(&line->chan_list, &tty->winsize.ws_row,
-                                &tty->winsize.ws_col);
-               kill_pg(tty->pgrp, SIGWINCH, 1);
+               if (line != NULL) {
+                       chan_window_size(&line->chan_list, &tty->winsize.ws_row,
+                                        &tty->winsize.ws_col);
+                       kill_pgrp(tty->pgrp, SIGWINCH, 1);
+               }
        }
  out:
-       if(winch->fd != -1)
+       if (winch->fd != -1)
                reactivate_fd(winch->fd, WINCH_IRQ);
        return IRQ_HANDLED;
 }
 
-void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty)
+void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
+                       unsigned long stack)
 {
        struct winch *winch;
 
        winch = kmalloc(sizeof(*winch), GFP_KERNEL);
        if (winch == NULL) {
-               printk("register_winch_irq - kmalloc failed\n");
-               return;
+               printk(KERN_ERR "register_winch_irq - kmalloc failed\n");
+               goto cleanup;
        }
 
        *winch = ((struct winch) { .list        = LIST_HEAD_INIT(winch->list),
                                   .fd          = fd,
                                   .tty_fd      = tty_fd,
                                   .pid         = pid,
-                                  .tty         = tty });
+                                  .tty         = tty,
+                                  .stack       = stack });
+
+       if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
+                          IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
+                          "winch", winch) < 0) {
+               printk(KERN_ERR "register_winch_irq - failed to register "
+                      "IRQ\n");
+               goto out_free;
+       }
 
        spin_lock(&winch_handler_lock);
        list_add(&winch->list, &winch_handlers);
        spin_unlock(&winch_handler_lock);
 
-       if(um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
-                         IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
-                         "winch", winch) < 0)
-               printk("register_winch_irq - failed to register IRQ\n");
-}
-
-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);
+       return;
 
-       free_irq(WINCH_IRQ, winch);
+ out_free:
        kfree(winch);
+ cleanup:
+       os_kill_process(pid, 1);
+       os_close_file(fd);
+       if (stack != 0)
+               free_stack(stack, 0);
 }
 
 static void unregister_winch(struct tty_struct *tty)
@@ -792,13 +825,13 @@ static void unregister_winch(struct tty_struct *tty)
 
        spin_lock(&winch_handler_lock);
 
-       list_for_each(ele, &winch_handlers){
+       list_for_each(ele, &winch_handlers) {
                winch = list_entry(ele, struct winch, list);
-                if(winch->tty == tty){
-                       free_winch(winch);
+               if (winch->tty == tty) {
+                       free_winch(winch, 1);
                        break;
-                }
-        }
+               }
+       }
        spin_unlock(&winch_handler_lock);
 }
 
@@ -809,9 +842,9 @@ static void winch_cleanup(void)
 
        spin_lock(&winch_handler_lock);
 
-       list_for_each_safe(ele, next, &winch_handlers){
+       list_for_each_safe(ele, next, &winch_handlers) {
                winch = list_entry(ele, struct winch, list);
-               free_winch(winch);
+               free_winch(winch, 1);
        }
 
        spin_unlock(&winch_handler_lock);
@@ -824,13 +857,13 @@ char *add_xterm_umid(char *base)
        int len;
 
        umid = get_umid();
-       if(*umid == '\0')
+       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");
+       if (title == NULL) {
+               printk(KERN_ERR "Failed to allocate buffer for xterm title\n");
                return base;
        }