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Subject[patch 51/73] Input: joydev - implement proper locking
2.6.23-stable review patch.  If anyone has any objections, please let us know.
------------------
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

patch b126207ccdfe492fbc339c18d4898b1b5353fc6b in mainline.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/input/joydev.c | 745 ++++++++++++++++++++++++++++++++-----------------
1 file changed, 493 insertions(+), 252 deletions(-)

--- a/drivers/input/joydev.c
+++ b/drivers/input/joydev.c
@@ -43,6 +43,8 @@ struct joydev {
struct input_handle handle;
wait_queue_head_t wait;
struct list_head client_list;
+ spinlock_t client_lock; /* protects client_list */
+ struct mutex mutex;
struct device dev;

struct js_corr corr[ABS_MAX + 1];
@@ -61,31 +63,61 @@ struct joydev_client {
int head;
int tail;
int startup;
+ spinlock_t buffer_lock; /* protects access to buffer, head and tail */
struct fasync_struct *fasync;
struct joydev *joydev;
struct list_head node;
};

static struct joydev *joydev_table[JOYDEV_MINORS];
+static DEFINE_MUTEX(joydev_table_mutex);

static int joydev_correct(int value, struct js_corr *corr)
{
switch (corr->type) {
- case JS_CORR_NONE:
- break;
- case JS_CORR_BROKEN:
- value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
- ((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
- ((corr->coef[2] * (value - corr->coef[0])) >> 14);
- break;
- default:
- return 0;
+
+ case JS_CORR_NONE:
+ break;
+
+ case JS_CORR_BROKEN:
+ value = value > corr->coef[0] ? (value < corr->coef[1] ? 0 :
+ ((corr->coef[3] * (value - corr->coef[1])) >> 14)) :
+ ((corr->coef[2] * (value - corr->coef[0])) >> 14);
+ break;
+
+ default:
+ return 0;
}

return value < -32767 ? -32767 : (value > 32767 ? 32767 : value);
}

-static void joydev_event(struct input_handle *handle, unsigned int type, unsigned int code, int value)
+static void joydev_pass_event(struct joydev_client *client,
+ struct js_event *event)
+{
+ struct joydev *joydev = client->joydev;
+
+ /*
+ * IRQs already disabled, just acquire the lock
+ */
+ spin_lock(&client->buffer_lock);
+
+ client->buffer[client->head] = *event;
+
+ if (client->startup == joydev->nabs + joydev->nkey) {
+ client->head++;
+ client->head &= JOYDEV_BUFFER_SIZE - 1;
+ if (client->tail == client->head)
+ client->startup = 0;
+ }
+
+ spin_unlock(&client->buffer_lock);
+
+ kill_fasync(&client->fasync, SIGIO, POLL_IN);
+}
+
+static void joydev_event(struct input_handle *handle,
+ unsigned int type, unsigned int code, int value)
{
struct joydev *joydev = handle->private;
struct joydev_client *client;
@@ -93,39 +125,32 @@ static void joydev_event(struct input_ha

switch (type) {

- case EV_KEY:
- if (code < BTN_MISC || value == 2)
- return;
- event.type = JS_EVENT_BUTTON;
- event.number = joydev->keymap[code - BTN_MISC];
- event.value = value;
- break;
-
- case EV_ABS:
- event.type = JS_EVENT_AXIS;
- event.number = joydev->absmap[code];
- event.value = joydev_correct(value, joydev->corr + event.number);
- if (event.value == joydev->abs[event.number])
- return;
- joydev->abs[event.number] = event.value;
- break;
+ case EV_KEY:
+ if (code < BTN_MISC || value == 2)
+ return;
+ event.type = JS_EVENT_BUTTON;
+ event.number = joydev->keymap[code - BTN_MISC];
+ event.value = value;
+ break;

- default:
+ case EV_ABS:
+ event.type = JS_EVENT_AXIS;
+ event.number = joydev->absmap[code];
+ event.value = joydev_correct(value,
+ &joydev->corr[event.number]);
+ if (event.value == joydev->abs[event.number])
return;
+ joydev->abs[event.number] = event.value;
+ break;
+
+ default:
+ return;
}

event.time = jiffies_to_msecs(jiffies);

- list_for_each_entry(client, &joydev->client_list, node) {
-
- memcpy(client->buffer + client->head, &event, sizeof(struct js_event));
-
- if (client->startup == joydev->nabs + joydev->nkey)
- if (client->tail == (client->head = (client->head + 1) & (JOYDEV_BUFFER_SIZE - 1)))
- client->startup = 0;
-
- kill_fasync(&client->fasync, SIGIO, POLL_IN);
- }
+ list_for_each_entry_rcu(client, &joydev->client_list, node)
+ joydev_pass_event(client, &event);

wake_up_interruptible(&joydev->wait);
}
@@ -144,23 +169,85 @@ static void joydev_free(struct device *d
{
struct joydev *joydev = container_of(dev, struct joydev, dev);

- joydev_table[joydev->minor] = NULL;
kfree(joydev);
}

+static void joydev_attach_client(struct joydev *joydev,
+ struct joydev_client *client)
+{
+ spin_lock(&joydev->client_lock);
+ list_add_tail_rcu(&client->node, &joydev->client_list);
+ spin_unlock(&joydev->client_lock);
+ /*
+ * We don't use synchronize_rcu() here because read-side
+ * critical section is protected by a spinlock (dev->event_lock)
+ * instead of rcu_read_lock().
+ */
+ synchronize_sched();
+}
+
+static void joydev_detach_client(struct joydev *joydev,
+ struct joydev_client *client)
+{
+ spin_lock(&joydev->client_lock);
+ list_del_rcu(&client->node);
+ spin_unlock(&joydev->client_lock);
+ synchronize_sched();
+}
+
+static int joydev_open_device(struct joydev *joydev)
+{
+ int retval;
+
+ retval = mutex_lock_interruptible(&joydev->mutex);
+ if (retval)
+ return retval;
+
+ if (!joydev->exist)
+ retval = -ENODEV;
+ else if (!joydev->open++)
+ retval = input_open_device(&joydev->handle);
+
+ mutex_unlock(&joydev->mutex);
+ return retval;
+}
+
+static void joydev_close_device(struct joydev *joydev)
+{
+ mutex_lock(&joydev->mutex);
+
+ if (joydev->exist && !--joydev->open)
+ input_close_device(&joydev->handle);
+
+ mutex_unlock(&joydev->mutex);
+}
+
+/*
+ * Wake up users waiting for IO so they can disconnect from
+ * dead device.
+ */
+static void joydev_hangup(struct joydev *joydev)
+{
+ struct joydev_client *client;
+
+ spin_lock(&joydev->client_lock);
+ list_for_each_entry(client, &joydev->client_list, node)
+ kill_fasync(&client->fasync, SIGIO, POLL_HUP);
+ spin_unlock(&joydev->client_lock);
+
+ wake_up_interruptible(&joydev->wait);
+}
+
static int joydev_release(struct inode *inode, struct file *file)
{
struct joydev_client *client = file->private_data;
struct joydev *joydev = client->joydev;

joydev_fasync(-1, file, 0);
-
- list_del(&client->node);
+ joydev_detach_client(joydev, client);
kfree(client);

- if (!--joydev->open && joydev->exist)
- input_close_device(&joydev->handle);
-
+ joydev_close_device(joydev);
put_device(&joydev->dev);

return 0;
@@ -176,11 +263,16 @@ static int joydev_open(struct inode *ino
if (i >= JOYDEV_MINORS)
return -ENODEV;

+ error = mutex_lock_interruptible(&joydev_table_mutex);
+ if (error)
+ return error;
joydev = joydev_table[i];
- if (!joydev || !joydev->exist)
- return -ENODEV;
+ if (joydev)
+ get_device(&joydev->dev);
+ mutex_unlock(&joydev_table_mutex);

- get_device(&joydev->dev);
+ if (!joydev)
+ return -ENODEV;

client = kzalloc(sizeof(struct joydev_client), GFP_KERNEL);
if (!client) {
@@ -188,37 +280,129 @@ static int joydev_open(struct inode *ino
goto err_put_joydev;
}

+ spin_lock_init(&client->buffer_lock);
client->joydev = joydev;
- list_add_tail(&client->node, &joydev->client_list);
+ joydev_attach_client(joydev, client);

- if (!joydev->open++ && joydev->exist) {
- error = input_open_device(&joydev->handle);
- if (error)
- goto err_free_client;
- }
+ error = joydev_open_device(joydev);
+ if (error)
+ goto err_free_client;

file->private_data = client;
return 0;

err_free_client:
- list_del(&client->node);
+ joydev_detach_client(joydev, client);
kfree(client);
err_put_joydev:
put_device(&joydev->dev);
return error;
}

-static ssize_t joydev_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
+static int joydev_generate_startup_event(struct joydev_client *client,
+ struct input_dev *input,
+ struct js_event *event)
{
- return -EINVAL;
+ struct joydev *joydev = client->joydev;
+ int have_event;
+
+ spin_lock_irq(&client->buffer_lock);
+
+ have_event = client->startup < joydev->nabs + joydev->nkey;
+
+ if (have_event) {
+
+ event->time = jiffies_to_msecs(jiffies);
+ if (client->startup < joydev->nkey) {
+ event->type = JS_EVENT_BUTTON | JS_EVENT_INIT;
+ event->number = client->startup;
+ event->value = !!test_bit(joydev->keypam[event->number],
+ input->key);
+ } else {
+ event->type = JS_EVENT_AXIS | JS_EVENT_INIT;
+ event->number = client->startup - joydev->nkey;
+ event->value = joydev->abs[event->number];
+ }
+ client->startup++;
+ }
+
+ spin_unlock_irq(&client->buffer_lock);
+
+ return have_event;
+}
+
+static int joydev_fetch_next_event(struct joydev_client *client,
+ struct js_event *event)
+{
+ int have_event;
+
+ spin_lock_irq(&client->buffer_lock);
+
+ have_event = client->head != client->tail;
+ if (have_event) {
+ *event = client->buffer[client->tail++];
+ client->tail &= JOYDEV_BUFFER_SIZE - 1;
+ }
+
+ spin_unlock_irq(&client->buffer_lock);
+
+ return have_event;
}

-static ssize_t joydev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+/*
+ * Old joystick interface
+ */
+static ssize_t joydev_0x_read(struct joydev_client *client,
+ struct input_dev *input,
+ char __user *buf)
+{
+ struct joydev *joydev = client->joydev;
+ struct JS_DATA_TYPE data;
+ int i;
+
+ spin_lock_irq(&input->event_lock);
+
+ /*
+ * Get device state
+ */
+ for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
+ data.buttons |=
+ test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
+ data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
+ data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
+
+ /*
+ * Reset reader's event queue
+ */
+ spin_lock(&client->buffer_lock);
+ client->startup = 0;
+ client->tail = client->head;
+ spin_unlock(&client->buffer_lock);
+
+ spin_unlock_irq(&input->event_lock);
+
+ if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
+ return -EFAULT;
+
+ return sizeof(struct JS_DATA_TYPE);
+}
+
+static inline int joydev_data_pending(struct joydev_client *client)
+{
+ struct joydev *joydev = client->joydev;
+
+ return client->startup < joydev->nabs + joydev->nkey ||
+ client->head != client->tail;
+}
+
+static ssize_t joydev_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
{
struct joydev_client *client = file->private_data;
struct joydev *joydev = client->joydev;
struct input_dev *input = joydev->handle.dev;
- int retval = 0;
+ struct js_event event;
+ int retval;

if (!joydev->exist)
return -ENODEV;
@@ -226,68 +410,35 @@ static ssize_t joydev_read(struct file *
if (count < sizeof(struct js_event))
return -EINVAL;

- if (count == sizeof(struct JS_DATA_TYPE)) {
-
- struct JS_DATA_TYPE data;
- int i;
-
- for (data.buttons = i = 0; i < 32 && i < joydev->nkey; i++)
- data.buttons |= test_bit(joydev->keypam[i], input->key) ? (1 << i) : 0;
- data.x = (joydev->abs[0] / 256 + 128) >> joydev->glue.JS_CORR.x;
- data.y = (joydev->abs[1] / 256 + 128) >> joydev->glue.JS_CORR.y;
-
- if (copy_to_user(buf, &data, sizeof(struct JS_DATA_TYPE)))
- return -EFAULT;
-
- client->startup = 0;
- client->tail = client->head;
-
- return sizeof(struct JS_DATA_TYPE);
- }
+ if (count == sizeof(struct JS_DATA_TYPE))
+ return joydev_0x_read(client, input, buf);

- if (client->startup == joydev->nabs + joydev->nkey &&
- client->head == client->tail && (file->f_flags & O_NONBLOCK))
+ if (!joydev_data_pending(client) && (file->f_flags & O_NONBLOCK))
return -EAGAIN;

retval = wait_event_interruptible(joydev->wait,
- !joydev->exist ||
- client->startup < joydev->nabs + joydev->nkey ||
- client->head != client->tail);
+ !joydev->exist || joydev_data_pending(client));
if (retval)
return retval;

if (!joydev->exist)
return -ENODEV;

- while (client->startup < joydev->nabs + joydev->nkey && retval + sizeof(struct js_event) <= count) {
-
- struct js_event event;
-
- event.time = jiffies_to_msecs(jiffies);
-
- if (client->startup < joydev->nkey) {
- event.type = JS_EVENT_BUTTON | JS_EVENT_INIT;
- event.number = client->startup;
- event.value = !!test_bit(joydev->keypam[event.number], input->key);
- } else {
- event.type = JS_EVENT_AXIS | JS_EVENT_INIT;
- event.number = client->startup - joydev->nkey;
- event.value = joydev->abs[event.number];
- }
+ while (retval + sizeof(struct js_event) <= count &&
+ joydev_generate_startup_event(client, input, &event)) {

if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
return -EFAULT;

- client->startup++;
retval += sizeof(struct js_event);
}

- while (client->head != client->tail && retval + sizeof(struct js_event) <= count) {
+ while (retval + sizeof(struct js_event) <= count &&
+ joydev_fetch_next_event(client, &event)) {

- if (copy_to_user(buf + retval, client->buffer + client->tail, sizeof(struct js_event)))
+ if (copy_to_user(buf + retval, &event, sizeof(struct js_event)))
return -EFAULT;

- client->tail = (client->tail + 1) & (JOYDEV_BUFFER_SIZE - 1);
retval += sizeof(struct js_event);
}

@@ -301,126 +452,144 @@ static unsigned int joydev_poll(struct f
struct joydev *joydev = client->joydev;

poll_wait(file, &joydev->wait, wait);
- return ((client->head != client->tail || client->startup < joydev->nabs + joydev->nkey) ?
- (POLLIN | POLLRDNORM) : 0) | (joydev->exist ? 0 : (POLLHUP | POLLERR));
+ return (joydev_data_pending(client) ? (POLLIN | POLLRDNORM) : 0) |
+ (joydev->exist ? 0 : (POLLHUP | POLLERR));
}

-static int joydev_ioctl_common(struct joydev *joydev, unsigned int cmd, void __user *argp)
+static int joydev_ioctl_common(struct joydev *joydev,
+ unsigned int cmd, void __user *argp)
{
struct input_dev *dev = joydev->handle.dev;
int i, j;

switch (cmd) {

- case JS_SET_CAL:
- return copy_from_user(&joydev->glue.JS_CORR, argp,
+ case JS_SET_CAL:
+ return copy_from_user(&joydev->glue.JS_CORR, argp,
sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;

- case JS_GET_CAL:
- return copy_to_user(argp, &joydev->glue.JS_CORR,
+ case JS_GET_CAL:
+ return copy_to_user(argp, &joydev->glue.JS_CORR,
sizeof(joydev->glue.JS_CORR)) ? -EFAULT : 0;

- case JS_SET_TIMEOUT:
- return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
+ case JS_SET_TIMEOUT:
+ return get_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);

- case JS_GET_TIMEOUT:
- return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);
+ case JS_GET_TIMEOUT:
+ return put_user(joydev->glue.JS_TIMEOUT, (s32 __user *) argp);

- case JSIOCGVERSION:
- return put_user(JS_VERSION, (__u32 __user *) argp);
+ case JSIOCGVERSION:
+ return put_user(JS_VERSION, (__u32 __user *) argp);

- case JSIOCGAXES:
- return put_user(joydev->nabs, (__u8 __user *) argp);
-
- case JSIOCGBUTTONS:
- return put_user(joydev->nkey, (__u8 __user *) argp);
-
- case JSIOCSCORR:
- if (copy_from_user(joydev->corr, argp,
- sizeof(joydev->corr[0]) * joydev->nabs))
- return -EFAULT;
- for (i = 0; i < joydev->nabs; i++) {
- j = joydev->abspam[i];
- joydev->abs[i] = joydev_correct(dev->abs[j], joydev->corr + i);
- }
- return 0;
-
- case JSIOCGCORR:
- return copy_to_user(argp, joydev->corr,
- sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
+ case JSIOCGAXES:
+ return put_user(joydev->nabs, (__u8 __user *) argp);
+
+ case JSIOCGBUTTONS:
+ return put_user(joydev->nkey, (__u8 __user *) argp);
+
+ case JSIOCSCORR:
+ if (copy_from_user(joydev->corr, argp,
+ sizeof(joydev->corr[0]) * joydev->nabs))
+ return -EFAULT;
+
+ for (i = 0; i < joydev->nabs; i++) {
+ j = joydev->abspam[i];
+ joydev->abs[i] = joydev_correct(dev->abs[j],
+ &joydev->corr[i]);
+ }
+ return 0;

- case JSIOCSAXMAP:
- if (copy_from_user(joydev->abspam, argp, sizeof(__u8) * (ABS_MAX + 1)))
- return -EFAULT;
- for (i = 0; i < joydev->nabs; i++) {
- if (joydev->abspam[i] > ABS_MAX)
- return -EINVAL;
- joydev->absmap[joydev->abspam[i]] = i;
- }
- return 0;
-
- case JSIOCGAXMAP:
- return copy_to_user(argp, joydev->abspam,
- sizeof(__u8) * (ABS_MAX + 1)) ? -EFAULT : 0;
+ case JSIOCGCORR:
+ return copy_to_user(argp, joydev->corr,
+ sizeof(joydev->corr[0]) * joydev->nabs) ? -EFAULT : 0;
+
+ case JSIOCSAXMAP:
+ if (copy_from_user(joydev->abspam, argp,
+ sizeof(__u8) * (ABS_MAX + 1)))
+ return -EFAULT;
+
+ for (i = 0; i < joydev->nabs; i++) {
+ if (joydev->abspam[i] > ABS_MAX)
+ return -EINVAL;
+ joydev->absmap[joydev->abspam[i]] = i;
+ }
+ return 0;
+
+ case JSIOCGAXMAP:
+ return copy_to_user(argp, joydev->abspam,
+ sizeof(__u8) * (ABS_MAX + 1)) ? -EFAULT : 0;
+
+ case JSIOCSBTNMAP:
+ if (copy_from_user(joydev->keypam, argp,
+ sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)))
+ return -EFAULT;
+
+ for (i = 0; i < joydev->nkey; i++) {
+ if (joydev->keypam[i] > KEY_MAX ||
+ joydev->keypam[i] < BTN_MISC)
+ return -EINVAL;
+ joydev->keymap[joydev->keypam[i] - BTN_MISC] = i;
+ }

- case JSIOCSBTNMAP:
- if (copy_from_user(joydev->keypam, argp, sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)))
+ return 0;
+
+ case JSIOCGBTNMAP:
+ return copy_to_user(argp, joydev->keypam,
+ sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)) ? -EFAULT : 0;
+
+ default:
+ if ((cmd & ~IOCSIZE_MASK) == JSIOCGNAME(0)) {
+ int len;
+ if (!dev->name)
+ return 0;
+ len = strlen(dev->name) + 1;
+ if (len > _IOC_SIZE(cmd))
+ len = _IOC_SIZE(cmd);
+ if (copy_to_user(argp, dev->name, len))
return -EFAULT;
- for (i = 0; i < joydev->nkey; i++) {
- if (joydev->keypam[i] > KEY_MAX || joydev->keypam[i] < BTN_MISC)
- return -EINVAL;
- joydev->keymap[joydev->keypam[i] - BTN_MISC] = i;
- }
- return 0;
-
- case JSIOCGBTNMAP:
- return copy_to_user(argp, joydev->keypam,
- sizeof(__u16) * (KEY_MAX - BTN_MISC + 1)) ? -EFAULT : 0;
-
- default:
- if ((cmd & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT)) == JSIOCGNAME(0)) {
- int len;
- if (!dev->name)
- return 0;
- len = strlen(dev->name) + 1;
- if (len > _IOC_SIZE(cmd))
- len = _IOC_SIZE(cmd);
- if (copy_to_user(argp, dev->name, len))
- return -EFAULT;
- return len;
- }
+ return len;
+ }
}
return -EINVAL;
}

#ifdef CONFIG_COMPAT
-static long joydev_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+static long joydev_compat_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
{
struct joydev_client *client = file->private_data;
struct joydev *joydev = client->joydev;
void __user *argp = (void __user *)arg;
s32 tmp32;
struct JS_DATA_SAVE_TYPE_32 ds32;
- int err;
+ int retval;

- if (!joydev->exist)
- return -ENODEV;
+ retval = mutex_lock_interruptible(&joydev->mutex);
+ if (retval)
+ return retval;
+
+ if (!joydev->exist) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ switch (cmd) {

- switch(cmd) {
case JS_SET_TIMELIMIT:
- err = get_user(tmp32, (s32 __user *) arg);
- if (err == 0)
+ retval = get_user(tmp32, (s32 __user *) arg);
+ if (retval == 0)
joydev->glue.JS_TIMELIMIT = tmp32;
break;
+
case JS_GET_TIMELIMIT:
tmp32 = joydev->glue.JS_TIMELIMIT;
- err = put_user(tmp32, (s32 __user *) arg);
+ retval = put_user(tmp32, (s32 __user *) arg);
break;

case JS_SET_ALL:
- err = copy_from_user(&ds32, argp,
- sizeof(ds32)) ? -EFAULT : 0;
- if (err == 0) {
+ retval = copy_from_user(&ds32, argp,
+ sizeof(ds32)) ? -EFAULT : 0;
+ if (retval == 0) {
joydev->glue.JS_TIMEOUT = ds32.JS_TIMEOUT;
joydev->glue.BUSY = ds32.BUSY;
joydev->glue.JS_EXPIRETIME = ds32.JS_EXPIRETIME;
@@ -438,55 +607,119 @@ static long joydev_compat_ioctl(struct f
ds32.JS_SAVE = joydev->glue.JS_SAVE;
ds32.JS_CORR = joydev->glue.JS_CORR;

- err = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;
+ retval = copy_to_user(argp, &ds32, sizeof(ds32)) ? -EFAULT : 0;
break;

default:
- err = joydev_ioctl_common(joydev, cmd, argp);
+ retval = joydev_ioctl_common(joydev, cmd, argp);
+ break;
}
- return err;
+
+ out:
+ mutex_unlock(&joydev->mutex);
+ return retval;
}
#endif /* CONFIG_COMPAT */

-static int joydev_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
+static long joydev_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
{
struct joydev_client *client = file->private_data;
struct joydev *joydev = client->joydev;
void __user *argp = (void __user *)arg;
+ int retval;

- if (!joydev->exist)
- return -ENODEV;
+ retval = mutex_lock_interruptible(&joydev->mutex);
+ if (retval)
+ return retval;
+
+ if (!joydev->exist) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ switch (cmd) {
+
+ case JS_SET_TIMELIMIT:
+ retval = get_user(joydev->glue.JS_TIMELIMIT,
+ (long __user *) arg);
+ break;
+
+ case JS_GET_TIMELIMIT:
+ retval = put_user(joydev->glue.JS_TIMELIMIT,
+ (long __user *) arg);
+ break;
+
+ case JS_SET_ALL:
+ retval = copy_from_user(&joydev->glue, argp,
+ sizeof(joydev->glue)) ? -EFAULT: 0;
+ break;

- switch(cmd) {
- case JS_SET_TIMELIMIT:
- return get_user(joydev->glue.JS_TIMELIMIT, (long __user *) arg);
- case JS_GET_TIMELIMIT:
- return put_user(joydev->glue.JS_TIMELIMIT, (long __user *) arg);
- case JS_SET_ALL:
- return copy_from_user(&joydev->glue, argp,
- sizeof(joydev->glue)) ? -EFAULT : 0;
- case JS_GET_ALL:
- return copy_to_user(argp, &joydev->glue,
- sizeof(joydev->glue)) ? -EFAULT : 0;
- default:
- return joydev_ioctl_common(joydev, cmd, argp);
+ case JS_GET_ALL:
+ retval = copy_to_user(argp, &joydev->glue,
+ sizeof(joydev->glue)) ? -EFAULT : 0;
+ break;
+
+ default:
+ retval = joydev_ioctl_common(joydev, cmd, argp);
+ break;
}
+ out:
+ mutex_unlock(&joydev->mutex);
+ return retval;
}

static const struct file_operations joydev_fops = {
- .owner = THIS_MODULE,
- .read = joydev_read,
- .write = joydev_write,
- .poll = joydev_poll,
- .open = joydev_open,
- .release = joydev_release,
- .ioctl = joydev_ioctl,
+ .owner = THIS_MODULE,
+ .read = joydev_read,
+ .poll = joydev_poll,
+ .open = joydev_open,
+ .release = joydev_release,
+ .unlocked_ioctl = joydev_ioctl,
#ifdef CONFIG_COMPAT
- .compat_ioctl = joydev_compat_ioctl,
+ .compat_ioctl = joydev_compat_ioctl,
#endif
- .fasync = joydev_fasync,
+ .fasync = joydev_fasync,
};

+static int joydev_install_chrdev(struct joydev *joydev)
+{
+ joydev_table[joydev->minor] = joydev;
+ return 0;
+}
+
+static void joydev_remove_chrdev(struct joydev *joydev)
+{
+ mutex_lock(&joydev_table_mutex);
+ joydev_table[joydev->minor] = NULL;
+ mutex_unlock(&joydev_table_mutex);
+}
+
+/*
+ * Mark device non-existant. This disables writes, ioctls and
+ * prevents new users from opening the device. Already posted
+ * blocking reads will stay, however new ones will fail.
+ */
+static void joydev_mark_dead(struct joydev *joydev)
+{
+ mutex_lock(&joydev->mutex);
+ joydev->exist = 0;
+ mutex_unlock(&joydev->mutex);
+}
+
+static void joydev_cleanup(struct joydev *joydev)
+{
+ struct input_handle *handle = &joydev->handle;
+
+ joydev_mark_dead(joydev);
+ joydev_hangup(joydev);
+ joydev_remove_chrdev(joydev);
+
+ /* joydev is marked dead so noone else accesses joydev->open */
+ if (joydev->open)
+ input_close_device(handle);
+}
+
static int joydev_connect(struct input_handler *handler, struct input_dev *dev,
const struct input_device_id *id)
{
@@ -494,7 +727,10 @@ static int joydev_connect(struct input_h
int i, j, t, minor;
int error;

- for (minor = 0; minor < JOYDEV_MINORS && joydev_table[minor]; minor++);
+ for (minor = 0; minor < JOYDEV_MINORS; minor++)
+ if (!joydev_table[minor])
+ break;
+
if (minor == JOYDEV_MINORS) {
printk(KERN_ERR "joydev: no more free joydev devices\n");
return -ENFILE;
@@ -505,15 +741,19 @@ static int joydev_connect(struct input_h
return -ENOMEM;

INIT_LIST_HEAD(&joydev->client_list);
+ spin_lock_init(&joydev->client_lock);
+ mutex_init(&joydev->mutex);
init_waitqueue_head(&joydev->wait);

+ snprintf(joydev->name, sizeof(joydev->name), "js%d", minor);
+ joydev->exist = 1;
joydev->minor = minor;
+
joydev->exist = 1;
joydev->handle.dev = dev;
joydev->handle.name = joydev->name;
joydev->handle.handler = handler;
joydev->handle.private = joydev;
- snprintf(joydev->name, sizeof(joydev->name), "js%d", minor);

for (i = 0; i < ABS_MAX + 1; i++)
if (test_bit(i, dev->absbit)) {
@@ -545,67 +785,65 @@ static int joydev_connect(struct input_h
}
joydev->corr[i].type = JS_CORR_BROKEN;
joydev->corr[i].prec = dev->absfuzz[j];
- joydev->corr[i].coef[0] = (dev->absmax[j] + dev->absmin[j]) / 2 - dev->absflat[j];
- joydev->corr[i].coef[1] = (dev->absmax[j] + dev->absmin[j]) / 2 + dev->absflat[j];
- if (!(t = ((dev->absmax[j] - dev->absmin[j]) / 2 - 2 * dev->absflat[j])))
- continue;
- joydev->corr[i].coef[2] = (1 << 29) / t;
- joydev->corr[i].coef[3] = (1 << 29) / t;
+ joydev->corr[i].coef[0] =
+ (dev->absmax[j] + dev->absmin[j]) / 2 - dev->absflat[j];
+ joydev->corr[i].coef[1] =
+ (dev->absmax[j] + dev->absmin[j]) / 2 + dev->absflat[j];
+
+ t = (dev->absmax[j] - dev->absmin[j]) / 2 - 2 * dev->absflat[j];
+ if (t) {
+ joydev->corr[i].coef[2] = (1 << 29) / t;
+ joydev->corr[i].coef[3] = (1 << 29) / t;

- joydev->abs[i] = joydev_correct(dev->abs[j], joydev->corr + i);
+ joydev->abs[i] = joydev_correct(dev->abs[j],
+ joydev->corr + i);
+ }
}

- snprintf(joydev->dev.bus_id, sizeof(joydev->dev.bus_id),
- "js%d", minor);
+ strlcpy(joydev->dev.bus_id, joydev->name, sizeof(joydev->dev.bus_id));
+ joydev->dev.devt = MKDEV(INPUT_MAJOR, JOYDEV_MINOR_BASE + minor);
joydev->dev.class = &input_class;
joydev->dev.parent = &dev->dev;
- joydev->dev.devt = MKDEV(INPUT_MAJOR, JOYDEV_MINOR_BASE + minor);
joydev->dev.release = joydev_free;
device_initialize(&joydev->dev);

- joydev_table[minor] = joydev;
-
- error = device_add(&joydev->dev);
+ error = input_register_handle(&joydev->handle);
if (error)
goto err_free_joydev;

- error = input_register_handle(&joydev->handle);
+ error = joydev_install_chrdev(joydev);
if (error)
- goto err_delete_joydev;
+ goto err_unregister_handle;
+
+ error = device_add(&joydev->dev);
+ if (error)
+ goto err_cleanup_joydev;

return 0;

- err_delete_joydev:
- device_del(&joydev->dev);
+ err_cleanup_joydev:
+ joydev_cleanup(joydev);
+ err_unregister_handle:
+ input_unregister_handle(&joydev->handle);
err_free_joydev:
put_device(&joydev->dev);
return error;
}

-
static void joydev_disconnect(struct input_handle *handle)
{
struct joydev *joydev = handle->private;
- struct joydev_client *client;

- input_unregister_handle(handle);
device_del(&joydev->dev);
-
- joydev->exist = 0;
-
- if (joydev->open) {
- input_close_device(handle);
- list_for_each_entry(client, &joydev->client_list, node)
- kill_fasync(&client->fasync, SIGIO, POLL_HUP);
- wake_up_interruptible(&joydev->wait);
- }
-
+ joydev_cleanup(joydev);
+ input_unregister_handle(handle);
put_device(&joydev->dev);
}

static const struct input_device_id joydev_blacklist[] = {
{
- .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
+ .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+ INPUT_DEVICE_ID_MATCH_KEYBIT,
.evbit = { BIT(EV_KEY) },
.keybit = { [LONG(BTN_TOUCH)] = BIT(BTN_TOUCH) },
}, /* Avoid itouchpads, touchscreens and tablets */
@@ -614,17 +852,20 @@ static const struct input_device_id joyd

static const struct input_device_id joydev_ids[] = {
{
- .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_ABSBIT,
+ .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+ INPUT_DEVICE_ID_MATCH_ABSBIT,
.evbit = { BIT(EV_ABS) },
.absbit = { BIT(ABS_X) },
},
{
- .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_ABSBIT,
+ .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+ INPUT_DEVICE_ID_MATCH_ABSBIT,
.evbit = { BIT(EV_ABS) },
.absbit = { BIT(ABS_WHEEL) },
},
{
- .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_ABSBIT,
+ .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
+ INPUT_DEVICE_ID_MATCH_ABSBIT,
.evbit = { BIT(EV_ABS) },
.absbit = { BIT(ABS_THROTTLE) },
},
@@ -634,14 +875,14 @@ static const struct input_device_id joyd
MODULE_DEVICE_TABLE(input, joydev_ids);

static struct input_handler joydev_handler = {
- .event = joydev_event,
- .connect = joydev_connect,
- .disconnect = joydev_disconnect,
- .fops = &joydev_fops,
- .minor = JOYDEV_MINOR_BASE,
- .name = "joydev",
- .id_table = joydev_ids,
- .blacklist = joydev_blacklist,
+ .event = joydev_event,
+ .connect = joydev_connect,
+ .disconnect = joydev_disconnect,
+ .fops = &joydev_fops,
+ .minor = JOYDEV_MINOR_BASE,
+ .name = "joydev",
+ .id_table = joydev_ids,
+ .blacklist = joydev_blacklist,
};

static int __init joydev_init(void)
--


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