The patch titled
input: evdev - implement proper locking
has been removed from the -mm tree. Its filename was
input-evdev-implement-proper-locking.patch
This patch was dropped because it had testing failures
------------------------------------------------------
Subject: input: evdev - implement proper locking
From: Dmitry Torokhov <dtor@xxxxxxxxxxxxx>
Input: evdev - implement proper locking
Signed-off-by: Dmitry Torokhov <dtor@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/input/evdev.c | 353 ++++++++++++++++++++++++++++------------
1 files changed, 255 insertions(+), 98 deletions(-)
diff -puN drivers/input/evdev.c~input-evdev-implement-proper-locking drivers/input/evdev.c
--- a/drivers/input/evdev.c~input-evdev-implement-proper-locking
+++ a/drivers/input/evdev.c
@@ -31,6 +31,8 @@ struct evdev {
wait_queue_head_t wait;
struct evdev_client *grab;
struct list_head client_list;
+ spinlock_t client_lock;
+ struct mutex mutex;
struct device dev;
};
@@ -38,39 +40,48 @@ struct evdev_client {
struct input_event buffer[EVDEV_BUFFER_SIZE];
int head;
int tail;
+ spinlock_t buffer_lock;
struct fasync_struct *fasync;
struct evdev *evdev;
struct list_head node;
};
static struct evdev *evdev_table[EVDEV_MINORS];
+static DEFINE_MUTEX(evdev_table_mutex);
+
+static void evdev_pass_event(struct evdev_client *client, struct input_event *event)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&client->buffer_lock, flags);
+ client->buffer[client->head++] = *event;
+ client->head &= EVDEV_BUFFER_SIZE - 1;
+ spin_unlock_irqrestore(&client->buffer_lock, flags);
+
+ kill_fasync(&client->fasync, SIGIO, POLL_IN);
+}
static void evdev_event(struct input_handle *handle, unsigned int type, unsigned int code, int value)
{
struct evdev *evdev = handle->private;
struct evdev_client *client;
+ struct input_event event;
- if (evdev->grab) {
- client = evdev->grab;
-
- do_gettimeofday(&client->buffer[client->head].time);
- client->buffer[client->head].type = type;
- client->buffer[client->head].code = code;
- client->buffer[client->head].value = value;
- client->head = (client->head + 1) & (EVDEV_BUFFER_SIZE - 1);
-
- kill_fasync(&client->fasync, SIGIO, POLL_IN);
- } else
- list_for_each_entry(client, &evdev->client_list, node) {
-
- do_gettimeofday(&client->buffer[client->head].time);
- client->buffer[client->head].type = type;
- client->buffer[client->head].code = code;
- client->buffer[client->head].value = value;
- client->head = (client->head + 1) & (EVDEV_BUFFER_SIZE - 1);
+ do_gettimeofday(&event.time);
+ event.type = type;
+ event.code = code;
+ event.value = value;
+
+ rcu_read_lock();
+
+ client = rcu_dereference(evdev->grab);
+ if (client)
+ evdev_pass_event(client, &event);
+ else
+ list_for_each_entry_rcu(client, &evdev->client_list, node)
+ evdev_pass_event(client, &event);
- kill_fasync(&client->fasync, SIGIO, POLL_IN);
- }
+ rcu_read_unlock();
wake_up_interruptible(&evdev->wait);
}
@@ -89,33 +100,98 @@ static int evdev_flush(struct file *file
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
+ int retval;
+
+
+ retval = mutex_lock_interruptible(&evdev->mutex);
+ if (retval)
+ return retval;
if (!evdev->exist)
- return -ENODEV;
+ retval = -ENODEV;
+ else
+ retval = input_flush_device(&evdev->handle, file);
- return input_flush_device(&evdev->handle, file);
+ mutex_unlock(&evdev->mutex);
+ return retval;
}
static void evdev_free(struct device *dev)
{
struct evdev *evdev = container_of(dev, struct evdev, dev);
- evdev_table[evdev->minor] = NULL;
kfree(evdev);
}
+static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
+{
+ int error;
+
+ if (evdev->grab)
+ return -EBUSY;
+
+ error = input_grab_device(&evdev->handle);
+ if (error)
+ return error;
+
+ rcu_assign_pointer(evdev->grab, client);
+ synchronize_rcu();
+
+ return 0;
+}
+
+static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
+{
+ if (evdev->grab != client)
+ return -EINVAL;
+
+ rcu_assign_pointer(evdev->grab, NULL);
+ synchronize_rcu();
+ input_release_device(&evdev->handle);
+
+ return 0;
+}
+
+static void evdev_attach_client(struct evdev *evdev, struct evdev_client *client)
+{
+ spin_lock(&evdev->client_lock);
+ list_add_tail_rcu(&client->node, &evdev->client_list);
+ spin_unlock(&evdev->client_lock);
+ synchronize_rcu();
+}
+
+static void evdev_detach_client(struct evdev *evdev, struct evdev_client *client)
+{
+ spin_lock(&evdev->client_lock);
+ list_del_rcu(&client->node);
+ spin_unlock(&evdev->client_lock);
+ synchronize_rcu();
+}
+
+static void evdev_hangup(struct evdev *evdev)
+{
+ struct evdev_client *client;
+
+ wake_up_interruptible(&evdev->wait);
+
+ spin_lock(&evdev->client_lock);
+ list_for_each_entry(client, &evdev->client_list, node)
+ kill_fasync(&client->fasync, SIGIO, POLL_HUP);
+ spin_unlock(&evdev->client_lock);
+}
+
static int evdev_release(struct inode *inode, struct file *file)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
- if (evdev->grab == client) {
- input_release_device(&evdev->handle);
- evdev->grab = NULL;
- }
+ mutex_lock(&evdev->mutex);
+ if (evdev->grab == client)
+ evdev_ungrab(evdev, client);
+ mutex_unlock(&evdev->mutex);
evdev_fasync(-1, file, 0);
- list_del(&client->node);
+ evdev_detach_client(evdev, client);
kfree(client);
if (!--evdev->open && evdev->exist)
@@ -126,47 +202,53 @@ static int evdev_release(struct inode *i
return 0;
}
-static int evdev_open(struct inode *inode, struct file *file)
+static int evdev_new_client(struct evdev *evdev, struct file *file)
{
struct evdev_client *client;
- struct evdev *evdev;
- int i = iminor(inode) - EVDEV_MINOR_BASE;
int error;
- if (i >= EVDEV_MINORS)
- return -ENODEV;
-
- evdev = evdev_table[i];
-
- if (!evdev || !evdev->exist)
+ if (!evdev)
return -ENODEV;
- get_device(&evdev->dev);
-
client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
- if (!client) {
- error = -ENOMEM;
- goto err_put_evdev;
- }
+ if (!client)
+ return -ENOMEM;
+ spin_lock_init(&client->buffer_lock);
client->evdev = evdev;
- list_add_tail(&client->node, &evdev->client_list);
+ evdev_attach_client(evdev, client);
if (!evdev->open++ && evdev->exist) {
error = input_open_device(&evdev->handle);
- if (error)
- goto err_free_client;
+ if (error) {
+ evdev_detach_client(evdev, client);
+ kfree(client);
+ return error;
+ }
}
+ get_device(&evdev->dev);
file->private_data = client;
return 0;
+}
- err_free_client:
- list_del(&client->node);
- kfree(client);
- err_put_evdev:
- put_device(&evdev->dev);
- return error;
+static int evdev_open(struct inode *inode, struct file *file)
+{
+ int i = iminor(inode) - EVDEV_MINOR_BASE;
+ int retval;
+
+ if (i >= EVDEV_MINORS)
+ return -ENODEV;
+
+ retval = mutex_lock_interruptible(&evdev_table_mutex);
+ if (retval)
+ return retval;
+
+ retval = evdev_new_client(evdev_table[i], file);
+
+ mutex_unlock(&evdev_table_mutex);
+
+ return retval;
}
#ifdef CONFIG_COMPAT
@@ -272,26 +354,56 @@ static ssize_t evdev_write(struct file *
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
struct input_event event;
- int retval = 0;
+ int retval;
- if (!evdev->exist)
- return -ENODEV;
+ retval = mutex_lock_interruptible(&evdev->mutex);
+ if (retval)
+ return retval;
+
+ if (!evdev->exist) {
+ retval = -ENODEV;
+ goto out;
+ }
while (retval < count) {
- if (evdev_event_from_user(buffer + retval, &event))
- return -EFAULT;
+ if (evdev_event_from_user(buffer + retval, &event)) {
+ retval = -EFAULT;
+ goto out;
+ }
+
input_inject_event(&evdev->handle, event.type, event.code, event.value);
retval += evdev_event_size();
}
+ out:
+ mutex_unlock(&evdev->mutex);
return retval;
}
+static int evdev_fetch_next_event(struct evdev_client *client,
+ struct input_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 &= EVDEV_BUFFER_SIZE - 1;
+ }
+
+ spin_unlock_irq(&client->buffer_lock);
+
+ return have_event;
+}
+
static ssize_t evdev_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
+ struct input_event event;
int retval;
if (count < evdev_event_size())
@@ -308,14 +420,12 @@ static ssize_t evdev_read(struct file *f
if (!evdev->exist)
return -ENODEV;
- while (client->head != client->tail && retval + evdev_event_size() <= count) {
-
- struct input_event *event = (struct input_event *) client->buffer + client->tail;
+ while (retval + evdev_event_size() <= count &&
+ evdev_fetch_next_event(client, &event)) {
- if (evdev_event_to_user(buffer + retval, event))
+ if (evdev_event_to_user(buffer + retval, &event))
return -EFAULT;
- client->tail = (client->tail + 1) & (EVDEV_BUFFER_SIZE - 1);
retval += evdev_event_size();
}
@@ -410,8 +520,8 @@ static int str_to_user(const char *str,
return copy_to_user(p, str, len) ? -EFAULT : len;
}
-static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
- void __user *p, int compat_mode)
+static long evdev_do_ioctl(struct file *file, unsigned int cmd,
+ void __user *p, int compat_mode)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
@@ -422,9 +532,6 @@ static long evdev_ioctl_handler(struct f
int i, t, u, v;
int error;
- if (!evdev->exist)
- return -ENODEV;
-
switch (cmd) {
case EVIOCGVERSION:
@@ -497,20 +604,10 @@ static long evdev_ioctl_handler(struct f
return 0;
case EVIOCGRAB:
- if (p) {
- if (evdev->grab)
- return -EBUSY;
- if (input_grab_device(&evdev->handle))
- return -EBUSY;
- evdev->grab = client;
- return 0;
- } else {
- if (evdev->grab != client)
- return -EINVAL;
- input_release_device(&evdev->handle);
- evdev->grab = NULL;
- return 0;
- }
+ if (p)
+ return evdev_grab(evdev, client);
+ else
+ return evdev_ungrab(evdev, client);
default:
@@ -604,6 +701,29 @@ static long evdev_ioctl_handler(struct f
return -EINVAL;
}
+static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
+ void __user *p, int compat_mode)
+{
+ struct evdev_client *client = file->private_data;
+ struct evdev *evdev = client->evdev;
+ int retval;
+
+ retval = mutex_lock_interruptible(&evdev->mutex);
+ if (retval)
+ return retval;
+
+ if (!evdev->exist) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ retval = evdev_do_ioctl(file, cmd, p, compat_mode);
+
+ out:
+ mutex_unlock(&evdev->mutex);
+ return retval;
+}
+
static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
@@ -631,47 +751,81 @@ static const struct file_operations evde
.flush = evdev_flush
};
-static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
- const struct input_device_id *id)
+static int evdev_install_chrdev(struct evdev *evdev)
{
- struct evdev *evdev;
int minor;
- int error;
+ int retval;
+
+ retval = mutex_lock_interruptible(&evdev_table_mutex);
+ if (retval)
+ return retval;
for (minor = 0; minor < EVDEV_MINORS && evdev_table[minor]; minor++);
if (minor == EVDEV_MINORS) {
printk(KERN_ERR "evdev: no more free evdev devices\n");
- return -ENFILE;
+ retval = -ENFILE;
+ goto out;
}
+ snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
+ evdev->minor = minor;
+ strlcpy(evdev->dev.bus_id, evdev->name, sizeof(evdev->dev.bus_id));
+ evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
+
+ evdev_table[minor] = evdev;
+
+ out:
+ mutex_unlock(&evdev_table_mutex);
+ return retval;
+}
+
+static void evdev_remove_chrdev(struct evdev *evdev)
+{
+ mutex_lock(&evdev_table_mutex);
+ evdev_table[evdev->minor] = NULL;
+ mutex_unlock(&evdev_table_mutex);
+}
+
+static void evdev_mark_dead(struct evdev *evdev)
+{
+ mutex_lock(&evdev->mutex);
+ evdev->exist = 0;
+ mutex_unlock(&evdev->mutex);
+}
+
+static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
+ const struct input_device_id *id)
+{
+ struct evdev *evdev;
+ int error;
+
evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
if (!evdev)
return -ENOMEM;
INIT_LIST_HEAD(&evdev->client_list);
+ spin_lock_init(&evdev->client_lock);
+ mutex_init(&evdev->mutex);
init_waitqueue_head(&evdev->wait);
evdev->exist = 1;
- evdev->minor = minor;
evdev->handle.dev = dev;
evdev->handle.name = evdev->name;
evdev->handle.handler = handler;
evdev->handle.private = evdev;
- snprintf(evdev->name, sizeof(evdev->name), "event%d", minor);
- snprintf(evdev->dev.bus_id, sizeof(evdev->dev.bus_id),
- "event%d", minor);
evdev->dev.class = &input_class;
evdev->dev.parent = &dev->dev;
- evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
evdev->dev.release = evdev_free;
device_initialize(&evdev->dev);
- evdev_table[minor] = evdev;
+ error = evdev_install_chrdev(evdev);
+ if (error)
+ goto err_free_evdev;
error = device_add(&evdev->dev);
if (error)
- goto err_free_evdev;
+ goto err_remove_chrdev;
error = input_register_handle(&evdev->handle);
if (error)
@@ -681,6 +835,10 @@ static int evdev_connect(struct input_ha
err_delete_evdev:
device_del(&evdev->dev);
+ err_remove_chrdev:
+ evdev_remove_chrdev(evdev);
+ evdev_mark_dead(evdev);
+ evdev_hangup(evdev);
err_free_evdev:
put_device(&evdev->dev);
return error;
@@ -689,19 +847,18 @@ static int evdev_connect(struct input_ha
static void evdev_disconnect(struct input_handle *handle)
{
struct evdev *evdev = handle->private;
- struct evdev_client *client;
+
+ evdev_remove_chrdev(evdev);
input_unregister_handle(handle);
device_del(&evdev->dev);
- evdev->exist = 0;
+ evdev_mark_dead(evdev);
+ evdev_hangup(evdev);
if (evdev->open) {
input_flush_device(handle, NULL);
input_close_device(handle);
- wake_up_interruptible(&evdev->wait);
- list_for_each_entry(client, &evdev->client_list, node)
- kill_fasync(&client->fasync, SIGIO, POLL_HUP);
}
put_device(&evdev->dev);
_
Patches currently in -mm which might be from dtor@xxxxxxxxxxxxx are
git-input.patch
input-evdev-implement-proper-locking.patch
input-rfkill-add-support-for-input-key-to-control-wireless-radio-fixes.patch
input-rfkill-add-support-for-input-key-to-control-wireless-radio-fixes-fix.patch
-
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