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path: root/drivers/input/evdev.c
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Diffstat (limited to 'drivers/input/evdev.c')
-rw-r--r--drivers/input/evdev.c54
1 files changed, 42 insertions, 12 deletions
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 2ee6c7a68bdc..054edf346e0b 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -10,7 +10,8 @@
#define EVDEV_MINOR_BASE 64
#define EVDEV_MINORS 32
-#define EVDEV_BUFFER_SIZE 64
+#define EVDEV_MIN_BUFFER_SIZE 64U
+#define EVDEV_BUF_PACKETS 8
#include <linux/poll.h>
#include <linux/sched.h>
@@ -23,7 +24,6 @@
#include "input-compat.h"
struct evdev {
- int exist;
int open;
int minor;
struct input_handle handle;
@@ -33,16 +33,18 @@ struct evdev {
spinlock_t client_lock; /* protects client_list */
struct mutex mutex;
struct device dev;
+ bool exist;
};
struct evdev_client {
- struct input_event buffer[EVDEV_BUFFER_SIZE];
int head;
int tail;
spinlock_t buffer_lock; /* protects access to buffer, head and tail */
struct fasync_struct *fasync;
struct evdev *evdev;
struct list_head node;
+ int bufsize;
+ struct input_event buffer[];
};
static struct evdev *evdev_table[EVDEV_MINORS];
@@ -52,11 +54,15 @@ static void evdev_pass_event(struct evdev_client *client,
struct input_event *event)
{
/*
- * Interrupts are disabled, just acquire the lock
+ * Interrupts are disabled, just acquire the lock.
+ * Make sure we don't leave with the client buffer
+ * "empty" by having client->head == client->tail.
*/
spin_lock(&client->buffer_lock);
- client->buffer[client->head++] = *event;
- client->head &= EVDEV_BUFFER_SIZE - 1;
+ do {
+ client->buffer[client->head++] = *event;
+ client->head &= client->bufsize - 1;
+ } while (client->head == client->tail);
spin_unlock(&client->buffer_lock);
if (event->type == EV_SYN)
@@ -242,11 +248,21 @@ static int evdev_release(struct inode *inode, struct file *file)
return 0;
}
+static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
+{
+ unsigned int n_events =
+ max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
+ EVDEV_MIN_BUFFER_SIZE);
+
+ return roundup_pow_of_two(n_events);
+}
+
static int evdev_open(struct inode *inode, struct file *file)
{
struct evdev *evdev;
struct evdev_client *client;
int i = iminor(inode) - EVDEV_MINOR_BASE;
+ unsigned int bufsize;
int error;
if (i >= EVDEV_MINORS)
@@ -263,12 +279,17 @@ static int evdev_open(struct inode *inode, struct file *file)
if (!evdev)
return -ENODEV;
- client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
+ bufsize = evdev_compute_buffer_size(evdev->handle.dev);
+
+ client = kzalloc(sizeof(struct evdev_client) +
+ bufsize * sizeof(struct input_event),
+ GFP_KERNEL);
if (!client) {
error = -ENOMEM;
goto err_put_evdev;
}
+ client->bufsize = bufsize;
spin_lock_init(&client->buffer_lock);
client->evdev = evdev;
evdev_attach_client(evdev, client);
@@ -334,7 +355,7 @@ static int evdev_fetch_next_event(struct evdev_client *client,
have_event = client->head != client->tail;
if (have_event) {
*event = client->buffer[client->tail++];
- client->tail &= EVDEV_BUFFER_SIZE - 1;
+ client->tail &= client->bufsize - 1;
}
spin_unlock_irq(&client->buffer_lock);
@@ -382,10 +403,15 @@ static unsigned int evdev_poll(struct file *file, poll_table *wait)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
+ unsigned int mask;
poll_wait(file, &evdev->wait, wait);
- return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
- (evdev->exist ? 0 : (POLLHUP | POLLERR));
+
+ mask = evdev->exist ? POLLOUT | POLLWRNORM : POLLHUP | POLLERR;
+ if (client->head != client->tail)
+ mask |= POLLIN | POLLRDNORM;
+
+ return mask;
}
#ifdef CONFIG_COMPAT
@@ -665,6 +691,10 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
sizeof(struct input_absinfo))))
return -EFAULT;
+ /* We can't change number of reserved MT slots */
+ if (t == ABS_MT_SLOT)
+ return -EINVAL;
+
/*
* Take event lock to ensure that we are not
* changing device parameters in the middle
@@ -768,7 +798,7 @@ static void evdev_remove_chrdev(struct evdev *evdev)
static void evdev_mark_dead(struct evdev *evdev)
{
mutex_lock(&evdev->mutex);
- evdev->exist = 0;
+ evdev->exist = false;
mutex_unlock(&evdev->mutex);
}
@@ -817,7 +847,7 @@ static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
init_waitqueue_head(&evdev->wait);
dev_set_name(&evdev->dev, "event%d", minor);
- evdev->exist = 1;
+ evdev->exist = true;
evdev->minor = minor;
evdev->handle.dev = input_get_device(dev);