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Subject[PATCH 1/5] input: evdev: Convert to dynamic event buffer (rev5)
Date
Allocate the event buffer dynamically, and prepare to compute the
buffer size in a separate function. This patch defines the size
computation to be identical to the current code, and does not contain
any logical changes.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
---
drivers/input/evdev.c | 25 +++++++++++++++++++++----
1 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 2ee6c7a..5d84e59 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -10,7 +10,7 @@

#define EVDEV_MINOR_BASE 64
#define EVDEV_MINORS 32
-#define EVDEV_BUFFER_SIZE 64
+#define EVDEV_MIN_BUFFER_SIZE 64

#include <linux/poll.h>
#include <linux/sched.h>
@@ -36,7 +36,8 @@ struct evdev {
};

struct evdev_client {
- struct input_event buffer[EVDEV_BUFFER_SIZE];
+ struct input_event *buffer;
+ int bufsize;
int head;
int tail;
spinlock_t buffer_lock; /* protects access to buffer, head and tail */
@@ -48,6 +49,11 @@ struct evdev_client {
static struct evdev *evdev_table[EVDEV_MINORS];
static DEFINE_MUTEX(evdev_table_mutex);

+static int evdev_compute_buffer_size(struct input_dev *dev)
+{
+ return EVDEV_MIN_BUFFER_SIZE;
+}
+
static void evdev_pass_event(struct evdev_client *client,
struct input_event *event)
{
@@ -56,7 +62,7 @@ static void evdev_pass_event(struct evdev_client *client,
*/
spin_lock(&client->buffer_lock);
client->buffer[client->head++] = *event;
- client->head &= EVDEV_BUFFER_SIZE - 1;
+ client->head &= client->bufsize - 1;
spin_unlock(&client->buffer_lock);

if (event->type == EV_SYN)
@@ -234,6 +240,7 @@ static int evdev_release(struct inode *inode, struct file *file)
mutex_unlock(&evdev->mutex);

evdev_detach_client(evdev, client);
+ kfree(client->buffer);
kfree(client);

evdev_close_device(evdev);
@@ -269,6 +276,14 @@ static int evdev_open(struct inode *inode, struct file *file)
goto err_put_evdev;
}

+ client->bufsize = evdev_compute_buffer_size(evdev->handle.dev);
+ client->buffer = kcalloc(client->bufsize, sizeof(struct input_event),
+ GFP_KERNEL);
+ if (!client->buffer) {
+ error = -ENOMEM;
+ goto err_free_memory;
+ }
+
spin_lock_init(&client->buffer_lock);
client->evdev = evdev;
evdev_attach_client(evdev, client);
@@ -284,6 +299,8 @@ static int evdev_open(struct inode *inode, struct file *file)

err_free_client:
evdev_detach_client(evdev, client);
+ kfree(client->buffer);
+ err_free_memory:
kfree(client);
err_put_evdev:
put_device(&evdev->dev);
@@ -334,7 +351,7 @@ 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);
--
1.6.3.3


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