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-   -   UBUNTU: (evdev) Convert to dynamic event buffer (rev4) (http://www.linux-archive.org/ubuntu-kernel-team/384099-ubuntu-evdev-convert-dynamic-event-buffer-rev4.html)

"Henrik Rydberg" 06-10-2010 09:52 AM

UBUNTU: (evdev) Convert to dynamic event buffer (rev4)
 
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 | 23 +++++++++++++++++++----
1 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 7117589..463bf1b 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>
@@ -34,7 +34,8 @@ struct evdev {
struct mutex mutex;
struct device dev;
int head;
- struct input_event buffer[EVDEV_BUFFER_SIZE];
+ unsigned int bufsize;
+ struct input_event *buffer;
};

struct evdev_client {
@@ -75,7 +76,7 @@ static void evdev_event(struct input_handle *handle,

/* dev->event_lock held */
evdev->buffer[evdev->head] = event;
- evdev->head = (evdev->head + 1) & (EVDEV_BUFFER_SIZE - 1);
+ evdev->head = (evdev->head + 1) & (evdev->bufsize - 1);

rcu_read_lock();

@@ -122,6 +123,7 @@ static void evdev_free(struct device *dev)
struct evdev *evdev = container_of(dev, struct evdev, dev);

input_put_device(evdev->handle.dev);
+ kfree(evdev->buffer);
kfree(evdev);
}

@@ -340,7 +342,7 @@ static int evdev_fetch_next_event(struct evdev_client *client,
have_event = client->head != client->tail;
if (have_event) {
*event = evdev->buffer[client->tail++];
- client->tail &= EVDEV_BUFFER_SIZE - 1;
+ client->tail &= evdev->bufsize - 1;
}

spin_unlock_irq(&dev->event_lock);
@@ -793,6 +795,11 @@ static void evdev_cleanup(struct evdev *evdev)
}
}

+static int evdev_compute_buffer_size(struct input_dev *dev)
+{
+ return EVDEV_MIN_BUFFER_SIZE;
+}
+
/*
* Create new evdev device. Note that input core serializes calls
* to connect and disconnect so we don't need to lock evdev_table here.
@@ -837,6 +844,14 @@ static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
evdev->dev.release = evdev_free;
device_initialize(&evdev->dev);

+ evdev->bufsize = evdev_compute_buffer_size(dev);
+ evdev->buffer = kcalloc(evdev->bufsize, sizeof(struct input_event),
+ GFP_KERNEL);
+ if (!evdev->buffer) {
+ error = -ENOMEM;
+ goto err_free_evdev;
+ }
+
error = input_register_handle(&evdev->handle);
if (error)
goto err_free_evdev;
--
1.6.3.3


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