Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756130Ab2BHDZm (ORCPT ); Tue, 7 Feb 2012 22:25:42 -0500 Received: from mail-pz0-f46.google.com ([209.85.210.46]:57006 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755937Ab2BHDZk (ORCPT ); Tue, 7 Feb 2012 22:25:40 -0500 From: Che-Liang Chiou To: linux-kernel@vger.kernel.org Cc: Dmitry Torokhov , linux-input@vger.kernel.org, Che-Liang Chiou Subject: [PATCH 2/5] Input: serio_raw - extract queue interface Date: Wed, 8 Feb 2012 11:24:54 +0800 Message-Id: <1328671497-20880-3-git-send-email-clchiou@chromium.org> X-Mailer: git-send-email 1.7.7.3 In-Reply-To: <1328671497-20880-1-git-send-email-clchiou@chromium.org> References: <1328671497-20880-1-git-send-email-clchiou@chromium.org> In-Reply-To: <1328084386-31110-1-git-send-email-clchiou@chromium.org> References: <1328084386-31110-1-git-send-email-clchiou@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7532 Lines: 271 serio_raw operates on an internal data queue that buffers input packets from device interrupt. As a queue is a generic data structure, it is useful for implementing debugging facilities. This patch extracts its interface in preparation for implementing debugging facilities. Signed-off-by: Che-Liang Chiou --- drivers/input/serio/serio_raw.c | 175 +++++++++++++++++++++++++++------------ 1 files changed, 121 insertions(+), 54 deletions(-) diff --git a/drivers/input/serio/serio_raw.c b/drivers/input/serio/serio_raw.c index 4494233..bc2a8c7 100644 --- a/drivers/input/serio/serio_raw.c +++ b/drivers/input/serio/serio_raw.c @@ -29,15 +29,19 @@ MODULE_DESCRIPTION(DRIVER_DESC); MODULE_LICENSE("GPL"); #define SERIO_RAW_QUEUE_LEN 64 -struct serio_raw { +struct queue { unsigned char queue[SERIO_RAW_QUEUE_LEN]; unsigned int tail, head; + wait_queue_head_t wait; +}; + +struct serio_raw { + struct queue queue; char name[16]; struct kref kref; struct serio *serio; struct miscdevice dev; - wait_queue_head_t wait; struct list_head client_list; struct list_head node; bool dead; @@ -53,6 +57,105 @@ static DEFINE_MUTEX(serio_raw_mutex); static LIST_HEAD(serio_raw_list); /********************************************************************* + * Interface with queue * + *********************************************************************/ + +static void queue_init(struct queue *queue) +{ + init_waitqueue_head(&queue->wait); +} + +static void queue_clear(struct queue *queue) +{ + queue->head = queue->tail = 0; +} + +static bool queue_available(struct queue *queue) +{ + return queue->head != queue->tail; +} + +static void queue_wakeup(struct queue *queue) +{ + wake_up_interruptible(&queue->wait); +} + +static bool queue_fetch_byte(struct queue *queue, char *c) +{ + bool available; + + available = queue_available(queue); + if (available) { + *c = queue->queue[queue->tail]; + queue->tail = (queue->tail + 1) % SERIO_RAW_QUEUE_LEN; + } + + return available; +} + +static ssize_t queue_read(struct queue *queue, + char __user *buffer, size_t count, bool *dead, bool nonblock, + bool (*fetch_byte)(struct queue *, char *)) +{ + char uninitialized_var(c); + ssize_t read = 0; + int retval; + + if (*dead) + return -ENODEV; + + if (!queue_available(queue) && nonblock) + return -EAGAIN; + + retval = wait_event_interruptible(queue->wait, + queue_available(queue) || *dead); + if (retval) + return retval; + + if (*dead) + return -ENODEV; + + while (read < count && fetch_byte(queue, &c)) { + if (put_user(c, buffer++)) { + retval = -EFAULT; + break; + } + read++; + } + + return read ?: retval; +} + +static bool queue_write_byte(struct queue *queue, char c) +{ + unsigned int head; + bool may_write; + + queue->queue[queue->head] = c; + head = (queue->head + 1) % SERIO_RAW_QUEUE_LEN; + may_write = head != queue->tail; + if (may_write) + queue->head = head; + + return may_write; +} + +static unsigned int queue_poll(struct queue *queue, struct file *file, + poll_table *wait, bool *dead) +{ + unsigned int mask; + + poll_wait(file, &queue->wait, wait); + + mask = *dead ? POLLHUP | POLLERR : POLLOUT | POLLWRNORM; + if (queue_available(queue)) + mask |= POLLIN | POLLRDNORM; + + return mask; +} + + +/********************************************************************* * Interface with userspace (file operations) * *********************************************************************/ @@ -141,21 +244,17 @@ static int serio_raw_release(struct inode *inode, struct file *file) return 0; } -static bool serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c) +static bool serio_raw_fetch_byte(struct queue *queue, char *c) { - bool empty; + struct serio_raw *serio_raw; + bool available; + serio_raw = container_of(queue, struct serio_raw, queue); serio_pause_rx(serio_raw->serio); - - empty = serio_raw->head == serio_raw->tail; - if (!empty) { - *c = serio_raw->queue[serio_raw->tail]; - serio_raw->tail = (serio_raw->tail + 1) % SERIO_RAW_QUEUE_LEN; - } - + available = queue_fetch_byte(queue, c); serio_continue_rx(serio_raw->serio); - return !empty; + return available; } static ssize_t serio_raw_read(struct file *file, char __user *buffer, @@ -163,33 +262,11 @@ static ssize_t serio_raw_read(struct file *file, char __user *buffer, { struct serio_raw_client *client = file->private_data; struct serio_raw *serio_raw = client->serio_raw; - char uninitialized_var(c); - ssize_t read = 0; - int retval; - - if (serio_raw->dead) - return -ENODEV; - - if (serio_raw->head == serio_raw->tail && (file->f_flags & O_NONBLOCK)) - return -EAGAIN; - - retval = wait_event_interruptible(serio_raw->wait, - serio_raw->head != serio_raw->tail || serio_raw->dead); - if (retval) - return retval; - - if (serio_raw->dead) - return -ENODEV; + struct queue *queue = &serio_raw->queue; - while (read < count && serio_raw_fetch_byte(serio_raw, &c)) { - if (put_user(c, buffer++)) { - retval = -EFAULT; - break; - } - read++; - } - - return read ?: retval; + return queue_read(queue, buffer, count, + &serio_raw->dead, file->f_flags & O_NONBLOCK, + serio_raw_fetch_byte); } static ssize_t serio_raw_write(struct file *file, const char __user *buffer, @@ -234,15 +311,9 @@ static unsigned int serio_raw_poll(struct file *file, poll_table *wait) { struct serio_raw_client *client = file->private_data; struct serio_raw *serio_raw = client->serio_raw; - unsigned int mask; - - poll_wait(file, &serio_raw->wait, wait); + struct queue *queue = &serio_raw->queue; - mask = serio_raw->dead ? POLLHUP | POLLERR : POLLOUT | POLLWRNORM; - if (serio_raw->head != serio_raw->tail) - mask |= POLLIN | POLLRDNORM; - - return mask; + return queue_poll(queue, file, wait, &serio_raw->dead); } static const struct file_operations serio_raw_fops = { @@ -266,16 +337,12 @@ static irqreturn_t serio_raw_interrupt(struct serio *serio, unsigned char data, { struct serio_raw *serio_raw = serio_get_drvdata(serio); struct serio_raw_client *client; - unsigned int head = serio_raw->head; /* we are holding serio->lock here so we are protected */ - serio_raw->queue[head] = data; - head = (head + 1) % SERIO_RAW_QUEUE_LEN; - if (likely(head != serio_raw->tail)) { - serio_raw->head = head; + if (queue_write_byte(&serio_raw->queue, data)) { list_for_each_entry(client, &serio_raw->client_list, node) kill_fasync(&client->fasync, SIGIO, POLL_IN); - wake_up_interruptible(&serio_raw->wait); + queue_wakeup(&serio_raw->queue); } return IRQ_HANDLED; @@ -297,7 +364,7 @@ static int serio_raw_connect(struct serio *serio, struct serio_driver *drv) "serio_raw%ld", (long)atomic_inc_return(&serio_raw_no) - 1); kref_init(&serio_raw->kref); INIT_LIST_HEAD(&serio_raw->client_list); - init_waitqueue_head(&serio_raw->wait); + queue_init(&serio_raw->queue); serio_raw->serio = serio; get_device(&serio->dev); @@ -378,7 +445,7 @@ static void serio_raw_hangup(struct serio_raw *serio_raw) kill_fasync(&client->fasync, SIGIO, POLL_HUP); serio_continue_rx(serio_raw->serio); - wake_up_interruptible(&serio_raw->wait); + queue_wakeup(&serio_raw->queue); } -- 1.7.7.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/