greybus: loopback: convert sample report interface to debugfs
Greg previously suggested switching over to debugfs instead of a char
interface to report raw samples to user-space. At the time we agreed not
to go for that change. However later patches in this series are made
simpler if debugfs is used instead of /dev, so it makes sense to make the
conversion now for that reason. This patch removes the char interface and
replaces it with a debugfs interface. Raw samples will be acquired from
/sys/kernel/debug/gb_loopback/raw_latency_endo0❌y:z:w where
x = <module-id>
y = <interface-id>
z = <bundle-id>
w = <cport-number>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Bryan O'Donoghue
Greg Kroah-Hartman
parent
2f8423046f
commit
aa27bf8269
@ -17,6 +17,7 @@
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#include <linux/cdev.h>
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#include <linux/fs.h>
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#include <linux/kfifo.h>
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#include <linux/debugfs.h>
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#include <asm/div64.h>
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@ -31,16 +32,21 @@ struct gb_loopback_stats {
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u32 count;
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};
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struct gb_loopback_device {
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struct dentry *root;
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u32 count;
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};
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static struct gb_loopback_device gb_dev;
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struct gb_loopback {
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struct gb_connection *connection;
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struct dentry *file;
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struct kfifo kfifo;
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struct mutex mutex;
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struct task_struct *task;
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wait_queue_head_t wq;
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dev_t dev;
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struct cdev cdev;
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struct device *device;
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int type;
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u32 size;
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@ -60,16 +66,9 @@ struct gb_loopback {
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#define GB_LOOPBACK_FIFO_DEFAULT 8192
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static struct class *loopback_class;
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static int loopback_major;
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static const struct file_operations loopback_fops;
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static DEFINE_IDA(minors);
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static unsigned kfifo_depth = GB_LOOPBACK_FIFO_DEFAULT;
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module_param(kfifo_depth, uint, 0444);
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/* Number of minor devices this driver supports */
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#define NUM_MINORS 256
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/* Maximum size of any one send data buffer we support */
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#define MAX_PACKET_SIZE (PAGE_SIZE * 2)
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@ -515,35 +514,72 @@ static int gb_loopback_fn(void *data)
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return 0;
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}
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static int gb_loopback_dbgfs_latency_show(struct seq_file *s, void *unused)
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{
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struct gb_loopback *gb = s->private;
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u32 latency;
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int retval;
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if (kfifo_len(&gb->kfifo) == 0) {
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retval = -EAGAIN;
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goto done;
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}
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mutex_lock(&gb->mutex);
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retval = kfifo_out(&gb->kfifo, &latency, sizeof(latency));
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if (retval > 0) {
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seq_printf(s, "%u", latency);
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retval = 0;
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}
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mutex_unlock(&gb->mutex);
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done:
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return retval;
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}
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static int gb_loopback_latency_open(struct inode *inode, struct file *file)
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{
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return single_open(file, gb_loopback_dbgfs_latency_show,
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inode->i_private);
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}
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static const struct file_operations gb_loopback_debugfs_latency_ops = {
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.open = gb_loopback_latency_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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#define DEBUGFS_NAMELEN 24
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static int gb_loopback_connection_init(struct gb_connection *connection)
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{
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struct gb_loopback *gb;
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int retval;
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int minor;
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char name[DEBUGFS_NAMELEN];
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gb = kzalloc(sizeof(*gb), GFP_KERNEL);
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if (!gb)
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return -ENOMEM;
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gb_loopback_reset_stats(gb);
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snprintf(name, sizeof(name), "raw_latency_endo0:%d:%d:%d:%d",
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connection->bundle->intf->module->module_id,
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connection->bundle->intf->interface_id,
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connection->bundle->id,
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connection->intf_cport_id);
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gb->file = debugfs_create_file(name, S_IFREG | S_IRUGO, gb_dev.root, gb,
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&gb_loopback_debugfs_latency_ops);
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gb->connection = connection;
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connection->private = gb;
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retval = sysfs_create_groups(&connection->dev.kobj, loopback_groups);
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if (retval)
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goto out_free;
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/* Get a minor number */
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minor = ida_simple_get(&minors, 0, 0, GFP_KERNEL);
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if (minor < 0) {
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retval = minor;
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goto out_sysfs;
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}
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goto out_debugfs;
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/* Calculate maximum payload */
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gb->size_max = gb_operation_get_payload_size_max(connection);
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if (gb->size_max <= sizeof(struct gb_loopback_transfer_request)) {
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retval = -EINVAL;
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goto out_minor;
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goto out_sysfs;
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}
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gb->size_max -= sizeof(struct gb_loopback_transfer_request);
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@ -551,21 +587,7 @@ static int gb_loopback_connection_init(struct gb_connection *connection)
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if (kfifo_alloc(&gb->kfifo, kfifo_depth * sizeof(u32),
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GFP_KERNEL)) {
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retval = -ENOMEM;
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goto out_minor;
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}
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/* Create device entry */
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gb->dev = MKDEV(loopback_major, minor);
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cdev_init(&gb->cdev, &loopback_fops);
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retval = cdev_add(&gb->cdev, gb->dev, 1);
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if (retval)
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goto out_kfifo;
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gb->device = device_create(loopback_class, &connection->dev, gb->dev,
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gb, "gb!loopback%d", minor);
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if (IS_ERR(gb->device)) {
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retval = PTR_ERR(gb->device);
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goto out_cdev;
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goto out_sysfs;
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}
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/* Fork worker thread */
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@ -574,22 +596,18 @@ static int gb_loopback_connection_init(struct gb_connection *connection)
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gb->task = kthread_run(gb_loopback_fn, gb, "gb_loopback");
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if (IS_ERR(gb->task)) {
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retval = PTR_ERR(gb->task);
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goto out_device;
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goto out_kfifo;
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}
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gb_dev.count++;
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return 0;
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out_device:
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device_del(gb->device);
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out_cdev:
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cdev_del(&gb->cdev);
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out_kfifo:
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kfifo_free(&gb->kfifo);
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out_minor:
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ida_simple_remove(&minors, minor);
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out_sysfs:
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sysfs_remove_groups(&connection->dev.kobj, loopback_groups);
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out_free:
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out_debugfs:
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debugfs_remove(gb->file);
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connection->private = NULL;
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kfree(gb);
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@ -600,15 +618,14 @@ static void gb_loopback_connection_exit(struct gb_connection *connection)
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{
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struct gb_loopback *gb = connection->private;
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gb_dev.count--;
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connection->private = NULL;
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if (!IS_ERR_OR_NULL(gb->task))
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kthread_stop(gb->task);
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device_del(gb->device);
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cdev_del(&gb->cdev);
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kfifo_free(&gb->kfifo);
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ida_simple_remove(&minors, MINOR(gb->dev));
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sysfs_remove_groups(&connection->dev.kobj, loopback_groups);
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debugfs_remove(gb->file);
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kfree(gb);
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}
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@ -622,79 +639,17 @@ static struct gb_protocol loopback_protocol = {
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.request_recv = gb_loopback_request_recv,
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};
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static int loopback_open(struct inode *inode, struct file *file)
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{
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struct cdev *cdev = inode->i_cdev;
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struct gb_loopback *gb = container_of(cdev, struct gb_loopback, cdev);
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file->private_data = gb;
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return 0;
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}
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static ssize_t loopback_read(struct file *file, char __user *buf, size_t count,
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loff_t *ppos)
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{
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struct gb_loopback *gb = file->private_data;
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size_t fifo_len;
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int retval;
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if (!count || count % sizeof(u32))
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return -EINVAL;
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mutex_lock(&gb->mutex);
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fifo_len = kfifo_len(&gb->kfifo);
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if (kfifo_to_user(&gb->kfifo, buf, min(fifo_len, count), &retval) != 0)
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retval = -EIO;
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mutex_unlock(&gb->mutex);
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return retval;
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}
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static const struct file_operations loopback_fops = {
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.owner = THIS_MODULE,
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.read = loopback_read,
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.open = loopback_open,
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.llseek = noop_llseek,
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};
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static int loopback_init(void)
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{
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dev_t dev;
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int retval;
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loopback_class = class_create(THIS_MODULE, "gb_loopback");
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if (IS_ERR(loopback_class)) {
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retval = PTR_ERR(loopback_class);
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goto error_class;
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}
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retval = alloc_chrdev_region(&dev, 0, NUM_MINORS, "gb_loopback");
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if (retval < 0)
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goto error_chrdev;
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loopback_major = MAJOR(dev);
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retval = gb_protocol_register(&loopback_protocol);
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if (retval)
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goto error_gb;
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return 0;
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error_gb:
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unregister_chrdev_region(dev, NUM_MINORS);
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error_chrdev:
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class_destroy(loopback_class);
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error_class:
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return retval;
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gb_dev.root = debugfs_create_dir("gb_loopback", NULL);
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return gb_protocol_register(&loopback_protocol);
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}
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module_init(loopback_init);
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static void __exit loopback_exit(void)
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{
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debugfs_remove_recursive(gb_dev.root);
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gb_protocol_deregister(&loopback_protocol);
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unregister_chrdev_region(MKDEV(loopback_major, 0), NUM_MINORS);
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class_destroy(loopback_class);
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ida_destroy(&minors);
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}
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module_exit(loopback_exit);
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