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USB: usb-skeleton: usb anchor to implement flush

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This patch set introduces usb_anchor and uses it to implement all modern
APIs in the skeleton driver.

- proper error reporting in the skeleton driver
- implementation of flush()

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Oliver Neukum 2007-05-25 13:42:56 +02:00 • committed by Greg Kroah-Hartman
commit 403dfb58c3
1 changed files with 65 additions and 7 deletions
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72
drivers/usb/usb-skeleton.c
View file

@ -51,16 +51,20 @@ struct usb_skel {
struct usb_device *udev; /* the usb device for this device */
struct usb_interface *interface; /* the interface for this device */
struct semaphore limit_sem; /* limiting the number of writes in progress */
struct usb_anchor submitted; /* in case we need to retract our submissions */
unsigned char *bulk_in_buffer; /* the buffer to receive data */
size_t bulk_in_size; /* the size of the receive buffer */
__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
__u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
int errors; /* the last request tanked */
spinlock_t err_lock; /* lock for errors */
struct kref kref;
struct mutex io_mutex; /* synchronize I/O with disconnect */
};
#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
static struct usb_driver skel_driver;
static void skel_draw_down(struct usb_skel *dev);
static void skel_delete(struct kref *kref)
{
@ -130,6 +134,30 @@ static int skel_release(struct inode *inode, struct file *file)
return 0;
}
static int skel_flush(struct file *file, fl_owner_t id)
{
struct usb_skel *dev;
int res;
dev = (struct usb_skel *)file->private_data;
if (dev == NULL)
return -ENODEV;
/* wait for io to stop */
mutex_lock(&dev->io_mutex);
skel_draw_down(dev);
/* read out errors, leave subsequent opens a clean slate */
spin_lock_irq(&dev->err_lock);
res = dev->errors ? (dev->errors == -EPIPE ? -EPIPE : -EIO) : 0;
dev->errors = 0;
spin_unlock_irq(&dev->err_lock);
mutex_unlock(&dev->io_mutex);
return res;
}
static ssize_t skel_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
{
struct usb_skel *dev;
@ -171,12 +199,16 @@ static void skel_write_bulk_callback(struct urb *urb)
dev = (struct usb_skel *)urb->context;
/* sync/async unlink faults aren't errors */
if (urb->status &&
!(urb->status == -ENOENT ||
urb->status == -ECONNRESET ||
urb->status == -ESHUTDOWN)) {
err("%s - nonzero write bulk status received: %d",
__FUNCTION__, urb->status);
if (urb->status) {
if(!(urb->status == -ENOENT ||
urb->status == -ECONNRESET ||
urb->status == -ESHUTDOWN))
err("%s - nonzero write bulk status received: %d",
__FUNCTION__, urb->status);
spin_lock(&dev->err_lock);
dev->errors = urb->status;
spin_unlock(&dev->err_lock);
}
/* free up our allocated buffer */
@ -205,6 +237,17 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou
goto exit;
}
spin_lock_irq(&dev->err_lock);
if ((retval = dev->errors) < 0) {
/* any error is reported once */
dev->errors = 0;
/* to preserve notifications about reset */
retval = (retval == -EPIPE) ? retval : -EIO;
}
spin_unlock_irq(&dev->err_lock);
if (retval < 0)
goto error;
/* create a urb, and a buffer for it, and copy the data to the urb */
urb = usb_alloc_urb(0, GFP_KERNEL);
if (!urb) {
@ -236,13 +279,14 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou
usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
buf, writesize, skel_write_bulk_callback, dev);
urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
usb_anchor_urb(urb, &dev->submitted);
/* send the data out the bulk port */
retval = usb_submit_urb(urb, GFP_KERNEL);
mutex_unlock(&dev->io_mutex);
if (retval) {
err("%s - failed submitting write urb, error %d", __FUNCTION__, retval);
goto error;
goto error_unanchor;
}
/* release our reference to this urb, the USB core will eventually free it entirely */
@ -251,6 +295,8 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, size_t cou
return writesize;
error_unanchor:
usb_unanchor_urb(urb);
error:
if (urb) {
usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
@ -268,6 +314,7 @@ static const struct file_operations skel_fops = {
.write = skel_write,
.open = skel_open,
.release = skel_release,
.flush = skel_flush,
};
/*
@ -298,6 +345,8 @@ static int skel_probe(struct usb_interface *interface, const struct usb_device_i
kref_init(&dev->kref);
sema_init(&dev->limit_sem, WRITES_IN_FLIGHT);
mutex_init(&dev->io_mutex);
spin_lock_init(&dev->err_lock);
init_usb_anchor(&dev->submitted);
dev->udev = usb_get_dev(interface_to_usbdev(interface));
dev->interface = interface;
@ -377,6 +426,15 @@ static void skel_disconnect(struct usb_interface *interface)
info("USB Skeleton #%d now disconnected", minor);
}
static void skel_draw_down(struct usb_skel *dev)
{
int time;
time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
if (!time)
usb_kill_anchored_urbs(&dev->submitted);
}
static struct usb_driver skel_driver = {
.name = "skeleton",
.probe = skel_probe,