Hi,
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()
Regards
Oliver
Signed-off-by: Oliver Neukum <[EMAIL PROTECTED]>
----
--- linux-2.6.22-rc2/drivers/usb/usb-skeleton.c 2007-05-22 14:50:34.000000000
+0200
+++ linux-2.6.22-rc2-autosuspend/drivers/usb/usb-skeleton.c 2007-05-25
12:47:51.000000000 +0200
@@ -54,16 +54,20 @@ 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)
{
@@ -138,6 +142,30 @@ static int skel_release(struct inode *in
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;
@@ -179,12 +207,16 @@ static void skel_write_bulk_callback(str
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 */
@@ -213,6 +245,17 @@ static ssize_t skel_write(struct file *f
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) {
@@ -244,13 +287,14 @@ static ssize_t skel_write(struct file *f
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 */
@@ -259,6 +303,8 @@ static ssize_t skel_write(struct file *f
return writesize;
+error_unanchor:
+ usb_unanchor_urb(urb);
error:
if (urb) {
usb_buffer_free(dev->udev, writesize, buf, urb->transfer_dma);
@@ -276,6 +322,7 @@ static const struct file_operations skel
.write = skel_write,
.open = skel_open,
.release = skel_release,
+ .flush = skel_flush,
};
/*
@@ -306,6 +353,8 @@ static int skel_probe(struct usb_interfa
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;
@@ -391,6 +440,15 @@ static void skel_disconnect(struct usb_i
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,
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