diff options
Diffstat (limited to 'drivers/usb/misc/ldusb.c')
| -rw-r--r-- | drivers/usb/misc/ldusb.c | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/drivers/usb/misc/ldusb.c b/drivers/usb/misc/ldusb.c index 11555bde655..7bad4940476 100644 --- a/drivers/usb/misc/ldusb.c +++ b/drivers/usb/misc/ldusb.c @@ -165,6 +165,8 @@ struct ld_usb { size_t interrupt_in_endpoint_size; int interrupt_in_running; int interrupt_in_done; + int buffer_overflow; + spinlock_t rbsl; char* interrupt_out_buffer; struct usb_endpoint_descriptor* interrupt_out_endpoint; @@ -230,10 +232,12 @@ static void ld_usb_interrupt_in_callback(struct urb *urb) } else { dbg_info(&dev->intf->dev, "%s: nonzero status received: %d\n", __FUNCTION__, urb->status); + spin_lock(&dev->rbsl); goto resubmit; /* maybe we can recover */ } } + spin_lock(&dev->rbsl); if (urb->actual_length > 0) { next_ring_head = (dev->ring_head+1) % ring_buffer_size; if (next_ring_head != dev->ring_tail) { @@ -244,21 +248,25 @@ static void ld_usb_interrupt_in_callback(struct urb *urb) dev->ring_head = next_ring_head; dbg_info(&dev->intf->dev, "%s: received %d bytes\n", __FUNCTION__, urb->actual_length); - } else + } else { dev_warn(&dev->intf->dev, "Ring buffer overflow, %d bytes dropped\n", urb->actual_length); + dev->buffer_overflow = 1; + } } resubmit: /* resubmit if we're still running */ - if (dev->interrupt_in_running && dev->intf) { + if (dev->interrupt_in_running && !dev->buffer_overflow && dev->intf) { retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC); - if (retval) + if (retval) { dev_err(&dev->intf->dev, "usb_submit_urb failed (%d)\n", retval); + dev->buffer_overflow = 1; + } } - + spin_unlock(&dev->rbsl); exit: dev->interrupt_in_done = 1; wake_up_interruptible(&dev->read_wait); @@ -330,6 +338,7 @@ static int ld_usb_open(struct inode *inode, struct file *file) /* initialize in direction */ dev->ring_head = 0; dev->ring_tail = 0; + dev->buffer_overflow = 0; usb_fill_int_urb(dev->interrupt_in_urb, interface_to_usbdev(interface), usb_rcvintpipe(interface_to_usbdev(interface), @@ -439,6 +448,7 @@ static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count, size_t *actual_buffer; size_t bytes_to_read; int retval = 0; + int rv; dev = file->private_data; @@ -460,7 +470,10 @@ static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count, } /* wait for data */ + spin_lock_irq(&dev->rbsl); if (dev->ring_head == dev->ring_tail) { + dev->interrupt_in_done = 0; + spin_unlock_irq(&dev->rbsl); if (file->f_flags & O_NONBLOCK) { retval = -EAGAIN; goto unlock_exit; @@ -468,6 +481,8 @@ static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count, retval = wait_event_interruptible(dev->read_wait, dev->interrupt_in_done); if (retval < 0) goto unlock_exit; + } else { + spin_unlock_irq(&dev->rbsl); } /* actual_buffer contains actual_length + interrupt_in_buffer */ @@ -486,6 +501,17 @@ static ssize_t ld_usb_read(struct file *file, char __user *buffer, size_t count, retval = bytes_to_read; + spin_lock_irq(&dev->rbsl); + if (dev->buffer_overflow) { + dev->buffer_overflow = 0; + spin_unlock_irq(&dev->rbsl); + rv = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL); + if (rv < 0) + dev->buffer_overflow = 1; + } else { + spin_unlock_irq(&dev->rbsl); + } + unlock_exit: /* unlock the device */ up(&dev->sem); @@ -635,6 +661,7 @@ static int ld_usb_probe(struct usb_interface *intf, const struct usb_device_id * goto exit; } init_MUTEX(&dev->sem); + spin_lock_init(&dev->rbsl); dev->intf = intf; init_waitqueue_head(&dev->read_wait); init_waitqueue_head(&dev->write_wait); |