USB: usbfs: allow URBs to be reaped after disconnection
The usbfs API has a peculiar hole: Users are not allowed to reap their URBs after the device has been disconnected. There doesn't seem to be any good reason for this; it is an ad-hoc inconsistency. The patch allows users to issue the USBDEVFS_REAPURB and USBDEVFS_REAPURBNDELAY ioctls (together with their 32-bit counterparts on 64-bit systems) even after the device is gone. If no URBs are pending for a disconnected device then the ioctls will return -ENODEV rather than -EAGAIN, because obviously no new URBs will ever be able to complete. The patch also adds a new capability flag for USBDEVFS_GET_CAPABILITIES to indicate that the reap-after-disconnect feature is supported. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Chris Dickens <christopher.a.dickens@gmail.com> Acked-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
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@ -1689,7 +1689,7 @@ static struct async *reap_as(struct usb_dev_state *ps)
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for (;;) {
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__set_current_state(TASK_INTERRUPTIBLE);
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as = async_getcompleted(ps);
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if (as)
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if (as || !connected(ps))
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break;
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if (signal_pending(current))
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break;
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@ -1712,7 +1712,7 @@ static int proc_reapurb(struct usb_dev_state *ps, void __user *arg)
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}
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if (signal_pending(current))
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return -EINTR;
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return -EIO;
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return -ENODEV;
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}
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static int proc_reapurbnonblock(struct usb_dev_state *ps, void __user *arg)
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@ -1721,10 +1721,11 @@ static int proc_reapurbnonblock(struct usb_dev_state *ps, void __user *arg)
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struct async *as;
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as = async_getcompleted(ps);
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retval = -EAGAIN;
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if (as) {
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retval = processcompl(as, (void __user * __user *)arg);
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free_async(as);
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} else {
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retval = (connected(ps) ? -EAGAIN : -ENODEV);
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}
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return retval;
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}
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@ -1854,7 +1855,7 @@ static int proc_reapurb_compat(struct usb_dev_state *ps, void __user *arg)
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}
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if (signal_pending(current))
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return -EINTR;
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return -EIO;
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return -ENODEV;
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}
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static int proc_reapurbnonblock_compat(struct usb_dev_state *ps, void __user *arg)
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@ -1862,11 +1863,12 @@ static int proc_reapurbnonblock_compat(struct usb_dev_state *ps, void __user *ar
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int retval;
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struct async *as;
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retval = -EAGAIN;
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as = async_getcompleted(ps);
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if (as) {
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retval = processcompl_compat(as, (void __user * __user *)arg);
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free_async(as);
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} else {
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retval = (connected(ps) ? -EAGAIN : -ENODEV);
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}
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return retval;
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}
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@ -2038,7 +2040,8 @@ static int proc_get_capabilities(struct usb_dev_state *ps, void __user *arg)
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{
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__u32 caps;
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caps = USBDEVFS_CAP_ZERO_PACKET | USBDEVFS_CAP_NO_PACKET_SIZE_LIM;
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caps = USBDEVFS_CAP_ZERO_PACKET | USBDEVFS_CAP_NO_PACKET_SIZE_LIM |
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USBDEVFS_CAP_REAP_AFTER_DISCONNECT;
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if (!ps->dev->bus->no_stop_on_short)
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caps |= USBDEVFS_CAP_BULK_CONTINUATION;
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if (ps->dev->bus->sg_tablesize)
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@ -2138,6 +2141,32 @@ static long usbdev_do_ioctl(struct file *file, unsigned int cmd,
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return -EPERM;
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usb_lock_device(dev);
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/* Reap operations are allowed even after disconnection */
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switch (cmd) {
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case USBDEVFS_REAPURB:
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snoop(&dev->dev, "%s: REAPURB\n", __func__);
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ret = proc_reapurb(ps, p);
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goto done;
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case USBDEVFS_REAPURBNDELAY:
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snoop(&dev->dev, "%s: REAPURBNDELAY\n", __func__);
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ret = proc_reapurbnonblock(ps, p);
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goto done;
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#ifdef CONFIG_COMPAT
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case USBDEVFS_REAPURB32:
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snoop(&dev->dev, "%s: REAPURB32\n", __func__);
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ret = proc_reapurb_compat(ps, p);
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goto done;
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case USBDEVFS_REAPURBNDELAY32:
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snoop(&dev->dev, "%s: REAPURBNDELAY32\n", __func__);
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ret = proc_reapurbnonblock_compat(ps, p);
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goto done;
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#endif
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}
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if (!connected(ps)) {
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usb_unlock_device(dev);
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return -ENODEV;
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@ -2231,16 +2260,6 @@ static long usbdev_do_ioctl(struct file *file, unsigned int cmd,
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inode->i_mtime = CURRENT_TIME;
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break;
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case USBDEVFS_REAPURB32:
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snoop(&dev->dev, "%s: REAPURB32\n", __func__);
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ret = proc_reapurb_compat(ps, p);
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break;
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case USBDEVFS_REAPURBNDELAY32:
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snoop(&dev->dev, "%s: REAPURBNDELAY32\n", __func__);
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ret = proc_reapurbnonblock_compat(ps, p);
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break;
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case USBDEVFS_IOCTL32:
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snoop(&dev->dev, "%s: IOCTL32\n", __func__);
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ret = proc_ioctl_compat(ps, ptr_to_compat(p));
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@ -2252,16 +2271,6 @@ static long usbdev_do_ioctl(struct file *file, unsigned int cmd,
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ret = proc_unlinkurb(ps, p);
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break;
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case USBDEVFS_REAPURB:
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snoop(&dev->dev, "%s: REAPURB\n", __func__);
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ret = proc_reapurb(ps, p);
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break;
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case USBDEVFS_REAPURBNDELAY:
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snoop(&dev->dev, "%s: REAPURBNDELAY\n", __func__);
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ret = proc_reapurbnonblock(ps, p);
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break;
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case USBDEVFS_DISCSIGNAL:
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snoop(&dev->dev, "%s: DISCSIGNAL\n", __func__);
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ret = proc_disconnectsignal(ps, p);
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@ -2304,6 +2313,8 @@ static long usbdev_do_ioctl(struct file *file, unsigned int cmd,
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ret = proc_free_streams(ps, p);
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break;
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}
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done:
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usb_unlock_device(dev);
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if (ret >= 0)
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inode->i_atime = CURRENT_TIME;
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@ -128,11 +128,12 @@ struct usbdevfs_hub_portinfo {
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char port [127]; /* e.g. port 3 connects to device 27 */
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};
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/* Device capability flags */
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/* System and bus capability flags */
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#define USBDEVFS_CAP_ZERO_PACKET 0x01
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#define USBDEVFS_CAP_BULK_CONTINUATION 0x02
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#define USBDEVFS_CAP_NO_PACKET_SIZE_LIM 0x04
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#define USBDEVFS_CAP_BULK_SCATTER_GATHER 0x08
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#define USBDEVFS_CAP_REAP_AFTER_DISCONNECT 0x10
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/* USBDEVFS_DISCONNECT_CLAIM flags & struct */
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