Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947000AbbGaUwA (ORCPT ); Fri, 31 Jul 2015 16:52:00 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:47747 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755645AbbGaUTY (ORCPT ); Fri, 31 Jul 2015 16:19:24 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , Chris Dickens , Hans de Goede Subject: [PATCH 3.14 109/125] USB: usbfs: allow URBs to be reaped after disconnection Date: Fri, 31 Jul 2015 12:41:49 -0700 Message-Id: <20150731194030.973838652@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150731194027.037807932@linuxfoundation.org> References: <20150731194027.037807932@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5889 Lines: 198 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit 3f2cee73b650921b2e214bf487b2061a1c266504 upstream. 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 Tested-by: Chris Dickens Acked-by: Hans de Goede Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/devio.c | 63 ++++++++++++++++++++++---------------- include/uapi/linux/usbdevice_fs.h | 3 + 2 files changed, 39 insertions(+), 27 deletions(-) --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1591,7 +1591,7 @@ static struct async *reap_as(struct dev_ for (;;) { __set_current_state(TASK_INTERRUPTIBLE); as = async_getcompleted(ps); - if (as) + if (as || !connected(ps)) break; if (signal_pending(current)) break; @@ -1614,7 +1614,7 @@ static int proc_reapurb(struct dev_state } if (signal_pending(current)) return -EINTR; - return -EIO; + return -ENODEV; } static int proc_reapurbnonblock(struct dev_state *ps, void __user *arg) @@ -1623,10 +1623,11 @@ static int proc_reapurbnonblock(struct d struct async *as; as = async_getcompleted(ps); - retval = -EAGAIN; if (as) { retval = processcompl(as, (void __user * __user *)arg); free_async(as); + } else { + retval = (connected(ps) ? -EAGAIN : -ENODEV); } return retval; } @@ -1756,7 +1757,7 @@ static int proc_reapurb_compat(struct de } if (signal_pending(current)) return -EINTR; - return -EIO; + return -ENODEV; } static int proc_reapurbnonblock_compat(struct dev_state *ps, void __user *arg) @@ -1764,11 +1765,12 @@ static int proc_reapurbnonblock_compat(s int retval; struct async *as; - retval = -EAGAIN; as = async_getcompleted(ps); if (as) { retval = processcompl_compat(as, (void __user * __user *)arg); free_async(as); + } else { + retval = (connected(ps) ? -EAGAIN : -ENODEV); } return retval; } @@ -1940,7 +1942,8 @@ static int proc_get_capabilities(struct { __u32 caps; - caps = USBDEVFS_CAP_ZERO_PACKET | USBDEVFS_CAP_NO_PACKET_SIZE_LIM; + caps = USBDEVFS_CAP_ZERO_PACKET | USBDEVFS_CAP_NO_PACKET_SIZE_LIM | + USBDEVFS_CAP_REAP_AFTER_DISCONNECT; if (!ps->dev->bus->no_stop_on_short) caps |= USBDEVFS_CAP_BULK_CONTINUATION; if (ps->dev->bus->sg_tablesize) @@ -2001,6 +2004,32 @@ static long usbdev_do_ioctl(struct file return -EPERM; usb_lock_device(dev); + + /* Reap operations are allowed even after disconnection */ + switch (cmd) { + case USBDEVFS_REAPURB: + snoop(&dev->dev, "%s: REAPURB\n", __func__); + ret = proc_reapurb(ps, p); + goto done; + + case USBDEVFS_REAPURBNDELAY: + snoop(&dev->dev, "%s: REAPURBNDELAY\n", __func__); + ret = proc_reapurbnonblock(ps, p); + goto done; + +#ifdef CONFIG_COMPAT + case USBDEVFS_REAPURB32: + snoop(&dev->dev, "%s: REAPURB32\n", __func__); + ret = proc_reapurb_compat(ps, p); + goto done; + + case USBDEVFS_REAPURBNDELAY32: + snoop(&dev->dev, "%s: REAPURBNDELAY32\n", __func__); + ret = proc_reapurbnonblock_compat(ps, p); + goto done; +#endif + } + if (!connected(ps)) { usb_unlock_device(dev); return -ENODEV; @@ -2094,16 +2123,6 @@ static long usbdev_do_ioctl(struct file inode->i_mtime = CURRENT_TIME; break; - case USBDEVFS_REAPURB32: - snoop(&dev->dev, "%s: REAPURB32\n", __func__); - ret = proc_reapurb_compat(ps, p); - break; - - case USBDEVFS_REAPURBNDELAY32: - snoop(&dev->dev, "%s: REAPURBNDELAY32\n", __func__); - ret = proc_reapurbnonblock_compat(ps, p); - break; - case USBDEVFS_IOCTL32: snoop(&dev->dev, "%s: IOCTL32\n", __func__); ret = proc_ioctl_compat(ps, ptr_to_compat(p)); @@ -2115,16 +2134,6 @@ static long usbdev_do_ioctl(struct file ret = proc_unlinkurb(ps, p); break; - case USBDEVFS_REAPURB: - snoop(&dev->dev, "%s: REAPURB\n", __func__); - ret = proc_reapurb(ps, p); - break; - - case USBDEVFS_REAPURBNDELAY: - snoop(&dev->dev, "%s: REAPURBNDELAY\n", __func__); - ret = proc_reapurbnonblock(ps, p); - break; - case USBDEVFS_DISCSIGNAL: snoop(&dev->dev, "%s: DISCSIGNAL\n", __func__); ret = proc_disconnectsignal(ps, p); @@ -2161,6 +2170,8 @@ static long usbdev_do_ioctl(struct file ret = proc_disconnect_claim(ps, p); break; } + + done: usb_unlock_device(dev); if (ret >= 0) inode->i_atime = CURRENT_TIME; --- a/include/uapi/linux/usbdevice_fs.h +++ b/include/uapi/linux/usbdevice_fs.h @@ -125,11 +125,12 @@ struct usbdevfs_hub_portinfo { char port [127]; /* e.g. port 3 connects to device 27 */ }; -/* Device capability flags */ +/* System and bus capability flags */ #define USBDEVFS_CAP_ZERO_PACKET 0x01 #define USBDEVFS_CAP_BULK_CONTINUATION 0x02 #define USBDEVFS_CAP_NO_PACKET_SIZE_LIM 0x04 #define USBDEVFS_CAP_BULK_SCATTER_GATHER 0x08 +#define USBDEVFS_CAP_REAP_AFTER_DISCONNECT 0x10 /* USBDEVFS_DISCONNECT_CLAIM flags & struct */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/