From 66d4e795422d40ae66f4485539281da64fc80c5e Mon Sep 17 00:00:00 2001 From: Tasos Sahanidis Date: Fri, 1 Apr 2022 00:47:00 +0300 Subject: [PATCH] usb: core: Don't hold the device lock while sleeping in do_proc_control() commit 0543e4e8852ef5ff1809ae62f1ea963e2ab23b66 upstream. Since commit ae8709b296d8 ("USB: core: Make do_proc_control() and do_proc_bulk() killable") if a device has the USB_QUIRK_DELAY_CTRL_MSG quirk set, it will temporarily block all other URBs (e.g. interrupts) while sleeping due to a control. This results in noticeable delays when, for example, a userspace usbfs application is sending URB interrupts at a high rate to a keyboard and simultaneously updates the lock indicators using controls. Interrupts with direction set to IN are also affected by this, meaning that delivery of HID reports (containing scancodes) to the usbfs application is delayed as well. This patch fixes the regression by calling msleep() while the device mutex is unlocked, as was the case originally with usb_control_msg(). Fixes: ae8709b296d8 ("USB: core: Make do_proc_control() and do_proc_bulk() killable") Cc: stable Acked-by: Alan Stern Signed-off-by: Tasos Sahanidis Link: https://lore.kernel.org/r/3e299e2a-13b9-ddff-7fee-6845e868bc06@tasossah.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/devio.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index fa66e6e587928..656ba91c32831 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1197,12 +1197,16 @@ static int do_proc_control(struct usb_dev_state *ps, usb_unlock_device(dev); i = usbfs_start_wait_urb(urb, tmo, &actlen); + + /* Linger a bit, prior to the next control message. */ + if (dev->quirks & USB_QUIRK_DELAY_CTRL_MSG) + msleep(200); usb_lock_device(dev); snoop_urb(dev, NULL, pipe, actlen, i, COMPLETE, tbuf, actlen); if (!i && actlen) { if (copy_to_user(ctrl->data, tbuf, actlen)) { ret = -EFAULT; - goto recv_fault; + goto done; } } } else { @@ -1219,6 +1223,10 @@ static int do_proc_control(struct usb_dev_state *ps, usb_unlock_device(dev); i = usbfs_start_wait_urb(urb, tmo, &actlen); + + /* Linger a bit, prior to the next control message. */ + if (dev->quirks & USB_QUIRK_DELAY_CTRL_MSG) + msleep(200); usb_lock_device(dev); snoop_urb(dev, NULL, pipe, actlen, i, COMPLETE, NULL, 0); } @@ -1230,10 +1238,6 @@ static int do_proc_control(struct usb_dev_state *ps, } ret = (i < 0 ? i : actlen); - recv_fault: - /* Linger a bit, prior to the next control message. */ - if (dev->quirks & USB_QUIRK_DELAY_CTRL_MSG) - msleep(200); done: kfree(dr); usb_free_urb(urb);