[v2] usb: core: hub: fix race condition about TRSMRCY of resume

Commit Message

Chunfeng Yun (云春峰) May 12, 2021, 2:07 a.m. UTC

This may happen if the port becomes resume status exactly
when usb_port_resume() gets port status, it still need provide
a TRSMCRY time before access the device.

CC: <[e-mail]>
Acked-by: Alan Stern <[e-mail]>
Reported-by: Tianping Fang <[e-mail]>
Signed-off-by: Chunfeng Yun <[e-mail]>
---
v2:
    cc stable suggested by Alan,
    and add acked-by Alan
---
 drivers/usb/core/hub.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Patch

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index b2bc4b7c4289..fc7d6cdacf16 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3642,9 +3642,6 @@  int usb_port_resume(struct usb_device *udev, pm_message_t msg)
 		 * sequence.
 		 */
 		status = hub_port_status(hub, port1, &portstatus, &portchange);
-
-		/* TRSMRCY = 10 msec */
-		msleep(10);
 	}
 
  SuspendCleared:
@@ -3659,6 +3656,9 @@  int usb_port_resume(struct usb_device *udev, pm_message_t msg)
 				usb_clear_port_feature(hub->hdev, port1,
 						USB_PORT_FEAT_C_SUSPEND);
 		}
+
+		/* TRSMRCY = 10 msec */
+		msleep(10);
 	}
 
 	if (udev->persist_enabled)