patch "USB: hub: fix up early-exit pathway in hub_activate" added to usb-linus

patch "USB: hub: fix up early-exit pathway in hub_activate" added to usb-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    USB: hub: fix up early-exit pathway in hub_activate

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From ca5cbc8b02f9b21cc8cd1ab36668763ec34f9ee8 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@rowland.harvard.edu>
Date: Fri, 5 Aug 2016 11:49:45 -0400
Subject: USB: hub: fix up early-exit pathway in hub_activate

The early-exit pathway in hub_activate, added by commit e50293ef9775
("USB: fix invalid memory access in hub_activate()") needs
improvement.  It duplicates code that is already present at the end of
the subroutine, and it neglects to undo the effect of a
usb_autopm_get_interface_no_resume() call.

This patch fixes both problems by making the early-exit pathway jump
directly to the end of the subroutine.  It simplifies the code at the
end by merging two conditionals that actually test the same condition
although they appear different: If type < HUB_INIT3 then type must be
either HUB_INIT2 or HUB_INIT, and it can't be HUB_INIT because in that
case the subroutine would have exited earlier.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@vger.kernel.org> #4.4+
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/core/hub.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 3ccffac0f647..bb69d262b6f9 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1055,11 +1055,8 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
 		device_lock(hub->intfdev);
 
 		/* Was the hub disconnected while we were waiting? */
-		if (hub->disconnected) {
-			device_unlock(hub->intfdev);
-			kref_put(&hub->kref, hub_release);
-			return;
-		}
+		if (hub->disconnected)
+			goto disconnected;
 		if (type == HUB_INIT2)
 			goto init2;
 		goto init3;
@@ -1281,12 +1278,12 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
 	/* Scan all ports that need attention */
 	kick_hub_wq(hub);
 
-	/* Allow autosuspend if it was suppressed */
-	if (type <= HUB_INIT3)
+	if (type == HUB_INIT2 || type == HUB_INIT3) {
+		/* Allow autosuspend if it was suppressed */
+ disconnected:
 		usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
-
-	if (type == HUB_INIT2 || type == HUB_INIT3)
 		device_unlock(hub->intfdev);
+	}
 
 	kref_put(&hub->kref, hub_release);
 }
-- 
2.9.2