patch "usb: f_fs: Prevent gadget unbind if it is already unbound" added to usb-testing

[<gregkh@linuxfoundation.org>]

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

    usb: f_fs: Prevent gadget unbind if it is already unbound

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-testing 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 be merged to the usb-next branch sometime soon,
after it passes testing, and the merge window is open.

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


>From ce5bf9a50daf2d9078b505aca1cea22e88ecb94a Mon Sep 17 00:00:00 2001
From: Hemant Kumar <hemantk@codeaurora.org>
Date: Tue, 9 Jan 2018 12:30:53 +0530
Subject: usb: f_fs: Prevent gadget unbind if it is already unbound

Upon usb composition switch there is possibility of ep0 file
release happening after gadget driver bind. In case of composition
switch from adb to a non-adb composition gadget will never gets
bound again resulting into failure of usb device enumeration. Fix
this issue by checking FFS_FL_BOUND flag and avoid extra
gadget driver unbind if it is already done as part of composition
switch.

This fixes adb reconnection error reported on Android running
v4.4 and above kernel versions. Verified on Hikey running vanilla
v4.15-rc7 + few out of tree Mali patches.

Reviewed-at: https://android-review.googlesource.com/#/c/582632/

Cc: Felipe Balbi <balbi@kernel.org>
Cc: Greg KH <gregkh@linux-foundation.org>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Badhri <badhri@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Cc: stable@vger.kernel.org
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
[AmitP: Cherry-picked it from android-4.14 and updated the commit log]
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/gadget/function/f_fs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 038a27a13ebc..686af89323a5 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -3703,7 +3703,8 @@ static void ffs_closed(struct ffs_data *ffs)
 	ci = opts->func_inst.group.cg_item.ci_parent->ci_parent;
 	ffs_dev_unlock();
 
-	unregister_gadget_item(ci);
+	if (test_bit(FFS_FL_BOUND, &ffs->flags))
+		unregister_gadget_item(ci);
 	return;
 done:
 	ffs_dev_unlock();
-- 
2.15.1