Patch "usb: f_fs: Prevent gadget unbind if it is already unbound" has been added to the 4.14-stable tree

[<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 the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     usb-f_fs-prevent-gadget-unbind-if-it-is-already-unbound.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>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

From: Hemant Kumar <hemantk@codeaurora.org>

commit ce5bf9a50daf2d9078b505aca1cea22e88ecb94a upstream.

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>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/gadget/function/f_fs.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -3704,7 +3704,8 @@ static void ffs_closed(struct ffs_data *
 	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();


Patches currently in stable-queue which might be from hemantk@codeaurora.org are

queue-4.14/usb-f_fs-prevent-gadget-unbind-if-it-is-already-unbound.patch