Date:   Thu, 11 Nov 2021 14:12:28 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Pavankumar Kondeti <quic_pkondeti@quicinc.com>
Cc:     linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        Felipe Balbi <balbi@kernel.org>, Jens Axboe <axboe@kernel.dk>,
        Jack Pham <jackp@codeaurora.org>,
        Peter Chen <peter.chen@nxp.com>,
        Wesley Cheng <wcheng@codeaurora.org>,
        Andrew Gabbasov <andrew_gabbasov@mentor.com>,
        kernel test robot <lkp@intel.com>
Subject: Re: [PATCH v2] usb: gadget: f_fs: Use stream_open() for endpoint
 files
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On Thu, Nov 11, 2021 at 05:45:56PM +0530, Pavankumar Kondeti wrote:
> Function fs endpoint files does not have the notion of file position.
> So switch to stream like functionality. This allows concurrent threads
> to be blocked in the ffs read/write operations which use ffs_mutex_lock().
> The ffs mutex lock deploys interruptible wait. Otherwise, threads are
> blocking for the mutex lock in __fdget_pos(). For whatever reason, ff the
> host does not send/receive data for longer time, hung task warnings
> are observed.

So the current code is broken?  What commit caused it to break?

Doesn't this change cause a change in behavior for existing userspace
tools, or will they still work as-is?

thanks,

greg k-h