From: Alan Stern <stern@rowland.harvard.edu>
To: Florian Faber <faber@faberman.de>
Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org
Subject: Re: [PATCH] usb: gadget: f_mass_storage: Shut down mass storage device when USB connection is shut, down.
Date: Sat, 4 Sep 2021 12:09:51 -0400 [thread overview]
Message-ID: <20210904160951.GA493355@rowland.harvard.edu> (raw)
In-Reply-To: <5f9fbabd-2e2c-9389-446d-3bd1dd954a82@faberman.de>
On Sat, Sep 04, 2021 at 05:32:58PM +0200, Florian Faber wrote:
> f_mass_storage continues to send out packets after the connection to the USB
> host has been terminated, ignoring the error status.
The driver doesn't send packets after the connection has been terminated --
that would be impossible. It may _try_ to send packets, but it can't
actually send anything unless the hosts asks for the data. There's nothing
wrong with trying and failing.
> Signed-off-by: Florian Faber <faber@faberman.de>
>
> ---
> drivers/usb/gadget/function/f_mass_storage.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/usb/gadget/function/f_mass_storage.c
> b/drivers/usb/gadget/function/f_mass_storage.c
> index 6ad669dde41c..1e73ba629e43 100644
> --- a/drivers/usb/gadget/function/f_mass_storage.c
> +++ b/drivers/usb/gadget/function/f_mass_storage.c
> @@ -529,6 +529,10 @@ static int start_transfer(struct fsg_dev *fsg, struct
> usb_ep *ep,
> /* We can't do much more than wait for a reset */
> req->status = rc;
>
> + if (rc==-ESHUTDOWN) {
> + fsg->common->running = 0;
> + }
> +
This is wrong because it isn't what common->running means. common->running
means that the mass-storage configuration has been set by the host; it has
nothing to do with whether or not the USB cable is connected.
Also the new code doesn't conform to the kernel's programming style (missing
spaces around the "==" sign and braces not needed for a single-line
conditional statement). And if it were a serious change, it should be
merged with the conditional statement that follows, which also tests whether
rc is -ESHUTDOWN.
Alan Stern
next prev parent reply other threads:[~2021-09-04 16:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-04 15:32 [PATCH] usb: gadget: f_mass_storage: Shut down mass storage device when USB connection is shut, down Florian Faber
2021-09-04 16:09 ` Alan Stern [this message]
2021-09-04 16:17 ` Florian Faber
2021-09-04 16:25 ` Alan Stern
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