Re: [PATCH RESEND 2/2] Mass storage gadget: Handle eject request

From: Alan Stern
Date: Fri Apr 23 2010 - 10:23:41 EST


On Fri, 23 Apr 2010 fabien.chouteau@xxxxxxxxx wrote:

> From: Fabien Chouteau <fabien.chouteau@xxxxxxxxx>
>
> This patch adds handling of the "Start/Stop Unit" SCSI request to simulate media
> ejection. A sysfs entry to get the "eject" state of a LUN is also added.

Sorry I didn't notice this earlier...

> --- a/drivers/usb/gadget/f_mass_storage.c
> +++ b/drivers/usb/gadget/f_mass_storage.c
> @@ -163,6 +163,13 @@
> * ro setting are not allowed when the medium is loaded or if CD-ROM
> * emulation is being used.
> *
> + * When a LUN receive an "eject" SCSI request (Start/Stop Unit),
> + * if the LUN is removable, the backing file is released to simulate
> + * ejection.
> + * The "eject" state of a LUN is available in the "ejected" file of the
> + * LUN's sysfs directory (see above). The "eject" state is only updated
> + * by SCSI request, not by user ejection.

What's the reason for that? With a real removable device, like a CD
player, it doesn't make any difference whether the medium was ejected
because of a SCSI command or because I pressed the "eject" button.

I just don't see any point in keeping track of the two actions
separately, since they end up having the same final result.

Alan Stern

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