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Date: Mon, 28 Jan 2019 18:31:24 +0100
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Subject: Re: [Qemu-devel] [PATCH v2 2/5] vfio-ccw: concurrent I/O handling
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To: Eric Farman <farman@linux.ibm.com>
Cc: Halil Pasic <pasic@linux.ibm.com>, Farhan Ali <alifm@linux.ibm.com>, Pierre Morel <pmorel@linux.ibm.com>, linux-s390@vger.kernel.org, kvm@vger.kernel.org, qemu-devel@nongnu.org, qemu-s390x@nongnu.org, Alex Williamson <alex.williamson@redhat.com>

On Fri, 25 Jan 2019 15:22:56 -0500
Eric Farman <farman@linux.ibm.com> wrote:

> If we come into mdev_write with state=BUSY and we get the lock, 
> copy_from_user, and do our jump table we go to fsm_io_busy to set 
> ret_code and return -EAGAIN.  Why then don't we set the jump table for 
> state=NOT_OPER||STANDBY to do something that will return -EACCES instead 
> of how we currently do a direct return of -EACCES before all the 
> lock/copy stuff (and the jump table that would take us to fsm_io_error 
> and an error message before returning -EIO)?

If you phrase it like that, I'm wondering why we're not already doing
it that way :) We just need to make sure to revert to the previous
state on error instead of IDLE.