From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH 09/10] vfio: ccw: Suppressing the BOXED state Date: Thu, 3 May 2018 11:02:33 +0200 Message-ID: <0d95b955-1567-cead-35d2-9d784b74ffa0@linux.vnet.ibm.com> References: <1524149293-12658-1-git-send-email-pmorel@linux.vnet.ibm.com> <1524149293-12658-10-git-send-email-pmorel@linux.vnet.ibm.com> <20180425104429.582618f8.cohuck@redhat.com> <32efd6b2-78b0-ae44-3a64-a092f9d412fe@linux.vnet.ibm.com> <20180430174718.7b1e5651.cohuck@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20180430174718.7b1e5651.cohuck@redhat.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Cornelia Huck Cc: pasic@linux.vnet.ibm.com, bjsdjshi@linux.vnet.ibm.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org List-ID: On 30/04/2018 17:47, Cornelia Huck wrote: > On Wed, 25 Apr 2018 15:55:51 +0200 > Pierre Morel wrote: > >> On 25/04/2018 10:44, Cornelia Huck wrote: >>> On Thu, 19 Apr 2018 16:48:12 +0200 >>> Pierre Morel wrote: >>> >>>> VFIO_CCW_STATE_BOXED and VFIO_CCW_STATE_BUSY are the same >>>> states. >>>> Let's only keep one: VFIO_CCW_STATE_BUSY >>>> >>>> Signed-off-by: Pierre Morel >>>> --- >>>> drivers/s390/cio/vfio_ccw_fsm.c | 9 --------- >>>> drivers/s390/cio/vfio_ccw_private.h | 1 - >>>> 2 files changed, 10 deletions(-) >>> I think they were initially supposed to cover two different things: >>> - BUSY: we're currently dealing with an I/O request >>> - BOXED: the device currently won't talk to us or we won't talk to it >>> >>> It seems we never really did anything useful with BOXED; but should we? >>> >> I do not know what. > The BUSY state is something we know that we'll get out of soon-ish > (when the I/O request has finished). We could conceivably use a timeout > and drop to the BOXED state if we don't get an answer. Absolutely, timeout on requests is something I wanted to do in a second series. > > I think this plays also into the reserve/release and path handling > questions. One of the more common reasons for devices to become boxed > I've seen is another system doing a reserve on a dasd. > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany