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Sat, 25 Jul 2026 16:39:58 +0000 (GMT) Received: from [9.61.125.168] (unknown [9.61.125.168]) by smtpav01.dal12v.mail.ibm.com (Postfix) with ESMTP; Sat, 25 Jul 2026 16:39:58 +0000 (GMT) Message-ID: <685bd45f-379e-4878-b76a-6c7a13f1c036@linux.ibm.com> Date: Sat, 25 Jul 2026 12:39:58 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 7/9] s390/vfio_ccw: move cp cleanup out of not operational To: Eric Farman , linux-s390@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Halil Pasic , Christian Borntraeger , stable@vger.kernel.org References: <20260725152705.3958100-1-farman@linux.ibm.com> <20260725152705.3958100-8-farman@linux.ibm.com> Content-Language: en-US From: Matthew Rosato In-Reply-To: <20260725152705.3958100-8-farman@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: HXxDusa_XfUgDxXaOPuj6aBCHRCZUP1P X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzI1MDE1NCBTYWx0ZWRfXxv/R22NOljok XxF6ZOgytnHCTZ3rfjXPQAWZZdR9gnTo+rHocEFmnA33IE5urVD2Q+1fAvmnjWD5sZmZaAPAyiQ 6OTd8oYirdeQhocnzcnGAthjq7ER0EUAJ0WfTDw4XBFqwbH2mMP8SnfJ21bsuvmYl0F7BN3F5/s uXlu8TNTTkeV5qa+Tvn1CrQlx/si0PQI2ssB4yEoZl7+INCCzxtqPmlBa6FeLGHfF6+Fz1nR9aL Z2rFOP0ctOBWnhkB1oJB8IbqCm3G5s+t27EBvRPmV+LIxt+zu71IiBn5fQd0H7aKsuai2hJ3XWm IfBgzeHqcChUkzuB+rFX1GYEZOz/8ILGKNRSxEhnTVGII6iXlrH4GxOTfd/5/DhR437cAG+ULiv Pn3qBuA+qXgzSCFSlfIZNyz2xYCEygk6Tu4NMQVFR4lasM4izGPS1KzNDHE0Cf7UGV5OYBXR2Ii Pp1J5hVnI0FGseO4seg== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzI1MDE1NCBTYWx0ZWRfX0QKs8gyWGabT 2p22a/usBW/kALpXmcDwJhNaD8kw0WlldT6kB65mQX5vF87+16pFVCNx14xIF+CmseBtpjWvnNN j8frwOzzq/NjlWEP6x420IYatjst1jk= X-Authority-Analysis: v=2.4 cv=AZeB2XXG c=1 sm=1 tr=0 ts=6a64e6e1 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=3NM-aQxfNb8fiyjzp1cA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: HXxDusa_XfUgDxXaOPuj6aBCHRCZUP1P X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-25_04,2026-07-24_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 priorityscore=1501 phishscore=0 adultscore=0 impostorscore=0 clxscore=1015 malwarescore=0 suspectscore=0 lowpriorityscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607250154 On 7/25/26 11:27 AM, Eric Farman wrote: > The fsm_notoper() routine is called when the device has been > lost, and is (by definition) no longer operational. Since this > can happen asynchronously from the normal behavior of the > driver, the cleanup may happen when holding other locks > in the calling sequence (notably, the cio subchannel lock). > > Push the cleanup of the private->cp resources to a workqueue, > where it can be done out from under that lock sequence and > (soon) under its own serialization mechanism. > > Fixes: 204b394a23ad ("vfio/ccw: Move FSM open/close to MDEV open/close") > Cc: stable@vger.kernel.org > Signed-off-by: Eric Farman Doesn't this need a cancel of the workqueue before the vfio_ccw_private gets freed, maybe in vfio_ccw_mdev_release_dev()? > --- > drivers/s390/cio/vfio_ccw_drv.c | 9 +++++++++ > drivers/s390/cio/vfio_ccw_fsm.c | 3 +-- > drivers/s390/cio/vfio_ccw_ops.c | 1 + > drivers/s390/cio/vfio_ccw_private.h | 3 +++ > 4 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c > index 1a095085bc72..c197ad5ab580 100644 > --- a/drivers/s390/cio/vfio_ccw_drv.c > +++ b/drivers/s390/cio/vfio_ccw_drv.c > @@ -125,6 +125,15 @@ void vfio_ccw_crw_todo(struct work_struct *work) > eventfd_signal(private->crw_trigger); > } > > +void vfio_ccw_notoper_todo(struct work_struct *work) > +{ > + struct vfio_ccw_private *private; > + > + private = container_of(work, struct vfio_ccw_private, notoper_work); > + > + cp_free(&private->cp); > +} > + > /* > * Css driver callbacks > */ > diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c > index 4d7988ea47ef..4d47a3c7b9a0 100644 > --- a/drivers/s390/cio/vfio_ccw_fsm.c > +++ b/drivers/s390/cio/vfio_ccw_fsm.c > @@ -170,8 +170,7 @@ static void fsm_notoper(struct vfio_ccw_private *private, > css_sched_sch_todo(sch, SCH_TODO_UNREG); > private->state = VFIO_CCW_STATE_NOT_OPER; > > - /* This is usually handled during CLOSE event */ > - cp_free(&private->cp); > + queue_work(vfio_ccw_work_q, &private->notoper_work); > } > > /* > diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c > index 032a1cdf4df7..6c74d596be9d 100644 > --- a/drivers/s390/cio/vfio_ccw_ops.c > +++ b/drivers/s390/cio/vfio_ccw_ops.c > @@ -54,6 +54,7 @@ static int vfio_ccw_mdev_init_dev(struct vfio_device *vdev) > INIT_LIST_HEAD(&private->crw); > INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo); > INIT_WORK(&private->crw_work, vfio_ccw_crw_todo); > + INIT_WORK(&private->notoper_work, vfio_ccw_notoper_todo); > > private->cp.guest_cp = kzalloc_objs(struct ccw1, CCWCHAIN_LEN_MAX); > if (!private->cp.guest_cp) > diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h > index 0501d4bbcdbd..e2256402b089 100644 > --- a/drivers/s390/cio/vfio_ccw_private.h > +++ b/drivers/s390/cio/vfio_ccw_private.h > @@ -102,6 +102,7 @@ struct vfio_ccw_parent { > * @req_trigger: eventfd ctx for signaling userspace to return device > * @io_work: work for deferral process of I/O handling > * @crw_work: work for deferral process of CRW handling > + * @notoper_work: work for deferred processing in not-operational state > */ > struct vfio_ccw_private { > struct vfio_device vdev; > @@ -125,11 +126,13 @@ struct vfio_ccw_private { > struct eventfd_ctx *req_trigger; > struct work_struct io_work; > struct work_struct crw_work; > + struct work_struct notoper_work; > } __aligned(8); > > int vfio_ccw_sch_quiesce(struct subchannel *sch); > void vfio_ccw_sch_io_todo(struct work_struct *work); > void vfio_ccw_crw_todo(struct work_struct *work); > +void vfio_ccw_notoper_todo(struct work_struct *work); > > extern struct mdev_driver vfio_ccw_mdev_driver; >