From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753780AbeDSOtr (ORCPT ); Thu, 19 Apr 2018 10:49:47 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:47382 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753725AbeDSOtp (ORCPT ); Thu, 19 Apr 2018 10:49:45 -0400 From: Pierre Morel To: pasic@linux.vnet.ibm.com, bjsdjshi@linux.vnet.ibm.com Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, cohuck@redhat.com Subject: [PATCH 10/10] vfio: ccw: Let user wait when busy on IO Date: Thu, 19 Apr 2018 16:48:13 +0200 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1524149293-12658-1-git-send-email-pmorel@linux.vnet.ibm.com> References: <1524149293-12658-1-git-send-email-pmorel@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18041914-0020-0000-0000-00000413BD3A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18041914-0021-0000-0000-000042A80A4B Message-Id: <1524149293-12658-11-git-send-email-pmorel@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-19_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804190131 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the current implementation, we do not want to start a new SSCH command before the last one ends. Signed-off-by: Pierre Morel --- drivers/s390/cio/vfio_ccw_fsm.c | 3 +++ drivers/s390/cio/vfio_ccw_ops.c | 21 ++++++++++++++++++++- drivers/s390/cio/vfio_ccw_private.h | 4 +++- 3 files changed, 26 insertions(+), 2 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c index b77b8ad..4140292 100644 --- a/drivers/s390/cio/vfio_ccw_fsm.c +++ b/drivers/s390/cio/vfio_ccw_fsm.c @@ -195,6 +195,9 @@ static int fsm_irq(struct vfio_ccw_private *private) if (private->io_trigger) eventfd_signal(private->io_trigger, 1); + if (private->io_completion) + complete(private->io_completion); + return VFIO_CCW_STATE_IDLE; } diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c index f0f4071..346532d 100644 --- a/drivers/s390/cio/vfio_ccw_ops.c +++ b/drivers/s390/cio/vfio_ccw_ops.c @@ -171,6 +171,8 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev, struct vfio_ccw_private *private; struct ccw_io_region *region; union scsw *scsw; + int max_retries = 5; + DECLARE_COMPLETION_ONSTACK(completion); if (*ppos + count > sizeof(*region)) return -EINVAL; @@ -185,7 +187,24 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev, if ((scsw->cmd.fctl & SCSW_FCTL_START_FUNC) != SCSW_FCTL_START_FUNC) return -EINVAL; - vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_SSCH_REQ); + do { + switch (private->state) { + case VFIO_CCW_STATE_BUSY: + private->io_completion = &completion; + wait_for_completion(&completion); + break; + case VFIO_CCW_STATE_IDLE: + if (!vfio_ccw_fsm_event(private, + VFIO_CCW_EVENT_SSCH_REQ)) + return count; + break; + default: + return -EBUSY; + } + } while (max_retries--); + + if (max_retries <= 0) + return -EBUSY; if (region->ret_code != 0) return region->ret_code; diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h index dbef727..7cca078 100644 --- a/drivers/s390/cio/vfio_ccw_private.h +++ b/drivers/s390/cio/vfio_ccw_private.h @@ -39,6 +39,7 @@ struct vfio_ccw_private { struct subchannel *sch; int state; struct completion *completion; + struct completion *io_completion; atomic_t avail; struct mdev_device *mdev; struct notifier_block nb; @@ -93,12 +94,13 @@ enum vfio_ccw_event { typedef int (fsm_func_t)(struct vfio_ccw_private *); extern fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS]; -static inline void vfio_ccw_fsm_event(struct vfio_ccw_private *private, +static inline int vfio_ccw_fsm_event(struct vfio_ccw_private *private, int event) { mutex_lock(&private->state_mutex); private->state = vfio_ccw_jumptable[private->state][event](private); mutex_unlock(&private->state_mutex); + return private->io_region.ret_code; } extern struct workqueue_struct *vfio_ccw_work_q; -- 2.7.4