From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: [PATCH v3 6/8] vfio: ccw: Make FSM functions atomic Date: Tue, 12 Jun 2018 09:56:48 +0200 Message-ID: <1528790210-19535-7-git-send-email-pmorel@linux.ibm.com> References: <1528790210-19535-1-git-send-email-pmorel@linux.ibm.com> Return-path: In-Reply-To: <1528790210-19535-1-git-send-email-pmorel@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: 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 List-ID: We use mutex around the FSM function call to make the FSM event handling and state change atomic. Signed-off-by: Pierre Morel --- drivers/s390/cio/vfio_ccw_drv.c | 1 + drivers/s390/cio/vfio_ccw_private.h | 3 +++ 2 files changed, 4 insertions(+) diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c index e5a516a..98951d5 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -116,6 +116,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch) return -ENOMEM; private->sch = sch; dev_set_drvdata(&sch->dev, private); + mutex_init(&private->state_mutex); spin_lock_irq(sch->lock); private->state = VFIO_CCW_STATE_NOT_OPER; diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h index 521ba0b..e3dc12c 100644 --- a/drivers/s390/cio/vfio_ccw_private.h +++ b/drivers/s390/cio/vfio_ccw_private.h @@ -51,6 +51,7 @@ struct vfio_ccw_private { struct eventfd_ctx *io_trigger; struct work_struct io_work; struct work_struct event_work; + struct mutex state_mutex; } __aligned(8); extern int vfio_ccw_mdev_reg(struct subchannel *sch); @@ -92,7 +93,9 @@ 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, int event) { + mutex_lock(&private->state_mutex); private->state = vfio_ccw_jumptable[private->state][event](private); + mutex_unlock(&private->state_mutex); } extern struct workqueue_struct *vfio_ccw_work_q; -- 2.7.4