From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756132AbeDXIW0 (ORCPT ); Tue, 24 Apr 2018 04:22:26 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:35084 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755887AbeDXIWX (ORCPT ); Tue, 24 Apr 2018 04:22:23 -0400 Subject: Re: [PATCH 02/10] vfio: ccw: Transform FSM functions to return state To: Dong Jia Shi Cc: pasic@linux.vnet.ibm.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, cohuck@redhat.com References: <1524149293-12658-1-git-send-email-pmorel@linux.vnet.ibm.com> <1524149293-12658-3-git-send-email-pmorel@linux.vnet.ibm.com> <20180424072550.GW12194@bjsdjshi@linux.vnet.ibm.com> From: Pierre Morel Date: Tue, 24 Apr 2018 10:22:15 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180424072550.GW12194@bjsdjshi@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18042408-0012-0000-0000-000005CE1B20 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18042408-0013-0000-0000-0000194A896B Message-Id: <047dd088-6cba-c1fa-2295-05d31d7f4f2d@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-24_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 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-1804240083 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24/04/2018 09:25, Dong Jia Shi wrote: > * Pierre Morel [2018-04-19 16:48:05 +0200]: > >> We change the FSM functions to return the next state, >> and adapt the fsm_func_t function type. > I think I'd need to read the rest patches to understand why we need this > one, but no hurt to write some ideas that I noticed at my first glance. > See below please. > >> Signed-off-by: Pierre Morel >> --- >> drivers/s390/cio/vfio_ccw_fsm.c | 24 ++++++++++++++++-------- >> drivers/s390/cio/vfio_ccw_private.h | 5 +++-- >> 2 files changed, 19 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c >> index af88551..2f3108d 100644 >> --- a/drivers/s390/cio/vfio_ccw_fsm.c >> +++ b/drivers/s390/cio/vfio_ccw_fsm.c >> @@ -60,7 +60,7 @@ static int fsm_io_helper(struct vfio_ccw_private *private) >> } >> } >> >> -static void fsm_notoper(struct vfio_ccw_private *private, >> +static int fsm_notoper(struct vfio_ccw_private *private, >> enum vfio_ccw_event event) >> { >> struct subchannel *sch = private->sch; >> @@ -71,30 +71,34 @@ static void fsm_notoper(struct vfio_ccw_private *private, >> */ >> css_sched_sch_todo(sch, SCH_TODO_UNREG); >> private->state = VFIO_CCW_STATE_NOT_OPER; > Here.. > >> + return private->state; >> } >> >> /* >> * No operation action. >> */ >> -static void fsm_nop(struct vfio_ccw_private *private, >> +static int fsm_nop(struct vfio_ccw_private *private, >> enum vfio_ccw_event event) >> { >> + return private->state; >> } >> >> -static void fsm_io_error(struct vfio_ccw_private *private, >> +static int fsm_io_error(struct vfio_ccw_private *private, >> enum vfio_ccw_event event) >> { >> pr_err("vfio-ccw: FSM: I/O request from state:%d\n", private->state); >> private->io_region.ret_code = -EIO; >> + return private->state; >> } >> >> -static void fsm_io_busy(struct vfio_ccw_private *private, >> +static int fsm_io_busy(struct vfio_ccw_private *private, >> enum vfio_ccw_event event) >> { >> private->io_region.ret_code = -EBUSY; >> + return private->state; >> } >> >> -static void fsm_disabled_irq(struct vfio_ccw_private *private, >> +static int fsm_disabled_irq(struct vfio_ccw_private *private, >> enum vfio_ccw_event event) >> { >> struct subchannel *sch = private->sch; >> @@ -104,12 +108,13 @@ static void fsm_disabled_irq(struct vfio_ccw_private *private, >> * successful - should not happen, but we try to disable again. >> */ >> cio_disable_subchannel(sch); >> + return private->state; >> } >> >> /* >> * Deal with the ccw command request from the userspace. >> */ >> -static void fsm_io_request(struct vfio_ccw_private *private, >> +static int fsm_io_request(struct vfio_ccw_private *private, >> enum vfio_ccw_event event) >> { >> union orb *orb; >> @@ -141,7 +146,7 @@ static void fsm_io_request(struct vfio_ccw_private *private, >> cp_free(&private->cp); >> goto err_out; >> } >> - return; >> + return private->state; >> } else if (scsw->cmd.fctl & SCSW_FCTL_HALT_FUNC) { >> /* XXX: Handle halt. */ >> io_region->ret_code = -EOPNOTSUPP; >> @@ -154,12 +159,13 @@ static void fsm_io_request(struct vfio_ccw_private *private, >> >> err_out: >> private->state = VFIO_CCW_STATE_IDLE; > Here.. > >> + return private->state; >> } >> >> /* >> * Got an interrupt for a normal io (state busy). >> */ >> -static void fsm_irq(struct vfio_ccw_private *private, >> +static int fsm_irq(struct vfio_ccw_private *private, >> enum vfio_ccw_event event) >> { >> struct irb *irb = &private->irb; >> @@ -172,6 +178,8 @@ static void fsm_irq(struct vfio_ccw_private *private, >> >> if (private->io_trigger) >> eventfd_signal(private->io_trigger, 1); >> + >> + return private->state; >> } >> >> /* >> diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h >> index 78a66d9..f526b18 100644 >> --- a/drivers/s390/cio/vfio_ccw_private.h >> +++ b/drivers/s390/cio/vfio_ccw_private.h >> @@ -83,13 +83,14 @@ enum vfio_ccw_event { >> /* >> * Action called through jumptable. >> */ >> -typedef void (fsm_func_t)(struct vfio_ccw_private *, enum vfio_ccw_event); >> +typedef int (fsm_func_t)(struct vfio_ccw_private *, enum vfio_ccw_event); >> 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) >> { >> - vfio_ccw_jumptable[private->state][event](private, event); >> + private->state = vfio_ccw_jumptable[private->state][event](private, >> + event); > Since here it assigns new value to private->state, there is no need to > do that inside each fsm_func? Absolutely. I just kept the previous code, just adding the return private->state in the functions in this patch. merging the state and the return value is done in a later patch. If you prefer I can do it in this patch. > >> } >> >> extern struct workqueue_struct *vfio_ccw_work_q; >> -- >> 2.7.4 >> -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany