linux-kernel - [PATCH AUTOSEL 5.10 11/39] vfio-ccw: Reset FSM state to IDLE inside FSM

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Date:   Thu,  3 Jun 2021 13:08:01 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Eric Farman <farman@...ux.ibm.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Matthew Rosato <mjrosato@...ux.ibm.com>,
        Sasha Levin <sashal@...nel.org>, linux-s390@...r.kernel.org,
        kvm@...r.kernel.org
Subject: [PATCH AUTOSEL 5.10 11/39] vfio-ccw: Reset FSM state to IDLE inside FSM

From: Eric Farman <farman@...ux.ibm.com>

[ Upstream commit 6c02ac4c9211edabe17bda437ac97e578756f31b ]

When an I/O request is made, the fsm_io_request() routine
moves the FSM state from IDLE to CP_PROCESSING, and then
fsm_io_helper() moves it to CP_PENDING if the START SUBCHANNEL
received a cc0. Yet, the error case to go from CP_PROCESSING
back to IDLE is done after the FSM call returns.

Let's move this up into the FSM proper, to provide some
better symmetry when unwinding in this case.

Signed-off-by: Eric Farman <farman@...ux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@...hat.com>
Acked-by: Matthew Rosato <mjrosato@...ux.ibm.com>
Message-Id: <20210511195631.3995081-3-farman@...ux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/s390/cio/vfio_ccw_fsm.c | 1 +
 drivers/s390/cio/vfio_ccw_ops.c | 2 --
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/s390/cio/vfio_ccw_fsm.c b/drivers/s390/cio/vfio_ccw_fsm.c
index 23e61aa638e4..e435a9cd92da 100644
--- a/drivers/s390/cio/vfio_ccw_fsm.c
+++ b/drivers/s390/cio/vfio_ccw_fsm.c
@@ -318,6 +318,7 @@ static void fsm_io_request(struct vfio_ccw_private *private,
 	}
 
 err_out:
+	private->state = VFIO_CCW_STATE_IDLE;
 	trace_vfio_ccw_fsm_io_request(scsw->cmd.fctl, schid,
 				      io_region->ret_code, errstr);
 }
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 1ad5f7018ec2..2280f51dd679 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -276,8 +276,6 @@ static ssize_t vfio_ccw_mdev_write_io_region(struct vfio_ccw_private *private,
 	}
 
 	vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_IO_REQ);
-	if (region->ret_code != 0)
-		private->state = VFIO_CCW_STATE_IDLE;
 	ret = (region->ret_code != 0) ? region->ret_code : count;
 
 out_unlock:
-- 
2.30.2