From: Eric Farman farman@linux.ibm.com
stable inclusion from stable-v5.10.137 commit b16d653bc7bbd3dbbdaeda4e032e01ed9d8b252c category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
[ Upstream commit cffcc109fd682075dee79bade3d60a07152a8fd1 ]
The routine vfio_ccw_sch_event() is tasked with handling subchannel events, specifically machine checks, on behalf of vfio-ccw. It correctly calls cio_update_schib(), and if that fails (meaning the subchannel is gone) it makes an FSM event call to mark the subchannel Not Operational.
If that worked, however, then it decides that if the FSM state was already Not Operational (implying the subchannel just came back), then it should simply change the FSM to partially- or fully-open.
Remove this trickery, since a subchannel returning will require more probing than simply "oh all is well again" to ensure it works correctly.
Fixes: bbe37e4cb8970 ("vfio: ccw: introduce a finite state machine") Signed-off-by: Eric Farman farman@linux.ibm.com Reviewed-by: Matthew Rosato mjrosato@linux.ibm.com Link: https://lore.kernel.org/r/20220707135737.720765-4-farman@linux.ibm.com Signed-off-by: Alex Williamson alex.williamson@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Wei Li liwei391@huawei.com --- drivers/s390/cio/vfio_ccw_drv.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-)
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c index 9b61e9b131ad..e3c1060b6056 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -288,19 +288,11 @@ static int vfio_ccw_sch_event(struct subchannel *sch, int process) if (work_pending(&sch->todo_work)) goto out_unlock;
- if (cio_update_schib(sch)) { - vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER); - rc = 0; - goto out_unlock; - } - - private = dev_get_drvdata(&sch->dev); - if (private->state == VFIO_CCW_STATE_NOT_OPER) { - private->state = private->mdev ? VFIO_CCW_STATE_IDLE : - VFIO_CCW_STATE_STANDBY; - } rc = 0;
+ if (cio_update_schib(sch)) + vfio_ccw_fsm_event(private, VFIO_CCW_EVENT_NOT_OPER); + out_unlock: spin_unlock_irqrestore(sch->lock, flags);