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2af7a834a4
Today, the stacked call to vfio_ccw_sch_io_todo() does three things: 1) Update a solicited IRB with CP information, and release the CP if the interrupt was the end of a START operation. 2) Copy the IRB data into the io_region, under the protection of the io_mutex 3) Reset the vfio-ccw FSM state to IDLE to acknowledge that vfio-ccw can accept more work. The trouble is that step 3 is (A) invoked for both solicited and unsolicited interrupts, and (B) sitting after the mutex for step 2. This second piece becomes a problem if it processes an interrupt for a CLEAR SUBCHANNEL while another thread initiates a START, thus allowing the CP and FSM states to get out of sync. That is: CPU 1 CPU 2 fsm_do_clear() fsm_irq() fsm_io_request() vfio_ccw_sch_io_todo() fsm_io_helper() Since the FSM state and CP should be kept in sync, let's make a note when the CP is released, and rely on that as an indication that the FSM should also be reset at the end of this routine and open up the device for more work. Signed-off-by: Eric Farman <farman@linux.ibm.com> Acked-by: Matthew Rosato <mjrosato@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <20210511195631.3995081-4-farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com> |
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.. | ||
airq.c | ||
blacklist.c | ||
blacklist.h | ||
ccwgroup.c | ||
ccwreq.c | ||
chp.c | ||
chp.h | ||
chsc.c | ||
chsc.h | ||
chsc_sch.c | ||
chsc_sch.h | ||
cio.c | ||
cio.h | ||
cio_debug.h | ||
cio_debugfs.c | ||
cio_inject.c | ||
cio_inject.h | ||
cmf.c | ||
crw.c | ||
css.c | ||
css.h | ||
device.c | ||
device.h | ||
device_fsm.c | ||
device_id.c | ||
device_ops.c | ||
device_pgid.c | ||
device_status.c | ||
eadm_sch.c | ||
eadm_sch.h | ||
fcx.c | ||
idset.c | ||
idset.h | ||
io_sch.h | ||
ioasm.c | ||
ioasm.h | ||
isc.c | ||
itcw.c | ||
Makefile | ||
orb.h | ||
qdio.h | ||
qdio_debug.c | ||
qdio_debug.h | ||
qdio_main.c | ||
qdio_setup.c | ||
qdio_thinint.c | ||
scm.c | ||
trace.c | ||
trace.h | ||
vfio_ccw_async.c | ||
vfio_ccw_chp.c | ||
vfio_ccw_cp.c | ||
vfio_ccw_cp.h | ||
vfio_ccw_drv.c | ||
vfio_ccw_fsm.c | ||
vfio_ccw_ops.c | ||
vfio_ccw_private.h | ||
vfio_ccw_trace.c | ||
vfio_ccw_trace.h |