4.14-stable review patch. If anyone has any objections, please let me know.
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From: Cornelia Huck cohuck@redhat.com
commit 3368e547c52b96586f0edf9657ca12b94d8e61a7 upstream.
When we call ssch, an interrupt might already be pending once we return from the START SUBCHANNEL instruction. Therefore we need to make sure interrupts are disabled while holding the subchannel lock until after we're done with our processing.
Cc: stable@vger.kernel.org #v4.12+ Reviewed-by: Dong Jia Shi bjsdjshi@linux.ibm.com Acked-by: Halil Pasic pasic@linux.vnet.ibm.com Acked-by: Pierre Morel pmorel@linux.vnet.ibm.com Signed-off-by: Cornelia Huck cohuck@redhat.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/s390/cio/vfio_ccw_fsm.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
--- a/drivers/s390/cio/vfio_ccw_fsm.c +++ b/drivers/s390/cio/vfio_ccw_fsm.c @@ -20,12 +20,12 @@ static int fsm_io_helper(struct vfio_ccw int ccode; __u8 lpm; unsigned long flags; + int ret;
sch = private->sch;
spin_lock_irqsave(sch->lock, flags); private->state = VFIO_CCW_STATE_BUSY; - spin_unlock_irqrestore(sch->lock, flags);
orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm);
@@ -38,10 +38,12 @@ static int fsm_io_helper(struct vfio_ccw * Initialize device status information */ sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND; - return 0; + ret = 0; + break; case 1: /* Status pending */ case 2: /* Busy */ - return -EBUSY; + ret = -EBUSY; + break; case 3: /* Device/path not operational */ { lpm = orb->cmd.lpm; @@ -51,13 +53,16 @@ static int fsm_io_helper(struct vfio_ccw sch->lpm = 0;
if (cio_update_schib(sch)) - return -ENODEV; - - return sch->lpm ? -EACCES : -ENODEV; + ret = -ENODEV; + else + ret = sch->lpm ? -EACCES : -ENODEV; + break; } default: - return ccode; + ret = ccode; } + spin_unlock_irqrestore(sch->lock, flags); + return ret; }
static void fsm_notoper(struct vfio_ccw_private *private,