vfio/ccw: remove private->sch

These places all rely on the ability to jump from a private
struct back to the subchannel struct. Rather than keeping a
copy in our back pocket, let's use the relationship provided
by the vfio_device embedded within the private.
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20221104142007.1314999-3-farman@linux.ibm.comSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/s390/cio/vfio_ccw_chp.c

@@ -16,6 +16,7 @@ static ssize_t vfio_ccw_schib_region_read(struct vfio_ccw_private *private,
 					  char __user *buf, size_t count,
 					  loff_t *ppos)
 {
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
 	unsigned int i = VFIO_CCW_OFFSET_TO_INDEX(*ppos) - VFIO_CCW_NUM_REGIONS;
 	loff_t pos = *ppos & VFIO_CCW_OFFSET_MASK;
 	struct ccw_schib_region *region;
@@ -27,12 +28,12 @@ static ssize_t vfio_ccw_schib_region_read(struct vfio_ccw_private *private,
 	mutex_lock(&private->io_mutex);
 	region = private->region[i].data;
 
-	if (cio_update_schib(private->sch)) {
+	if (cio_update_schib(sch)) {
 		ret = -ENODEV;
 		goto out;
 	}
 
-	memcpy(region, &private->sch->schib, sizeof(*region));
+	memcpy(region, &sch->schib, sizeof(*region));
 
 	if (copy_to_user(buf, (void *)region + pos, count)) {
 		ret = -EFAULT;

drivers/s390/cio/vfio_ccw_drv.c

@@ -160,7 +160,6 @@ static struct vfio_ccw_private *vfio_ccw_alloc_private(struct subchannel *sch)
 	if (!private)
 		return ERR_PTR(-ENOMEM);
 
-	private->sch = sch;
 	mutex_init(&private->io_mutex);
 	private->state = VFIO_CCW_STATE_STANDBY;
 	INIT_LIST_HEAD(&private->crw);
@@ -395,7 +394,7 @@ static int vfio_ccw_chp_event(struct subchannel *sch,
 	if (!private || !mask)
 		return 0;
 
-	trace_vfio_ccw_chp_event(private->sch->schid, mask, event);
+	trace_vfio_ccw_chp_event(sch->schid, mask, event);
 	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: mask=0x%x event=%d\n",
 			   sch->schid.cssid,
 			   sch->schid.ssid, sch->schid.sch_no,

drivers/s390/cio/vfio_ccw_fsm.c

@@ -18,15 +18,13 @@
 
 static int fsm_io_helper(struct vfio_ccw_private *private)
 {
-	struct subchannel *sch;
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
 	union orb *orb;
 	int ccode;
 	__u8 lpm;
 	unsigned long flags;
 	int ret;
 
-	sch = private->sch;
-
 	spin_lock_irqsave(sch->lock, flags);
 
 	orb = cp_get_orb(&private->cp, (u32)(addr_t)sch, sch->lpm);
@@ -80,13 +78,11 @@ static int fsm_io_helper(struct vfio_ccw_private *private)
 
 static int fsm_do_halt(struct vfio_ccw_private *private)
 {
-	struct subchannel *sch;
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
 	unsigned long flags;
 	int ccode;
 	int ret;
 
-	sch = private->sch;
-
 	spin_lock_irqsave(sch->lock, flags);
 
 	VFIO_CCW_TRACE_EVENT(2, "haltIO");
@@ -121,13 +117,11 @@ static int fsm_do_halt(struct vfio_ccw_private *private)
 
 static int fsm_do_clear(struct vfio_ccw_private *private)
 {
-	struct subchannel *sch;
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
 	unsigned long flags;
 	int ccode;
 	int ret;
 
-	sch = private->sch;
-
 	spin_lock_irqsave(sch->lock, flags);
 
 	VFIO_CCW_TRACE_EVENT(2, "clearIO");
@@ -160,7 +154,7 @@ static int fsm_do_clear(struct vfio_ccw_private *private)
 static void fsm_notoper(struct vfio_ccw_private *private,
 			enum vfio_ccw_event event)
 {
-	struct subchannel *sch = private->sch;
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
 
 	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: notoper event %x state %x\n",
 			   sch->schid.cssid,
@@ -228,7 +222,7 @@ static void fsm_async_retry(struct vfio_ccw_private *private,
 static void fsm_disabled_irq(struct vfio_ccw_private *private,
 			     enum vfio_ccw_event event)
 {
-	struct subchannel *sch = private->sch;
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
 
 	/*
 	 * An interrupt in a disabled state means a previous disable was not
@@ -238,7 +232,9 @@ static void fsm_disabled_irq(struct vfio_ccw_private *private,
 }
 inline struct subchannel_id get_schid(struct vfio_ccw_private *p)
 {
-	return p->sch->schid;
+	struct subchannel *sch = to_subchannel(p->vdev.dev->parent);
+
+	return sch->schid;
 }
 
 /*
@@ -360,10 +356,11 @@ static void fsm_async_request(struct vfio_ccw_private *private,
 static void fsm_irq(struct vfio_ccw_private *private,
 		    enum vfio_ccw_event event)
 {
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
 	struct irb *irb = this_cpu_ptr(&cio_irb);
 
 	VFIO_CCW_TRACE_EVENT(6, "IRQ");
-	VFIO_CCW_TRACE_EVENT(6, dev_name(&private->sch->dev));
+	VFIO_CCW_TRACE_EVENT(6, dev_name(&sch->dev));
 
 	memcpy(&private->irb, irb, sizeof(*irb));
 
@@ -376,7 +373,7 @@ static void fsm_irq(struct vfio_ccw_private *private,
 static void fsm_open(struct vfio_ccw_private *private,
 		     enum vfio_ccw_event event)
 {
-	struct subchannel *sch = private->sch;
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
 	int ret;
 
 	spin_lock_irq(sch->lock);
@@ -397,7 +394,7 @@ static void fsm_open(struct vfio_ccw_private *private,
 static void fsm_close(struct vfio_ccw_private *private,
 		      enum vfio_ccw_event event)
 {
-	struct subchannel *sch = private->sch;
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
 	int ret;
 
 	spin_lock_irq(sch->lock);

drivers/s390/cio/vfio_ccw_ops.c

@@ -68,9 +68,9 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev)
 		return ret;
 
 	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: create\n",
-			   private->sch->schid.cssid,
-			   private->sch->schid.ssid,
-			   private->sch->schid.sch_no);
+			   sch->schid.cssid,
+			   sch->schid.ssid,
+			   sch->schid.sch_no);
 
 	ret = vfio_register_emulated_iommu_dev(&private->vdev);
 	if (ret)
@@ -107,9 +107,9 @@ static void vfio_ccw_mdev_remove(struct mdev_device *mdev)
 	struct vfio_ccw_private *private = dev_get_drvdata(&parent->dev);
 
 	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: remove\n",
-			   private->sch->schid.cssid,
-			   private->sch->schid.ssid,
-			   private->sch->schid.sch_no);
+			   sch->schid.cssid,
+			   sch->schid.ssid,
+			   sch->schid.sch_no);
 
 	vfio_unregister_group_dev(&private->vdev);
 

drivers/s390/cio/vfio_ccw_private.h

@@ -85,7 +85,6 @@ struct vfio_ccw_parent {
 /**
  * struct vfio_ccw_private
  * @vdev: Embedded VFIO device
- * @sch: pointer to the subchannel
  * @state: internal state of the device
  * @completion: synchronization helper of the I/O completion
  * @io_region: MMIO region to input/output I/O arguments/results
@@ -107,7 +106,6 @@ struct vfio_ccw_parent {
  */
 struct vfio_ccw_private {
 	struct vfio_device vdev;
-	struct subchannel	*sch;
 	int			state;
 	struct completion	*completion;
 	struct ccw_io_region	*io_region;
@@ -172,7 +170,10 @@ 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,
 				      enum vfio_ccw_event event)
 {
-	trace_vfio_ccw_fsm_event(private->sch->schid, private->state, event);
+	struct subchannel *sch = to_subchannel(private->vdev.dev->parent);
+
+	if (sch)
+		trace_vfio_ccw_fsm_event(sch->schid, private->state, event);
 	vfio_ccw_jumptable[private->state][event](private, event);
 }