vfio/ccw: Pass vfio_ccw_private not mdev_device to various functions

mdev_device should only be used in functions assigned to ops callbacks,
interior functions should use the struct vfio_ccw_private instead of
repeatedly trying to get it from the mdev.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v4-cea4f5bd2c00+b52-ccw_mdev_jgg@nvidia.comSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/s390/cio/vfio_ccw_ops.c

@@ -17,13 +17,11 @@
 
 #include "vfio_ccw_private.h"
 
-static int vfio_ccw_mdev_reset(struct mdev_device *mdev)
+static int vfio_ccw_mdev_reset(struct vfio_ccw_private *private)
 {
-	struct vfio_ccw_private *private;
 	struct subchannel *sch;
 	int ret;
 
-	private = dev_get_drvdata(mdev_parent_dev(mdev));
 	sch = private->sch;
 	/*
 	 * TODO:
@@ -61,7 +59,7 @@ static int vfio_ccw_mdev_notifier(struct notifier_block *nb,
 		if (!cp_iova_pinned(&private->cp, unmap->iova))
 			return NOTIFY_OK;
 
-		if (vfio_ccw_mdev_reset(private->mdev))
+		if (vfio_ccw_mdev_reset(private))
 			return NOTIFY_BAD;
 
 		cp_free(&private->cp);
@@ -201,7 +199,7 @@ static void vfio_ccw_mdev_close_device(struct mdev_device *mdev)
 
 	if ((private->state != VFIO_CCW_STATE_NOT_OPER) &&
 	    (private->state != VFIO_CCW_STATE_STANDBY)) {
-		if (!vfio_ccw_mdev_reset(mdev))
+		if (!vfio_ccw_mdev_reset(private))
 			private->state = VFIO_CCW_STATE_STANDBY;
 		/* The state will be NOT_OPER on error. */
 	}
@@ -311,12 +309,9 @@ static ssize_t vfio_ccw_mdev_write(struct mdev_device *mdev,
 	return -EINVAL;
 }
 
-static int vfio_ccw_mdev_get_device_info(struct vfio_device_info *info,
-					 struct mdev_device *mdev)
+static int vfio_ccw_mdev_get_device_info(struct vfio_ccw_private *private,
+					 struct vfio_device_info *info)
 {
-	struct vfio_ccw_private *private;
-
-	private = dev_get_drvdata(mdev_parent_dev(mdev));
 	info->flags = VFIO_DEVICE_FLAGS_CCW | VFIO_DEVICE_FLAGS_RESET;
 	info->num_regions = VFIO_CCW_NUM_REGIONS + private->num_regions;
 	info->num_irqs = VFIO_CCW_NUM_IRQS;
@@ -324,14 +319,12 @@ static int vfio_ccw_mdev_get_device_info(struct vfio_device_info *info,
 	return 0;
 }
 
-static int vfio_ccw_mdev_get_region_info(struct vfio_region_info *info,
-					 struct mdev_device *mdev,
+static int vfio_ccw_mdev_get_region_info(struct vfio_ccw_private *private,
+					 struct vfio_region_info *info,
 					 unsigned long arg)
 {
-	struct vfio_ccw_private *private;
 	int i;
 
-	private = dev_get_drvdata(mdev_parent_dev(mdev));
 	switch (info->index) {
 	case VFIO_CCW_CONFIG_REGION_INDEX:
 		info->offset = 0;
@@ -406,19 +399,16 @@ static int vfio_ccw_mdev_get_irq_info(struct vfio_irq_info *info)
 	return 0;
 }
 
-static int vfio_ccw_mdev_set_irqs(struct mdev_device *mdev,
+static int vfio_ccw_mdev_set_irqs(struct vfio_ccw_private *private,
 				  uint32_t flags,
 				  uint32_t index,
 				  void __user *data)
 {
-	struct vfio_ccw_private *private;
 	struct eventfd_ctx **ctx;
 
 	if (!(flags & VFIO_IRQ_SET_ACTION_TRIGGER))
 		return -EINVAL;
 
-	private = dev_get_drvdata(mdev_parent_dev(mdev));
-
 	switch (index) {
 	case VFIO_CCW_IO_IRQ_INDEX:
 		ctx = &private->io_trigger;
@@ -524,6 +514,8 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
 				   unsigned int cmd,
 				   unsigned long arg)
 {
+	struct vfio_ccw_private *private =
+		dev_get_drvdata(mdev_parent_dev(mdev));
 	int ret = 0;
 	unsigned long minsz;
 
@@ -540,7 +532,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
 		if (info.argsz < minsz)
 			return -EINVAL;
 
-		ret = vfio_ccw_mdev_get_device_info(&info, mdev);
+		ret = vfio_ccw_mdev_get_device_info(private, &info);
 		if (ret)
 			return ret;
 
@@ -558,7 +550,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
 		if (info.argsz < minsz)
 			return -EINVAL;
 
-		ret = vfio_ccw_mdev_get_region_info(&info, mdev, arg);
+		ret = vfio_ccw_mdev_get_region_info(private, &info, arg);
 		if (ret)
 			return ret;
 
@@ -603,10 +595,11 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
 			return ret;
 
 		data = (void __user *)(arg + minsz);
-		return vfio_ccw_mdev_set_irqs(mdev, hdr.flags, hdr.index, data);
+		return vfio_ccw_mdev_set_irqs(private, hdr.flags, hdr.index,
+					      data);
 	}
 	case VFIO_DEVICE_RESET:
-		return vfio_ccw_mdev_reset(mdev);
+		return vfio_ccw_mdev_reset(private);
 	default:
 		return -ENOTTY;
 	}