vfio/pci: Extract duplicated code into macro

vfio_pci_core_do_io_rw() repeats the same code for multiple access
widths. Factor this out into a macro
Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Gerd Bayer <gbayer@linux.ibm.com>
Link: https://lore.kernel.org/r/20240619115847.1344875-2-gbayer@linux.ibm.comSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/pci/vfio_pci_rdwr.c

@@ -90,6 +90,40 @@ VFIO_IOREAD(8)
 VFIO_IOREAD(16)
 VFIO_IOREAD(32)
 
+#define VFIO_IORDWR(size)						\
+static int vfio_pci_iordwr##size(struct vfio_pci_core_device *vdev,\
+				bool iswrite, bool test_mem,		\
+				void __iomem *io, char __user *buf,	\
+				loff_t off, size_t *filled)		\
+{									\
+	u##size val;							\
+	int ret;							\
+									\
+	if (iswrite) {							\
+		if (copy_from_user(&val, buf, sizeof(val)))		\
+			return -EFAULT;					\
+									\
+		ret = vfio_pci_core_iowrite##size(vdev, test_mem,	\
+						  val, io + off);	\
+		if (ret)						\
+			return ret;					\
+	} else {							\
+		ret = vfio_pci_core_ioread##size(vdev, test_mem,	\
+						 &val, io + off);	\
+		if (ret)						\
+			return ret;					\
+									\
+		if (copy_to_user(buf, &val, sizeof(val)))		\
+			return -EFAULT;					\
+	}								\
+									\
+	*filled = sizeof(val);						\
+	return 0;							\
+}									\
+
+VFIO_IORDWR(8)
+VFIO_IORDWR(16)
+VFIO_IORDWR(32)
 /*
  * Read or write from an __iomem region (MMIO or I/O port) with an excluded
  * range which is inaccessible.  The excluded range drops writes and fills
@@ -115,71 +149,23 @@ ssize_t vfio_pci_core_do_io_rw(struct vfio_pci_core_device *vdev, bool test_mem,
 			fillable = 0;
 
 		if (fillable >= 4 && !(off % 4)) {
-			u32 val;
-
-			if (iswrite) {
-				if (copy_from_user(&val, buf, 4))
-					return -EFAULT;
-
-				ret = vfio_pci_core_iowrite32(vdev, test_mem,
-							      val, io + off);
-				if (ret)
-					return ret;
-			} else {
-				ret = vfio_pci_core_ioread32(vdev, test_mem,
-							     &val, io + off);
-				if (ret)
-					return ret;
-
-				if (copy_to_user(buf, &val, 4))
-					return -EFAULT;
-			}
+			ret = vfio_pci_iordwr32(vdev, iswrite, test_mem,
+						io, buf, off, &filled);
+			if (ret)
+				return ret;
 
-			filled = 4;
 		} else if (fillable >= 2 && !(off % 2)) {
-			u16 val;
-
-			if (iswrite) {
-				if (copy_from_user(&val, buf, 2))
-					return -EFAULT;
-
-				ret = vfio_pci_core_iowrite16(vdev, test_mem,
-							      val, io + off);
-				if (ret)
-					return ret;
-			} else {
-				ret = vfio_pci_core_ioread16(vdev, test_mem,
-							     &val, io + off);
-				if (ret)
-					return ret;
-
-				if (copy_to_user(buf, &val, 2))
-					return -EFAULT;
-			}
+			ret = vfio_pci_iordwr16(vdev, iswrite, test_mem,
+						io, buf, off, &filled);
+			if (ret)
+				return ret;
 
-			filled = 2;
 		} else if (fillable) {
-			u8 val;
-
-			if (iswrite) {
-				if (copy_from_user(&val, buf, 1))
-					return -EFAULT;
-
-				ret = vfio_pci_core_iowrite8(vdev, test_mem,
-							     val, io + off);
-				if (ret)
-					return ret;
-			} else {
-				ret = vfio_pci_core_ioread8(vdev, test_mem,
-							    &val, io + off);
-				if (ret)
-					return ret;
-
-				if (copy_to_user(buf, &val, 1))
-					return -EFAULT;
-			}
+			ret = vfio_pci_iordwr8(vdev, iswrite, test_mem,
+					       io, buf, off, &filled);
+			if (ret)
+				return ret;
 
-			filled = 1;
 		} else {
 			/* Fill reads with -1, drop writes */
 			filled = min(count, (size_t)(x_end - off));