[PATCH v9 06/12] vfio_pci: Update vfio_pci to use vfio_info_add_capability()

[Kirti Wankhede <kwankhede@nvidia.com>]

Update msix_sparse_mmap_cap() to use vfio_info_add_capability()
Update region type capability to use vfio_info_add_capability()
Can't split this commit for MSIx and region_type cap since there is a
common code which need to be updated for both the cases.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Change-Id: I52bb28c7875a6da5a79ddad1843e6088aff58a45
---
 drivers/vfio/pci/vfio_pci.c | 72 +++++++++++++++++----------------------------
 1 file changed, 27 insertions(+), 45 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index d624a527777f..1ec0565b48ea 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -556,12 +556,12 @@ static int vfio_pci_for_each_slot_or_bus(struct pci_dev *pdev,
 }
 
 static int msix_sparse_mmap_cap(struct vfio_pci_device *vdev,
+				struct vfio_region_info *info,
 				struct vfio_info_cap *caps)
 {
-	struct vfio_info_cap_header *header;
 	struct vfio_region_info_cap_sparse_mmap *sparse;
 	size_t end, size;
-	int nr_areas = 2, i = 0;
+	int nr_areas = 2, i = 0, ret;
 
 	end = pci_resource_len(vdev->pdev, vdev->msix_bar);
 
@@ -572,13 +572,10 @@ static int msix_sparse_mmap_cap(struct vfio_pci_device *vdev,
 
 	size = sizeof(*sparse) + (nr_areas * sizeof(*sparse->areas));
 
-	header = vfio_info_cap_add(caps, size,
-				   VFIO_REGION_INFO_CAP_SPARSE_MMAP, 1);
-	if (IS_ERR(header))
-		return PTR_ERR(header);
+	sparse = kzalloc(size, GFP_KERNEL);
+	if (!sparse)
+		return -ENOMEM;
 
-	sparse = container_of(header,
-			      struct vfio_region_info_cap_sparse_mmap, header);
 	sparse->nr_areas = nr_areas;
 
 	if (vdev->msix_offset & PAGE_MASK) {
@@ -594,26 +591,11 @@ static int msix_sparse_mmap_cap(struct vfio_pci_device *vdev,
 		i++;
 	}
 
-	return 0;
-}
-
-static int region_type_cap(struct vfio_pci_device *vdev,
-			   struct vfio_info_cap *caps,
-			   unsigned int type, unsigned int subtype)
-{
-	struct vfio_info_cap_header *header;
-	struct vfio_region_info_cap_type *cap;
-
-	header = vfio_info_cap_add(caps, sizeof(*cap),
-				   VFIO_REGION_INFO_CAP_TYPE, 1);
-	if (IS_ERR(header))
-		return PTR_ERR(header);
+	ret = vfio_info_add_capability(info, caps,
+				      VFIO_REGION_INFO_CAP_SPARSE_MMAP, sparse);
+	kfree(sparse);
 
-	cap = container_of(header, struct vfio_region_info_cap_type, header);
-	cap->type = type;
-	cap->subtype = subtype;
-
-	return 0;
+	return ret;
 }
 
 int vfio_pci_register_dev_region(struct vfio_pci_device *vdev,
@@ -704,7 +686,8 @@ static long vfio_pci_ioctl(void *device_data,
 			if (vdev->bar_mmap_supported[info.index]) {
 				info.flags |= VFIO_REGION_INFO_FLAG_MMAP;
 				if (info.index == vdev->msix_bar) {
-					ret = msix_sparse_mmap_cap(vdev, &caps);
+					ret = msix_sparse_mmap_cap(vdev, &info,
+								   &caps);
 					if (ret)
 						return ret;
 				}
@@ -752,6 +735,9 @@ static long vfio_pci_ioctl(void *device_data,
 
 			break;
 		default:
+		{
+			struct vfio_region_info_cap_type cap_type;
+
 			if (info.index >=
 			    VFIO_PCI_NUM_REGIONS + vdev->num_regions)
 				return -EINVAL;
@@ -762,27 +748,23 @@ static long vfio_pci_ioctl(void *device_data,
 			info.size = vdev->region[i].size;
 			info.flags = vdev->region[i].flags;
 
-			ret = region_type_cap(vdev, &caps,
-					      vdev->region[i].type,
-					      vdev->region[i].subtype);
+			cap_type.type = vdev->region[i].type;
+			cap_type.subtype = vdev->region[i].subtype;
+
+			ret = vfio_info_add_capability(&info, &caps,
+						      VFIO_REGION_INFO_CAP_TYPE,
+						      &cap_type);
 			if (ret)
 				return ret;
+
+		}
 		}
 
-		if (caps.size) {
-			info.flags |= VFIO_REGION_INFO_FLAG_CAPS;
-			if (info.argsz < sizeof(info) + caps.size) {
-				info.argsz = sizeof(info) + caps.size;
-				info.cap_offset = 0;
-			} else {
-				vfio_info_cap_shift(&caps, sizeof(info));
-				if (copy_to_user((void __user *)arg +
-						  sizeof(info), caps.buf,
-						  caps.size)) {
-					kfree(caps.buf);
-					return -EFAULT;
-				}
-				info.cap_offset = sizeof(info);
+		if (info.cap_offset) {
+			if (copy_to_user((void __user *)arg + info.cap_offset,
+					 caps.buf, caps.size)) {
+				kfree(caps.buf);
+				return -EFAULT;
 			}
 
 			kfree(caps.buf);
-- 
2.7.0