vfio: Split the container logic into vfio_container_attach_group()

This splits up the ioctl of vfio_group_ioctl_set_container() so it
determines the type of file then invokes a type specific attachment
function. Future patches will add iommufd to this function as an
alternative type.

A following patch will move the vfio_container functions to their own .c
file.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/3-v3-297af71838d2+b9-vfio_container_split_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 3d88131..879c5d2 100644 (file)
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -1097,40 +1097,29 @@ out_unlock:
        return ret;
 }
 
-static int vfio_group_ioctl_set_container(struct vfio_group *group,
-                                         int __user *arg)
+static struct vfio_container *vfio_container_from_file(struct file *file)
 {
-       struct fd f;
        struct vfio_container *container;
-       struct vfio_iommu_driver *driver;
-       int container_fd;
-       int ret = 0;
-
-       if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO))
-               return -EPERM;
-
-       if (get_user(container_fd, arg))
-               return -EFAULT;
-       if (container_fd < 0)
-               return -EINVAL;
-       f = fdget(container_fd);
-       if (!f.file)
-               return -EBADF;
 
        /* Sanity check, is this really our fd? */
-       if (f.file->f_op != &vfio_fops) {
-               ret = -EINVAL;
-               goto out_fdput;
-       }
-       container = f.file->private_data;
+       if (file->f_op != &vfio_fops)
+               return NULL;
+
+       container = file->private_data;
        WARN_ON(!container); /* fget ensures we don't race vfio_release */
+       return container;
+}
 
-       down_write(&group->group_rwsem);
+static int vfio_container_attach_group(struct vfio_container *container,
+                                      struct vfio_group *group)
+{
+       struct vfio_iommu_driver *driver;
+       int ret = 0;
 
-       if (group->container || WARN_ON(group->container_users)) {
-               ret = -EINVAL;
-               goto out_unlock_group;
-       }
+       lockdep_assert_held_write(&group->group_rwsem);
+
+       if (group->type == VFIO_NO_IOMMU && !capable(CAP_SYS_RAWIO))
+               return -EPERM;
 
        down_write(&container->group_lock);
 
@@ -1142,7 +1131,7 @@ static int vfio_group_ioctl_set_container(struct vfio_group *group,
        }
 
        if (group->type == VFIO_IOMMU) {
-               ret = iommu_group_claim_dma_owner(group->iommu_group, f.file);
+               ret = iommu_group_claim_dma_owner(group->iommu_group, group);
                if (ret)
                        goto out_unlock_container;
        }
@@ -1170,9 +1159,38 @@ static int vfio_group_ioctl_set_container(struct vfio_group *group,
 
 out_unlock_container:
        up_write(&container->group_lock);
-out_unlock_group:
+       return ret;
+}
+
+static int vfio_group_ioctl_set_container(struct vfio_group *group,
+                                         int __user *arg)
+{
+       struct vfio_container *container;
+       struct fd f;
+       int ret;
+       int fd;
+
+       if (get_user(fd, arg))
+               return -EFAULT;
+
+       f = fdget(fd);
+       if (!f.file)
+               return -EBADF;
+
+       down_write(&group->group_rwsem);
+       if (group->container || WARN_ON(group->container_users)) {
+               ret = -EINVAL;
+               goto out_unlock;
+       }
+       container = vfio_container_from_file(f.file);
+       ret = -EINVAL;
+       if (container) {
+               ret = vfio_container_attach_group(container, group);
+               goto out_unlock;
+       }
+
+out_unlock:
        up_write(&group->group_rwsem);
-out_fdput:
        fdput(f);
        return ret;
 }