On Wed, Apr 07, 2021 at 02:32:05PM +0800, Shiyang Ruan wrote:
> +static int dax_fault_cow_page(struct vm_fault *vmf, struct iomap *iomap,
> + loff_t pos, vm_fault_t *ret)
> +{
> + int error = 0;
> + unsigned long vaddr = vmf->address;
> + sector_t sector = dax_iomap_sector(iomap, pos);
> +
> + switch (iomap->type) {
> + case IOMAP_HOLE:
> + case IOMAP_UNWRITTEN:
> + clear_user_highpage(vmf->cow_page, vaddr);
> + break;
> + case IOMAP_MAPPED:
> + error = copy_cow_page_dax(iomap->bdev, iomap->dax_dev,
> + sector, vmf->cow_page, vaddr);
> + break;
> + default:
> + WARN_ON_ONCE(1);
> + error = -EIO;
> + break;
> + }
> +
> + if (error)
> + return error;
> +
> + __SetPageUptodate(vmf->cow_page);
> + *ret = finish_fault(vmf);
> + if (!*ret)
> + *ret = VM_FAULT_DONE_COW;
> + return 0;
> +}
...
> + error = dax_fault_cow_page(vmf, &iomap, pos, &ret);
> if (error)
> + ret = dax_fault_return(error);
> goto finish_iomap;
This seems unnecessarily complex. Why not return the vm_fault_t instead of
returning the errno and then converting it?
