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Commit f449b936 authored by Jan Kara's avatar Jan Kara Committed by Dan Williams
Browse files

dax: Finish fault completely when loading holes 



The only case when we do not finish the page fault completely is when we
are loading hole pages into a radix tree. Avoid this special case and
finish the fault in that case as well inside the DAX fault handler. It
will allow us for easier iomap handling.

Reviewed-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent e3fce68c

fs/dax.c

+18 −9
Original line number Original line Diff line number Diff line
@@ -539,15 +539,16 @@ int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 
 * otherwise it will simply fall out of the page cache under memory

 * otherwise it will simply fall out of the page cache under memory

 * pressure without ever having been dirtied.

 * pressure without ever having been dirtied.

 */

 */

static int dax_load_hole(struct address_space *mapping, void *entry,

static int dax_load_hole(struct address_space *mapping, void **entry,

			 struct vm_fault *vmf)

			 struct vm_fault *vmf)

{

{

	struct page *page;

	struct page *page;

	int ret;





	/* Hole page already exists? Return it...  */

	/* Hole page already exists? Return it...  */

	if (!radix_tree_exceptional_entry(entry)) {

	if (!radix_tree_exceptional_entry(*entry)) {

		vmf->page = entry;

		page = *entry;

		return VM_FAULT_LOCKED;

		goto out;

	}

	}





	/* This will replace locked radix tree entry with a hole page */

	/* This will replace locked radix tree entry with a hole page */
@@ -555,8 +556,17 @@ static int dax_load_hole(struct address_space *mapping, void *entry, 
				   vmf->gfp_mask | __GFP_ZERO);

				   vmf->gfp_mask | __GFP_ZERO);

	if (!page)

	if (!page)

		return VM_FAULT_OOM;

		return VM_FAULT_OOM;

 out:

	vmf->page = page;

	vmf->page = page;

	return VM_FAULT_LOCKED;

	ret = finish_fault(vmf);

	vmf->page = NULL;

	*entry = page;

	if (!ret) {

		/* Grab reference for PTE that is now referencing the page */

		get_page(page);

		return VM_FAULT_NOPAGE;

	}

	return ret;

}

}





static int copy_user_dax(struct block_device *bdev, sector_t sector, size_t size,

static int copy_user_dax(struct block_device *bdev, sector_t sector, size_t size,
@@ -1163,8 +1173,8 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, 
	case IOMAP_UNWRITTEN:

	case IOMAP_UNWRITTEN:

	case IOMAP_HOLE:

	case IOMAP_HOLE:

		if (!(vmf->flags & FAULT_FLAG_WRITE)) {

		if (!(vmf->flags & FAULT_FLAG_WRITE)) {

			vmf_ret = dax_load_hole(mapping, entry, vmf);

			vmf_ret = dax_load_hole(mapping, &entry, vmf);

			break;

			goto finish_iomap;

		}

		}

		/*FALLTHRU*/

		/*FALLTHRU*/

	default:

	default:
@@ -1185,7 +1195,6 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, 
		}

		}

	}

	}

 unlock_entry:

 unlock_entry:

	if (vmf_ret != VM_FAULT_LOCKED || error)

	put_locked_mapping_entry(mapping, vmf->pgoff, entry);

	put_locked_mapping_entry(mapping, vmf->pgoff, entry);

 out:

 out:

	if (error == -ENOMEM)

	if (error == -ENOMEM)