dax: Allow dax_iomap_fault() to return pfn

jankara · djbw · commit 9a0dd4225143 · 2017-11-03T06:26:24.000-07:00
For synchronous page fault dax_iomap_fault() will need to return PFN
which will then need to be inserted into page tables after fsync()
completes. Add necessary parameter to dax_iomap_fault().

Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Ross Zwisler &lt;ross.zwisler@linux.intel.com&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
diff --git a/fs/dax.c b/fs/dax.c
@@ -1079,7 +1079,7 @@ static int dax_fault_return(int error)
 	return VM_FAULT_SIGBUS;
 }
 
-static int dax_iomap_pte_fault(struct vm_fault *vmf,
+static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
 			       const struct iomap_ops *ops)
 {
 	struct vm_area_struct *vma = vmf->vma;
@@ -1280,7 +1280,7 @@ static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
 	return VM_FAULT_FALLBACK;
 }
 
-static int dax_iomap_pmd_fault(struct vm_fault *vmf,
+static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 			       const struct iomap_ops *ops)
 {
 	struct vm_area_struct *vma = vmf->vma;
@@ -1425,7 +1425,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,
 	return result;
 }
 #else
-static int dax_iomap_pmd_fault(struct vm_fault *vmf,
+static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 			       const struct iomap_ops *ops)
 {
 	return VM_FAULT_FALLBACK;
@@ -1436,6 +1436,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,
  * dax_iomap_fault - handle a page fault on a DAX file
  * @vmf: The description of the fault
  * @pe_size: Size of the page to fault in
+ * @pfnp: PFN to insert for synchronous faults if fsync is required
  * @ops: Iomap ops passed from the file system
  *
  * When a page fault occurs, filesystems may call this helper in
@@ -1444,13 +1445,13 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,
  * successfully.
  */
 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
-		    const struct iomap_ops *ops)
+		    pfn_t *pfnp, const struct iomap_ops *ops)
 {
 	switch (pe_size) {
 	case PE_SIZE_PTE:
-		return dax_iomap_pte_fault(vmf, ops);
+		return dax_iomap_pte_fault(vmf, pfnp, ops);
 	case PE_SIZE_PMD:
-		return dax_iomap_pmd_fault(vmf, ops);
+		return dax_iomap_pmd_fault(vmf, pfnp, ops);
 	default:
 		return VM_FAULT_FALLBACK;
 	}
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
@@ -99,7 +99,7 @@ static int ext2_dax_fault(struct vm_fault *vmf)
 	}
 	down_read(&ei->dax_sem);
 
-	ret = dax_iomap_fault(vmf, PE_SIZE_PTE, &ext2_iomap_ops);
+	ret = dax_iomap_fault(vmf, PE_SIZE_PTE, NULL, &ext2_iomap_ops);
 
 	up_read(&ei->dax_sem);
 	if (vmf->flags & FAULT_FLAG_WRITE)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
@@ -306,7 +306,7 @@ static int ext4_dax_huge_fault(struct vm_fault *vmf,
 		down_read(&EXT4_I(inode)->i_mmap_sem);
 	}
 	if (!IS_ERR(handle))
-		result = dax_iomap_fault(vmf, pe_size, &ext4_iomap_ops);
+		result = dax_iomap_fault(vmf, pe_size, NULL, &ext4_iomap_ops);
 	else
 		result = VM_FAULT_SIGBUS;
 	if (write) {
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
@@ -1040,7 +1040,7 @@ __xfs_filemap_fault(
 
 	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
 	if (IS_DAX(inode)) {
-		ret = dax_iomap_fault(vmf, pe_size, &xfs_iomap_ops);
+		ret = dax_iomap_fault(vmf, pe_size, NULL, &xfs_iomap_ops);
 	} else {
 		if (write_fault)
 			ret = iomap_page_mkwrite(vmf, &xfs_iomap_ops);
@@ -1111,7 +1111,7 @@ xfs_filemap_pfn_mkwrite(
 	if (vmf->pgoff >= size)
 		ret = VM_FAULT_SIGBUS;
 	else if (IS_DAX(inode))
-		ret = dax_iomap_fault(vmf, PE_SIZE_PTE, &xfs_iomap_ops);
+		ret = dax_iomap_fault(vmf, PE_SIZE_PTE, NULL, &xfs_iomap_ops);
 	xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
 	sb_end_pagefault(inode->i_sb);
 	return ret;
diff --git a/include/linux/dax.h b/include/linux/dax.h
@@ -95,7 +95,7 @@ bool dax_write_cache_enabled(struct dax_device *dax_dev);
 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
 		const struct iomap_ops *ops);
 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
-		    const struct iomap_ops *ops);
+		    pfn_t *pfnp, const struct iomap_ops *ops);
 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 				      pgoff_t index);

Original file line number	Diff line number	Diff line change
`@@ -1079,7 +1079,7 @@ static int dax_fault_return(int error)`
`1079`	`1079`	`return VM_FAULT_SIGBUS;`
`1080`	`1080`	`}`
`1081`	`1081`
`1082`		`-static int dax_iomap_pte_fault(struct vm_fault *vmf,`
	`1082`	`+static int dax_iomap_pte_fault(struct vm_fault vmf, pfn_t pfnp,`
`1083`	`1083`	`const struct iomap_ops *ops)`
`1084`	`1084`	`{`
`1085`	`1085`	`struct vm_area_struct *vma = vmf->vma;`
`@@ -1280,7 +1280,7 @@ static int dax_pmd_load_hole(struct vm_fault vmf, struct iomap iomap,`
`1280`	`1280`	`return VM_FAULT_FALLBACK;`
`1281`	`1281`	`}`
`1282`	`1282`
`1283`		`-static int dax_iomap_pmd_fault(struct vm_fault *vmf,`
	`1283`	`+static int dax_iomap_pmd_fault(struct vm_fault vmf, pfn_t pfnp,`
`1284`	`1284`	`const struct iomap_ops *ops)`
`1285`	`1285`	`{`
`1286`	`1286`	`struct vm_area_struct *vma = vmf->vma;`
`@@ -1425,7 +1425,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,`
`1425`	`1425`	`return result;`
`1426`	`1426`	`}`
`1427`	`1427`	`#else`
`1428`		`-static int dax_iomap_pmd_fault(struct vm_fault *vmf,`
	`1428`	`+static int dax_iomap_pmd_fault(struct vm_fault vmf, pfn_t pfnp,`
`1429`	`1429`	`const struct iomap_ops *ops)`
`1430`	`1430`	`{`
`1431`	`1431`	`return VM_FAULT_FALLBACK;`
`@@ -1436,6 +1436,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,`
`1436`	`1436`	`* dax_iomap_fault - handle a page fault on a DAX file`
`1437`	`1437`	`* @vmf: The description of the fault`
`1438`	`1438`	`* @pe_size: Size of the page to fault in`
	`1439`	`+ * @pfnp: PFN to insert for synchronous faults if fsync is required`
`1439`	`1440`	`* @ops: Iomap ops passed from the file system`
`1440`	`1441`	`*`
`1441`	`1442`	`* When a page fault occurs, filesystems may call this helper in`
`@@ -1444,13 +1445,13 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf,`
`1444`	`1445`	`* successfully.`
`1445`	`1446`	`*/`
`1446`	`1447`	`int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,`
`1447`		`- const struct iomap_ops *ops)`
	`1448`	`+ pfn_t pfnp, const struct iomap_ops ops)`
`1448`	`1449`	`{`
`1449`	`1450`	`switch (pe_size) {`
`1450`	`1451`	`case PE_SIZE_PTE:`
`1451`		`- return dax_iomap_pte_fault(vmf, ops);`
	`1452`	`+ return dax_iomap_pte_fault(vmf, pfnp, ops);`
`1452`	`1453`	`case PE_SIZE_PMD:`
`1453`		`- return dax_iomap_pmd_fault(vmf, ops);`
	`1454`	`+ return dax_iomap_pmd_fault(vmf, pfnp, ops);`
`1454`	`1455`	`default:`
`1455`	`1456`	`return VM_FAULT_FALLBACK;`
`1456`	`1457`	`}`
Original file line number	Diff line number	Diff line change
`@@ -99,7 +99,7 @@ static int ext2_dax_fault(struct vm_fault *vmf)`
`99`	`99`	`}`
`100`	`100`	`down_read(&ei->dax_sem);`
`101`	`101`
`102`		`- ret = dax_iomap_fault(vmf, PE_SIZE_PTE, &ext2_iomap_ops);`
	`102`	`+ ret = dax_iomap_fault(vmf, PE_SIZE_PTE, NULL, &ext2_iomap_ops);`
`103`	`103`
`104`	`104`	`up_read(&ei->dax_sem);`
`105`	`105`	`if (vmf->flags & FAULT_FLAG_WRITE)`
Original file line number	Diff line number	Diff line change
`@@ -306,7 +306,7 @@ static int ext4_dax_huge_fault(struct vm_fault *vmf,`
`306`	`306`	`down_read(&EXT4_I(inode)->i_mmap_sem);`
`307`	`307`	`}`
`308`	`308`	`if (!IS_ERR(handle))`
`309`		`- result = dax_iomap_fault(vmf, pe_size, &ext4_iomap_ops);`
	`309`	`+ result = dax_iomap_fault(vmf, pe_size, NULL, &ext4_iomap_ops);`
`310`	`310`	`else`
`311`	`311`	`result = VM_FAULT_SIGBUS;`
`312`	`312`	`if (write) {`