[PATCH v2 02/16] device/dax: update devdax to use mmap_prepare

[Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>]

The devdax driver does nothing special in its f_op->mmap hook, so
straightforwardly update it to use the mmap_prepare hook instead.

Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
---
 drivers/dax/device.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 2bb40a6060af..c2181439f925 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -13,8 +13,9 @@
 #include "dax-private.h"
 #include "bus.h"
 
-static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
-		const char *func)
+static int __check_vma(struct dev_dax *dev_dax, vm_flags_t vm_flags,
+		       unsigned long start, unsigned long end, struct file *file,
+		       const char *func)
 {
 	struct device *dev = &dev_dax->dev;
 	unsigned long mask;
@@ -23,7 +24,7 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
 		return -ENXIO;
 
 	/* prevent private mappings from being established */
-	if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
+	if ((vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
 		dev_info_ratelimited(dev,
 				"%s: %s: fail, attempted private mapping\n",
 				current->comm, func);
@@ -31,15 +32,15 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
 	}
 
 	mask = dev_dax->align - 1;
-	if (vma->vm_start & mask || vma->vm_end & mask) {
+	if (start & mask || end & mask) {
 		dev_info_ratelimited(dev,
 				"%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
-				current->comm, func, vma->vm_start, vma->vm_end,
+				current->comm, func, start, end,
 				mask);
 		return -EINVAL;
 	}
 
-	if (!vma_is_dax(vma)) {
+	if (!file_is_dax(file)) {
 		dev_info_ratelimited(dev,
 				"%s: %s: fail, vma is not DAX capable\n",
 				current->comm, func);
@@ -49,6 +50,13 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
 	return 0;
 }
 
+static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
+		     const char *func)
+{
+	return __check_vma(dev_dax, vma->vm_flags, vma->vm_start, vma->vm_end,
+			   vma->vm_file, func);
+}
+
 /* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
 __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
 		unsigned long size)
@@ -285,8 +293,9 @@ static const struct vm_operations_struct dax_vm_ops = {
 	.pagesize = dev_dax_pagesize,
 };
 
-static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
+static int dax_mmap_prepare(struct vm_area_desc *desc)
 {
+	struct file *filp = desc->file;
 	struct dev_dax *dev_dax = filp->private_data;
 	int rc, id;
 
@@ -297,13 +306,14 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
 	 * fault time.
 	 */
 	id = dax_read_lock();
-	rc = check_vma(dev_dax, vma, __func__);
+	rc = __check_vma(dev_dax, desc->vm_flags, desc->start, desc->end, filp,
+			 __func__);
 	dax_read_unlock(id);
 	if (rc)
 		return rc;
 
-	vma->vm_ops = &dax_vm_ops;
-	vm_flags_set(vma, VM_HUGEPAGE);
+	desc->vm_ops = &dax_vm_ops;
+	desc->vm_flags |= VM_HUGEPAGE;
 	return 0;
 }
 
@@ -377,7 +387,7 @@ static const struct file_operations dax_fops = {
 	.open = dax_open,
 	.release = dax_release,
 	.get_unmapped_area = dax_get_unmapped_area,
-	.mmap = dax_mmap,
+	.mmap_prepare = dax_mmap_prepare,
 	.fop_flags = FOP_MMAP_SYNC,
 };
 
-- 
2.51.0