dax: check resource alignment at dax region/device create

All the extents of a dax-device must match the alignment of the region.
Otherwise, we are unable to guarantee fault semantics of a given page
size.  The region must be self-consistent itself as well.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c
index 0a7899d..03bb54f 100644 (file)
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -206,8 +206,11 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
 {
        struct dax_region *dax_region;
 
-       dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
+       if (!IS_ALIGNED(res->start, align)
+                       || !IS_ALIGNED(resource_size(res), align))
+               return NULL;
 
+       dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
        if (!dax_region)
                return NULL;
 
@@ -560,15 +563,29 @@ int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res,
 {
        struct device *parent = dax_region->dev;
        struct dax_dev *dax_dev;
+       int rc = 0, minor, i;
        struct device *dev;
        struct cdev *cdev;
-       int rc, minor;
        dev_t dev_t;
 
        dax_dev = kzalloc(sizeof(*dax_dev) + sizeof(*res) * count, GFP_KERNEL);
        if (!dax_dev)
                return -ENOMEM;
 
+       for (i = 0; i < count; i++) {
+               if (!IS_ALIGNED(res[i].start, dax_region->align)
+                               || !IS_ALIGNED(resource_size(&res[i]),
+                                       dax_region->align)) {
+                       rc = -EINVAL;
+                       break;
+               }
+               dax_dev->res[i].start = res[i].start;
+               dax_dev->res[i].end = res[i].end;
+       }
+
+       if (i < count)
+               goto err_id;
+
        dax_dev->id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL);
        if (dax_dev->id < 0) {
                rc = dax_dev->id;
@@ -601,7 +618,6 @@ int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res,
                goto err_cdev;
 
        /* from here on we're committed to teardown via dax_dev_release() */
-       memcpy(dax_dev->res, res, sizeof(*res) * count);
        dax_dev->num_resources = count;
        dax_dev->alive = true;
        dax_dev->region = dax_region;