[PATCH 07/25] memremap: validate the pagemap type passed to devm_memremap_pages

[Christoph Hellwig <hch@lst.de>]

Most pgmap types are only supported when certain config options are
enabled.  Check for a type that is valid for the current configuration
before setting up the pagemap.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/memremap.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/kernel/memremap.c b/kernel/memremap.c
index 6e1970719dc2..6a2dd31a6250 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -157,6 +157,33 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 	pgprot_t pgprot = PAGE_KERNEL;
 	int error, nid, is_ram;
 
+	switch (pgmap->type) {
+	case MEMORY_DEVICE_PRIVATE:
+		if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
+			WARN(1, "Device private memory not supported\n");
+			return ERR_PTR(-EINVAL);
+		}
+		break;
+	case MEMORY_DEVICE_PUBLIC:
+		if (!IS_ENABLED(CONFIG_DEVICE_PUBLIC)) {
+			WARN(1, "Device public memory not supported\n");
+			return ERR_PTR(-EINVAL);
+		}
+		break;
+	case MEMORY_DEVICE_FS_DAX:
+		if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
+		    IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
+			WARN(1, "File system DAX not supported\n");
+			return ERR_PTR(-EINVAL);
+		}
+		break;
+	case MEMORY_DEVICE_PCI_P2PDMA:
+		break;
+	default:
+		WARN(1, "Invalid pgmap type %d\n", pgmap->type);
+		break;
+	}
+
 	if (!pgmap->ref || !pgmap->kill || !pgmap->cleanup) {
 		WARN(1, "Missing reference count teardown definition\n");
 		return ERR_PTR(-EINVAL);
-- 
2.20.1

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