devm_memremap: Fix error value when memremap failed

devm_memremap() returns an ERR_PTR() value in case of error.
However, it returns NULL when memremap() failed.  This causes
the caller, such as the pmem driver, to proceed and oops later.

Change devm_memremap() to return ERR_PTR(-ENXIO) when memremap()
failed.

Signed-off-by: Toshi Kani <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: <[email protected]>
Reviewed-by: Ross Zwisler <[email protected]>
Signed-off-by: Dan Williams <[email protected]>

kernel/memremap.c

@@ -136,8 +136,10 @@ void *devm_memremap(struct device *dev, resource_size_t offset,
 	if (addr) {
 		*ptr = addr;
 		devres_add(dev, ptr);
-	} else
+	} else {
 		devres_free(ptr);
+		return ERR_PTR(-ENXIO);
+	}
 
 	return addr;
 }