[PATCH v3] tee: make tee_shm_register_kernel_buf vmalloc supported

[Phil Chang]

In some low-memory devices, it's hard to aquire large-orders pages,
this patch allowed user using scatter pages to register shm.

Signed-off-by: Phil Chang <phil.chang at mediatek.com>
---

Changelog
	v2 -> v3: use the "n" variable to walk through "page_count"

 drivers/tee/optee/call.c |  2 +-
 drivers/tee/tee_shm.c    | 37 ++++++++++++++++++++++++++-----------
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index bd49ec934060..2082e632adff 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -362,7 +362,7 @@ int optee_check_mem_type(unsigned long start, size_t num_pages)
 	 * Allow kernel address to register with OP-TEE as kernel
 	 * pages are configured as normal memory only.
 	 */
-	if (virt_addr_valid(start))
+	if (virt_addr_valid(start) || is_vmalloc_addr((void *)start))
 		return 0;
 
 	mmap_read_lock(mm);
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index f31e29e8f1ca..1412adad9397 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -23,21 +23,36 @@ static void shm_put_kernel_pages(struct page **pages, size_t page_count)
 static int shm_get_kernel_pages(unsigned long start, size_t page_count,
 				struct page **pages)
 {
-	struct kvec *kiov;
-	size_t n;
 	int rc;
+	size_t n;
 
-	kiov = kcalloc(page_count, sizeof(*kiov), GFP_KERNEL);
-	if (!kiov)
-		return -ENOMEM;
+	if (is_vmalloc_addr((void *)start)) {
+		struct page *page;
 
-	for (n = 0; n < page_count; n++) {
-		kiov[n].iov_base = (void *)(start + n * PAGE_SIZE);
-		kiov[n].iov_len = PAGE_SIZE;
-	}
+		for (n = 0; n < page_count; n++) {
+			page = vmalloc_to_page((void *)(start + PAGE_SIZE * n));
+			if (!page)
+				return -ENOMEM;
+
+			get_page(page);
+			pages[n] = page;
+		}
+		rc = page_count;
+	} else {
+		struct kvec *kiov;
 
-	rc = get_kernel_pages(kiov, page_count, 0, pages);
-	kfree(kiov);
+		kiov = kcalloc(page_count, sizeof(*kiov), GFP_KERNEL);
+		if (!kiov)
+			return -ENOMEM;
+
+		for (n = 0; n < page_count; n++) {
+			kiov[n].iov_base = (void *)(start + n * PAGE_SIZE);
+			kiov[n].iov_len = PAGE_SIZE;
+		}
+
+		rc = get_kernel_pages(kiov, page_count, 0, pages);
+		kfree(kiov);
+	}
 
 	return rc;
 }
-- 
2.25.1