optee: allocate shared memory with alloc_pages_exact()

Allocate memory to share with the secure world using alloc_pages_exact()
instead of alloc_pages() for more efficient memory usage.

Reviewed-by: Sumit Garg <[email protected]>
Signed-off-by: Jens Wiklander <[email protected]>

drivers/tee/optee/core.c

@@ -26,24 +26,22 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
 						   size_t num_pages,
 						   unsigned long start))
 {
-	unsigned int order = get_order(size);
-	unsigned int nr_pages = 1 << order;
+	size_t nr_pages = roundup(size, PAGE_SIZE) / PAGE_SIZE;
 	struct page **pages;
-	struct page *page;
 	unsigned int i;
 	int rc = 0;
 
 	/*
 	 * Ignore alignment since this is already going to be page aligned
 	 * and there's no need for any larger alignment.
 	 */
-	page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
-	if (!page)
+	shm->kaddr = alloc_pages_exact(nr_pages * PAGE_SIZE,
+				       GFP_KERNEL | __GFP_ZERO);
+	if (!shm->kaddr)
 		return -ENOMEM;
 
-	shm->kaddr = page_address(page);
-	shm->paddr = page_to_phys(page);
-	shm->size = PAGE_SIZE << order;
+	shm->paddr = virt_to_phys(shm->kaddr);
+	shm->size = nr_pages * PAGE_SIZE;
 
 	pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL);
 	if (!pages) {
@@ -52,7 +50,7 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
 	}
 
 	for (i = 0; i < nr_pages; i++)
-		pages[i] = page + i;
+		pages[i] = virt_to_page((u8 *)shm->kaddr + i * PAGE_SIZE);
 
 	shm->pages = pages;
 	shm->num_pages = nr_pages;
@@ -66,7 +64,7 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
 
 	return 0;
 err:
-	free_pages((unsigned long)shm->kaddr, order);
+	free_pages_exact(shm->kaddr, shm->size);
 	shm->kaddr = NULL;
 	return rc;
 }
@@ -77,7 +75,7 @@ void optee_pool_op_free_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
 {
 	if (shm_unregister)
 		shm_unregister(shm->ctx, shm);
-	free_pages((unsigned long)shm->kaddr, get_order(shm->size));
+	free_pages_exact(shm->kaddr, shm->size);
 	shm->kaddr = NULL;
 	kfree(shm->pages);
 	shm->pages = NULL;