[RFC 13/16] vfio/mlx5: Explicitly store page list

[Leon Romanovsky]

From: Leon Romanovsky <leonro at nvidia.com>

As a preparation to removal scatter-gather table and unifying
receive and send list, explicitly store page list.

Signed-off-by: Leon Romanovsky <leonro at nvidia.com>
---
 drivers/vfio/pci/mlx5/cmd.c  |  1 +
 drivers/vfio/pci/mlx5/cmd.h  |  1 +
 drivers/vfio/pci/mlx5/main.c | 35 +++++++++++++++++------------------
 3 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/drivers/vfio/pci/mlx5/cmd.c b/drivers/vfio/pci/mlx5/cmd.c
index 44762980fcb9..5e2103042d9b 100644
--- a/drivers/vfio/pci/mlx5/cmd.c
+++ b/drivers/vfio/pci/mlx5/cmd.c
@@ -411,6 +411,7 @@ void mlx5vf_free_data_buffer(struct mlx5_vhca_data_buffer *buf)
 	for_each_sgtable_page(&buf->table.sgt, &sg_iter, 0)
 		__free_page(sg_page_iter_page(&sg_iter));
 	sg_free_append_table(&buf->table);
+	kvfree(buf->page_list);
 	kfree(buf);
 }
 
diff --git a/drivers/vfio/pci/mlx5/cmd.h b/drivers/vfio/pci/mlx5/cmd.h
index 83728c0669e7..815fcb54494d 100644
--- a/drivers/vfio/pci/mlx5/cmd.h
+++ b/drivers/vfio/pci/mlx5/cmd.h
@@ -57,6 +57,7 @@ struct mlx5_vf_migration_header {
 };
 
 struct mlx5_vhca_data_buffer {
+	struct page **page_list;
 	struct sg_append_table table;
 	loff_t start_pos;
 	u64 length;
diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
index b11b1c27d284..7ffe24693a55 100644
--- a/drivers/vfio/pci/mlx5/main.c
+++ b/drivers/vfio/pci/mlx5/main.c
@@ -69,44 +69,43 @@ int mlx5vf_add_migration_pages(struct mlx5_vhca_data_buffer *buf,
 			       unsigned int npages)
 {
 	unsigned int to_alloc = npages;
+	size_t old_size, new_size;
 	struct page **page_list;
 	unsigned long filled;
 	unsigned int to_fill;
 	int ret;
 
-	to_fill = min_t(unsigned int, npages, PAGE_SIZE / sizeof(*page_list));
-	page_list = kvzalloc(to_fill * sizeof(*page_list), GFP_KERNEL_ACCOUNT);
+	to_fill = min_t(unsigned int, npages,
+			PAGE_SIZE / sizeof(*buf->page_list));
+	old_size = buf->npages * sizeof(*buf->page_list);
+	new_size = old_size + to_fill * sizeof(*buf->page_list);
+	page_list = kvrealloc(buf->page_list, old_size, new_size,
+			      GFP_KERNEL_ACCOUNT | __GFP_ZERO);
 	if (!page_list)
 		return -ENOMEM;
 
+	buf->page_list = page_list;
+
 	do {
 		filled = alloc_pages_bulk_array(GFP_KERNEL_ACCOUNT, to_fill,
-						page_list);
-		if (!filled) {
-			ret = -ENOMEM;
-			goto err;
-		}
+						buf->page_list + buf->npages);
+		if (!filled)
+			return -ENOMEM;
+
 		to_alloc -= filled;
 		ret = sg_alloc_append_table_from_pages(
-			&buf->table, page_list, filled, 0,
+			&buf->table, buf->page_list + buf->npages, filled, 0,
 			filled << PAGE_SHIFT, UINT_MAX, SG_MAX_SINGLE_ALLOC,
 			GFP_KERNEL_ACCOUNT);
-
 		if (ret)
-			goto err;
+			return ret;
+
 		buf->npages += filled;
-		/* clean input for another bulk allocation */
-		memset(page_list, 0, filled * sizeof(*page_list));
 		to_fill = min_t(unsigned int, to_alloc,
-				PAGE_SIZE / sizeof(*page_list));
+				PAGE_SIZE / sizeof(*buf->page_list));
 	} while (to_alloc > 0);
 
-	kvfree(page_list);
 	return 0;
-
-err:
-	kvfree(page_list);
-	return ret;
 }
 
 static void mlx5vf_disable_fd(struct mlx5_vf_migration_file *migf)
-- 
2.44.0