[PATCH review-only 14/17] io_uring/zcrx: pass area_id to __zcrx_create_area()

[Pavel Begunkov <asml.silence@gmail.com>]

Instead of generating an area id inside of __zcrx_create_area(), let the
caller to pass it. It needs the id to derive the user token, and we
might need to know it before creating and publishing the area.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/zcrx.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 474ffc217b0b..3f61f942c393 100644
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -44,6 +44,11 @@ static inline u64 zcrx_area_id_to_token(u32 area_id)
 	return (u64)area_id << IORING_ZCRX_AREA_SHIFT;
 }
 
+static inline u32 zcrx_next_area_id(struct io_zcrx_ifq *zcrx)
+{
+	return zcrx->nr_areas;
+}
+
 static inline struct io_zcrx_ifq *io_pp_to_ifq(struct page_pool *pp)
 {
 	return pp->mp_priv;
@@ -472,6 +477,8 @@ static int io_zcrx_append_area(struct io_zcrx_ifq *ifq,
 
 	if (WARN_ON_ONCE(ifq->kern_readable != kern_readable))
 		return -EINVAL;
+	if (WARN_ON_ONCE(area->area_id != zcrx_next_area_id(ifq)))
+		return -EINVAL;
 
 	old_areas = ifq->areas;
 	old_nr = ifq->nr_areas;
@@ -494,9 +501,10 @@ static int io_zcrx_append_area(struct io_zcrx_ifq *ifq,
 }
 
 static int __zcrx_create_area(struct io_zcrx_ifq *ifq,
-			       struct io_uring_zcrx_area_reg *area_reg,
+			       const struct io_uring_zcrx_area_reg *area_reg,
 			       struct io_zcrx_area **res_area,
-			       u32 rx_buf_len)
+			       u32 rx_buf_len,
+			       u32 area_id)
 {
 	int buf_size_shift = PAGE_SHIFT;
 	struct io_zcrx_area *area;
@@ -565,9 +573,7 @@ static int __zcrx_create_area(struct io_zcrx_ifq *ifq,
 	}
 
 	area->free_count = nr_iovs;
-	/* we're only supporting one area per ifq for now */
-	area->area_id = 0;
-	area_reg->rq_area_token = zcrx_area_id_to_token(area->area_id);
+	area->area_id = area_id;
 	*res_area = area;
 	return 0;
 err:
@@ -583,9 +589,12 @@ static int io_zcrx_create_area(struct io_zcrx_ifq *ifq,
 			       struct io_uring_zcrx_ifq_reg *reg)
 {
 	struct io_zcrx_area *area;
+	u32 id = zcrx_next_area_id(ifq);
 	int ret;
 
-	ret = __zcrx_create_area(ifq, area_reg, &area, reg->rx_buf_len);
+	area_reg->rq_area_token = zcrx_area_id_to_token(id);
+
+	ret = __zcrx_create_area(ifq, area_reg, &area, reg->rx_buf_len, id);
 	if (ret)
 		return ret;
 
-- 
2.54.0