[RFC 4/6] io_uring/zcrx: don't pass ifq_reg for for area creation

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

We might want to create an area without having an instance of struct
io_uring_zcrx_ifq_reg. Extract a helper that doesn't have the ifq
registration structure as an argument but takes the buf length
explicitly.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/zcrx.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 0ec491587a36..0551b05d53ee 100644
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -466,21 +466,22 @@ static int io_zcrx_append_area(struct io_zcrx_ifq *ifq,
 	return 0;
 }
 
-static int io_zcrx_create_area(struct io_zcrx_ifq *ifq,
+static int __zcrx_create_area(struct io_zcrx_ifq *ifq,
 			       struct io_uring_zcrx_area_reg *area_reg,
-			       struct io_uring_zcrx_ifq_reg *reg)
+			       u32 rx_buf_len)
 {
 	int buf_size_shift = PAGE_SHIFT;
 	struct io_zcrx_area *area;
 	unsigned nr_iovs;
 	int i, ret;
 
-	if (reg->rx_buf_len) {
-		if (!is_power_of_2(reg->rx_buf_len) ||
-		     reg->rx_buf_len < PAGE_SIZE)
+	if (rx_buf_len) {
+		if (!is_power_of_2(rx_buf_len) || rx_buf_len < PAGE_SIZE)
 			return -EINVAL;
-		buf_size_shift = ilog2(reg->rx_buf_len);
+		buf_size_shift = ilog2(rx_buf_len);
 	}
+	if (WARN_ON_ONCE(ifq->niov_shift))
+		return -EINVAL;
 	if (!ifq->dev && buf_size_shift != PAGE_SHIFT)
 		return -EOPNOTSUPP;
 
@@ -550,6 +551,13 @@ static int io_zcrx_create_area(struct io_zcrx_ifq *ifq,
 	return ret;
 }
 
+static int io_zcrx_create_area(struct io_zcrx_ifq *ifq,
+			       struct io_uring_zcrx_area_reg *area_reg,
+			       struct io_uring_zcrx_ifq_reg *reg)
+{
+	return __zcrx_create_area(ifq, area_reg, reg->rx_buf_len);
+}
+
 static struct io_zcrx_ifq *io_zcrx_ifq_alloc(struct io_ring_ctx *ctx)
 {
 	struct io_zcrx_ifq *ifq;
-- 
2.53.0