[PATCH net-next v8 2/3] selftests/net: ncdevmem: add -b option to set rx-page-size on bind

From: Bobby Eshleman <[email protected]>

Add -b <bytes> to request a non-default niov size via
NETDEV_A_DMABUF_RX_PAGE_SIZE. When the value exceeds PAGE_SIZE,
udmabuf_alloc() switches to an MFD_HUGETLB-backed memfd so each 2 MB
hugepage produces one naturally-aligned sg entry.

Acked-by: Stanislav Fomichev <[email protected]>
Reviewed-by: Nikolay Aleksandrov <[email protected]>
Signed-off-by: Bobby Eshleman <[email protected]>
---
 tools/testing/selftests/drivers/net/hw/ncdevmem.c | 36 +++++++++++++++++++++--
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
index ffe1d5c1fa4e..918e3b51f3b8 100644
--- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
+++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
@@ -40,6 +40,7 @@
 
 #include <linux/uio.h>
 #include <stdarg.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -61,6 +62,7 @@
 #include <sys/time.h>
 
 #include <linux/memfd.h>
+#include <sys/param.h>
 #include <linux/dma-buf.h>
 #include <linux/errqueue.h>
 #include <linux/udmabuf.h>
@@ -79,6 +81,7 @@
 #define PAGE_SHIFT 12
 #define TEST_PREFIX "ncdevmem"
 #define NUM_PAGES 16000
+#define MB(x) ((x) << 20)
 
 #ifndef MSG_SOCK_DEVMEM
 #define MSG_SOCK_DEVMEM 0x2000000
@@ -100,6 +103,7 @@ static unsigned int dmabuf_id;
 static uint32_t tx_dmabuf_id;
 static int waittime_ms = 500;
 static bool fail_on_linear;
+static uint32_t rx_page_size;
 
 /* System state loaded by current_config_load() */
 #define MAX_FLOWS	8
@@ -142,6 +146,7 @@ static struct memory_buffer *udmabuf_alloc(size_t size)
 {
 	struct udmabuf_create create;
 	struct memory_buffer *ctx;
+	unsigned int memfd_flags;
 	int ret;
 
 	ctx = malloc(sizeof(*ctx));
@@ -156,9 +161,14 @@ static struct memory_buffer *udmabuf_alloc(size_t size)
 		goto err_free_ctx;
 	}
 
-	ctx->memfd = memfd_create("udmabuf-test", MFD_ALLOW_SEALING);
+	memfd_flags = MFD_ALLOW_SEALING;
+	if (rx_page_size > getpagesize())
+		memfd_flags |= MFD_HUGETLB | MFD_HUGE_2MB;
+
+	ctx->memfd = memfd_create("udmabuf-test", memfd_flags);
 	if (ctx->memfd < 0) {
-		pr_err("[skip,no-memfd]");
+		pr_err("[skip,no-memfd%s]",
+		       (memfd_flags & MFD_HUGETLB) ? " (need hugepages)" : "");
 		goto err_close_dev;
 	}
 
@@ -168,6 +178,11 @@ static struct memory_buffer *udmabuf_alloc(size_t size)
 		goto err_close_memfd;
 	}
 
+	if (memfd_flags & MFD_HUGETLB) {
+		size = roundup(size, MB(2));
+		ctx->size = size;
+	}
+
 	ret = ftruncate(ctx->memfd, size);
 	if (ret == -1) {
 		pr_err("[FAIL,memfd-truncate]");
@@ -699,6 +714,8 @@ static int bind_rx_queue(unsigned int ifindex, unsigned int dmabuf_fd,
 	netdev_bind_rx_req_set_ifindex(req, ifindex);
 	netdev_bind_rx_req_set_fd(req, dmabuf_fd);
 	__netdev_bind_rx_req_set_queues(req, queues, n_queue_index);
+	if (rx_page_size)
+		netdev_bind_rx_req_set_rx_page_size(req, rx_page_size);
 
 	rsp = netdev_bind_rx(*ys, req);
 	if (!rsp) {
@@ -1411,7 +1428,7 @@ int main(int argc, char *argv[])
 	int is_server = 0, opt;
 	int ret, err = 1;
 
-	while ((opt = getopt(argc, argv, "Lls:c:p:v:q:t:f:z:n")) != -1) {
+	while ((opt = getopt(argc, argv, "Lls:c:p:v:q:t:f:z:nb:")) != -1) {
 		switch (opt) {
 		case 'L':
 			fail_on_linear = true;
@@ -1446,6 +1463,19 @@ int main(int argc, char *argv[])
 		case 'n':
 			skip_config = 1;
 			break;
+		case 'b': {
+			unsigned long val;
+
+			errno = 0;
+			val = strtoul(optarg, NULL, 0);
+			if ((val == ULONG_MAX && errno == ERANGE) ||
+			    val > UINT32_MAX) {
+				pr_err("invalid rx_page_size: %s", optarg);
+				return 1;
+			}
+			rx_page_size = val;
+			break;
+		}
 		case '?':
 			fprintf(stderr, "unknown option: %c\n", optopt);
 			break;

-- 
2.53.0-Meta