[PATCH net-next v4 2/3] selftests/net: ncdevmem: add -b option to set rx-buf-size on bind
From: Bobby Eshleman <hidden>
Date: 2026-07-01 19:22:38
Also in:
dri-devel, linux-kselftest, linux-media, lkml
Subsystem:
kernel selftest framework, networking drivers, the rest · Maintainers:
Shuah Khan, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Bobby Eshleman <redacted> Add -b <bytes> to request a non-default niov size via NETDEV_A_DMABUF_RX_BUF_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. Add CONFIG_HUGETLBFS=y to drivers/net/hw/config so the new path is reachable in the CI kernels built for these tests. Signed-off-by: Bobby Eshleman <redacted> Acked-by: Stanislav Fomichev <sdf@fomichev.me> --- 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 d96e8a3b5a65..a16e55af51ee 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_buf_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_buf_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_buf_size) + netdev_bind_rx_req_set_rx_buf_size(req, rx_buf_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_buf_size: %s", optarg); + return 1; + } + rx_buf_size = val; + break; + } case '?': fprintf(stderr, "unknown option: %c\n", optopt); break;
--
2.53.0-Meta