Commit d41905b3 authored by Maciej Fijalkowski's avatar Maciej Fijalkowski Committed by Daniel Borkmann
Browse files

selftests/xsk: Read current MAX_SKB_FRAGS from sysctl knob 



Currently, xskxceiver assumes that MAX_SKB_FRAGS value is always 17
which is not true - since the introduction of BIG TCP this can now take
any value between 17 to 45 via CONFIG_MAX_SKB_FRAGS.

Adjust the TOO_MANY_FRAGS test case to read the currently configured
MAX_SKB_FRAGS value by reading it from /proc/sys/net/core/max_skb_frags.
If running system does not provide that sysctl file then let us try
running the test with a default value.

Signed-off-by: default avatarMaciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20240910124129.289874-1-maciej.fijalkowski@intel.com
parent 6b083650

tools/testing/selftests/bpf/xskxceiver.c

+38 −5
Original line number Diff line number Diff line
@@ -324,6 +324,25 @@ static bool ifobj_zc_avail(struct ifobject *ifobject) 
	return zc_avail;

}



#define MAX_SKB_FRAGS_PATH "/proc/sys/net/core/max_skb_frags"

static unsigned int get_max_skb_frags(void)

{

	unsigned int max_skb_frags = 0;

	FILE *file;



	file = fopen(MAX_SKB_FRAGS_PATH, "r");

	if (!file) {

		ksft_print_msg("Error opening %s\n", MAX_SKB_FRAGS_PATH);

		return 0;

	}



	if (fscanf(file, "%u", &max_skb_frags) != 1)

		ksft_print_msg("Error reading %s\n", MAX_SKB_FRAGS_PATH);



	fclose(file);

	return max_skb_frags;

}



static struct option long_options[] = {

	{"interface", required_argument, 0, 'i'},

	{"busy-poll", no_argument, 0, 'b'},
@@ -2244,13 +2263,24 @@ static int testapp_poll_rxq_tmout(struct test_spec *test) 


static int testapp_too_many_frags(struct test_spec *test)

{

	struct pkt pkts[2 * XSK_DESC__MAX_SKB_FRAGS + 2] = {};

	struct pkt *pkts;

	u32 max_frags, i;

	int ret;



	if (test->mode == TEST_MODE_ZC)

	if (test->mode == TEST_MODE_ZC) {

		max_frags = test->ifobj_tx->xdp_zc_max_segs;

	else

		max_frags = XSK_DESC__MAX_SKB_FRAGS;

	} else {

		max_frags = get_max_skb_frags();

		if (!max_frags) {

			ksft_print_msg("Couldn't retrieve MAX_SKB_FRAGS from system, using default (17) value\n");

			max_frags = 17;

		}

		max_frags += 1;

	}



	pkts = calloc(2 * max_frags + 2, sizeof(struct pkt));

	if (!pkts)

		return TEST_FAILURE;



	test->mtu = MAX_ETH_JUMBO_SIZE;
@@ -2280,7 +2310,10 @@ static int testapp_too_many_frags(struct test_spec *test) 
	pkts[2 * max_frags + 1].valid = true;



	pkt_stream_generate_custom(test, pkts, 2 * max_frags + 2);

	return testapp_validate_traffic(test);

	ret = testapp_validate_traffic(test);



	free(pkts);

	return ret;

}



static int xsk_load_xdp_programs(struct ifobject *ifobj)

tools/testing/selftests/bpf/xskxceiver.h

+0 −1
Original line number Diff line number Diff line
@@ -55,7 +55,6 @@ 
#define XSK_UMEM__LARGE_FRAME_SIZE (3 * 1024)

#define XSK_UMEM__MAX_FRAME_SIZE (4 * 1024)

#define XSK_DESC__INVALID_OPTION (0xffff)

#define XSK_DESC__MAX_SKB_FRAGS 18

#define HUGEPAGE_SIZE (2 * 1024 * 1024)

#define PKT_DUMP_NB_TO_PRINT 16

#define RUN_ALL_TESTS UINT_MAX