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Commit aacb0c2e authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

selftests: net: tcp_mmap must use TCP_ZEROCOPY_RECEIVE 



After prior kernel change, mmap() on TCP socket only reserves VMA.

We have to use getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...)
to perform the transfert of pages from skbs in TCP receive queue into such VMA.

struct tcp_zerocopy_receive {
	__u64 address;		/* in: address of mapping */
	__u32 length;		/* in/out: number of bytes to map/mapped */
	__u32 recv_skip_hint;	/* out: amount of bytes to skip */
};

After a successful getsockopt(...TCP_ZEROCOPY_RECEIVE...), @length contains
number of bytes that were mapped, and @recv_skip_hint contains number of bytes
that should be read using conventional read()/recv()/recvmsg() system calls,
to skip a sequence of bytes that can not be mapped, because not properly page
aligned.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Acked-by: default avatarSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 05255b82

tools/testing/selftests/net/tcp_mmap.c

+38 −28
Original line number Diff line number Diff line
@@ -76,9 +76,10 @@ 
#include <time.h>

#include <sys/time.h>

#include <netinet/in.h>

#include <netinet/tcp.h>

#include <arpa/inet.h>

#include <poll.h>

#include <linux/tcp.h>

#include <assert.h>



#ifndef MSG_ZEROCOPY

#define MSG_ZEROCOPY    0x4000000
@@ -134,11 +135,12 @@ void hash_zone(void *zone, unsigned int length) 
void *child_thread(void *arg)

{

	unsigned long total_mmap = 0, total = 0;

	struct tcp_zerocopy_receive zc;

	unsigned long delta_usec;

	int flags = MAP_SHARED;

	struct timeval t0, t1;

	char *buffer = NULL;

	void *oaddr = NULL;

	void *addr = NULL;

	double throughput;

	struct rusage ru;

	int lu, fd;
@@ -153,41 +155,46 @@ void *child_thread(void *arg) 
		perror("malloc");

		goto error;

	}

	if (zflg) {

		addr = mmap(NULL, chunk_size, PROT_READ, flags, fd, 0);

		if (addr == (void *)-1)

			zflg = 0;

	}

	while (1) {

		struct pollfd pfd = { .fd = fd, .events = POLLIN, };

		int sub;



		poll(&pfd, 1, 10000);

		if (zflg) {

			void *naddr;



			naddr = mmap(oaddr, chunk_size, PROT_READ, flags, fd, 0);

			if (naddr == (void *)-1) {

				if (errno == EAGAIN) {

					/* That is if SO_RCVLOWAT is buggy */

					usleep(1000);

					continue;

				}

				if (errno == EINVAL) {

					flags = MAP_SHARED;

					oaddr = NULL;

					goto fallback;

				}

				if (errno != EIO)

					perror("mmap()");

			socklen_t zc_len = sizeof(zc);

			int res;



			zc.address = (__u64)addr;

			zc.length = chunk_size;

			zc.recv_skip_hint = 0;

			res = getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE,

					 &zc, &zc_len);

			if (res == -1)

				break;



			if (zc.length) {

				assert(zc.length <= chunk_size);

				total_mmap += zc.length;

				if (xflg)

					hash_zone(addr, zc.length);

				total += zc.length;

			}

			total_mmap += chunk_size;

			if (zc.recv_skip_hint) {

				assert(zc.recv_skip_hint <= chunk_size);

				lu = read(fd, buffer, zc.recv_skip_hint);

				if (lu > 0) {

					if (xflg)

				hash_zone(naddr, chunk_size);

			total += chunk_size;

			if (!keepflag) {

				flags |= MAP_FIXED;

				oaddr = naddr;

						hash_zone(buffer, lu);

					total += lu;

				}

			}

			continue;

		}

fallback:

		sub = 0;

		while (sub < chunk_size) {

			lu = read(fd, buffer + sub, chunk_size - sub);
@@ -228,6 +235,8 @@ void *child_thread(void *arg) 
error:

	free(buffer);

	close(fd);

	if (zflg)

		munmap(addr, chunk_size);

	pthread_exit(0);

}
@@ -371,7 +380,8 @@ int main(int argc, char *argv[]) 
		setup_sockaddr(cfg_family, host, &listenaddr);



		if (mss &&

		    setsockopt(fdlisten, SOL_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) {

		    setsockopt(fdlisten, IPPROTO_TCP, TCP_MAXSEG,

			       &mss, sizeof(mss)) == -1) {

			perror("setsockopt TCP_MAXSEG");

			exit(1);

		}
@@ -402,7 +412,7 @@ int main(int argc, char *argv[]) 
	setup_sockaddr(cfg_family, host, &addr);



	if (mss &&

	    setsockopt(fd, SOL_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) {

	    setsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) {

		perror("setsockopt TCP_MAXSEG");

		exit(1);

	}