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Commit e5c93883 authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

libceph: use MSG_TRUNC for discarding received bytes 



Avoid a copy into the "skip buffer".

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent d2935d6f

net/ceph/messenger.c

+8 −13
Original line number Diff line number Diff line
@@ -168,12 +168,6 @@ static char tag_keepalive2 = CEPH_MSGR_TAG_KEEPALIVE2; 
static struct lock_class_key socket_class;

#endif



/*

 * When skipping (ignoring) a block of input we read it into a "skip

 * buffer," which is this many bytes in size.

 */

#define SKIP_BUF_SIZE	1024



static void queue_con(struct ceph_connection *con);

static void cancel_con(struct ceph_connection *con);

static void ceph_con_workfn(struct work_struct *);
@@ -520,12 +514,18 @@ static int ceph_tcp_connect(struct ceph_connection *con) 
	return 0;

}



/*

 * If @buf is NULL, discard up to @len bytes.

 */

static int ceph_tcp_recvmsg(struct socket *sock, void *buf, size_t len)

{

	struct kvec iov = {buf, len};

	struct msghdr msg = { .msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL };

	int r;



	if (!buf)

		msg.msg_flags |= MSG_TRUNC;



	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &iov, 1, len);

	r = sock_recvmsg(sock, &msg, msg.msg_flags);

	if (r == -EAGAIN)
@@ -2717,16 +2717,11 @@ static int try_read(struct ceph_connection *con) 
	if (con->in_base_pos < 0) {

		/*

		 * skipping + discarding content.

		 *

		 * FIXME: there must be a better way to do this!

		 */

		static char buf[SKIP_BUF_SIZE];

		int skip = min((int) sizeof (buf), -con->in_base_pos);



		dout("skipping %d / %d bytes\n", skip, -con->in_base_pos);

		ret = ceph_tcp_recvmsg(con->sock, buf, skip);

		ret = ceph_tcp_recvmsg(con->sock, NULL, -con->in_base_pos);

		if (ret <= 0)

			goto out;

		dout("skipped %d / %d bytes\n", ret, -con->in_base_pos);

		con->in_base_pos += ret;

		if (con->in_base_pos)

			goto more;