Commit 0158e864 authored by Stefan Metzmacher's avatar Stefan Metzmacher Committed by Steve French
Browse files

smb: server: make use of smbdirect_socket.send_io.lcredits.* 



This introduces logic to prevent on overflow of
the send submission queue with ib_post_send() easier.

As we first get a local credit and then a remote credit
before we mark us as pending.

From reading the git history of the linux smbdirect
implementations in client and server) it was seen
that a peer granted more credits than we requested.
I guess that only happened because of bugs in our
implementation which was active as client and server.
I guess Windows won't do that.

So the local credits make sure we only use the amount
of credits we asked for.

Fixes: 0626e664 ("cifsd: add server handler for central processing and tranport layers")
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: default avatarStefan Metzmacher <metze@samba.org>
Acked-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent a9022746

fs/smb/server/transport_rdma.c

+37 −5
Original line number Diff line number Diff line
@@ -219,6 +219,7 @@ static void smb_direct_disconnect_wake_up_all(struct smbdirect_socket *sc) 
	 * in order to notice the broken connection.

	 */

	wake_up_all(&sc->status_wait);

	wake_up_all(&sc->send_io.lcredits.wait_queue);

	wake_up_all(&sc->send_io.credits.wait_queue);

	wake_up_all(&sc->send_io.pending.zero_wait_queue);

	wake_up_all(&sc->recv_io.reassembly.wait_queue);
@@ -916,6 +917,7 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc) 
{

	struct smbdirect_send_io *sendmsg, *sibling, *next;

	struct smbdirect_socket *sc;

	int lcredits = 0;



	sendmsg = container_of(wc->wr_cqe, struct smbdirect_send_io, cqe);

	sc = sendmsg->socket;
@@ -930,9 +932,11 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc) 
	list_for_each_entry_safe(sibling, next, &sendmsg->sibling_list, sibling_list) {

		list_del_init(&sibling->sibling_list);

		smb_direct_free_sendmsg(sc, sibling);

		lcredits += 1;

	}

	/* Note this frees wc->wr_cqe, but not wc */

	smb_direct_free_sendmsg(sc, sendmsg);

	lcredits += 1;



	if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_SEND) {

		pr_err("Send error. status='%s (%d)', opcode=%d\n",
@@ -942,6 +946,9 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc) 
		return;

	}



	atomic_add(lcredits, &sc->send_io.lcredits.count);

	wake_up(&sc->send_io.lcredits.wait_queue);



	if (atomic_dec_and_test(&sc->send_io.pending.count))

		wake_up(&sc->send_io.pending.zero_wait_queue);

}
@@ -1081,6 +1088,23 @@ static int wait_for_credits(struct smbdirect_socket *sc, 
	} while (true);

}



static int wait_for_send_lcredit(struct smbdirect_socket *sc,

				 struct smbdirect_send_batch *send_ctx)

{

	if (send_ctx && (atomic_read(&sc->send_io.lcredits.count) <= 1)) {

		int ret;



		ret = smb_direct_flush_send_list(sc, send_ctx, false);

		if (ret)

			return ret;

	}



	return wait_for_credits(sc,

				&sc->send_io.lcredits.wait_queue,

				&sc->send_io.lcredits.count,

				1);

}



static int wait_for_send_credits(struct smbdirect_socket *sc,

				 struct smbdirect_send_batch *send_ctx)

{
@@ -1268,9 +1292,13 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc, 
	int data_length;

	struct scatterlist sg[SMBDIRECT_SEND_IO_MAX_SGE - 1];



	ret = wait_for_send_lcredit(sc, send_ctx);

	if (ret)

		goto lcredit_failed;



	ret = wait_for_send_credits(sc, send_ctx);

	if (ret)

		return ret;

		goto credit_failed;



	data_length = 0;

	for (i = 0; i < niov; i++)
@@ -1278,10 +1306,8 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc, 


	ret = smb_direct_create_header(sc, data_length, remaining_data_length,

				       &msg);

	if (ret) {

		atomic_inc(&sc->send_io.credits.count);

		return ret;

	}

	if (ret)

		goto header_failed;



	for (i = 0; i < niov; i++) {

		struct ib_sge *sge;
@@ -1319,7 +1345,11 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc, 
	return 0;

err:

	smb_direct_free_sendmsg(sc, msg);

header_failed:

	atomic_inc(&sc->send_io.credits.count);

credit_failed:

	atomic_inc(&sc->send_io.lcredits.count);

lcredit_failed:

	return ret;

}
@@ -1897,6 +1927,8 @@ static int smb_direct_init_params(struct smbdirect_socket *sc) 
		return -EINVAL;

	}



	atomic_set(&sc->send_io.lcredits.count, sp->send_credit_target);



	maxpages = DIV_ROUND_UP(sp->max_read_write_size, PAGE_SIZE);

	sc->rw_io.credits.max = rdma_rw_mr_factor(sc->ib.dev,

						  sc->rdma.cm_id->port_num,