From 49826b36cf919dc4289b6dc801ac758983aa3841 Mon Sep 17 00:00:00 2001
From: Ben Walker <benjamin.walker@intel.com>
Date: Wed, 1 Apr 2020 11:35:23 -0700
Subject: [PATCH] iscsi: Properly size the receive buffer

Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Change-Id: Id736c8a6d9a2cb8bd23017f61eeeccca8a882c03
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/1636
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
---
 lib/iscsi/iscsi.c                      | 23 +++++++++++++++++++++++
 test/unit/lib/iscsi/iscsi.c/iscsi_ut.c |  2 ++
 2 files changed, 25 insertions(+)

diff --git a/lib/iscsi/iscsi.c b/lib/iscsi/iscsi.c
index 85327f083..b0533992c 100644
--- a/lib/iscsi/iscsi.c
+++ b/lib/iscsi/iscsi.c
@@ -40,6 +40,7 @@
 #include "spdk/env.h"
 #include "spdk/likely.h"
 #include "spdk/trace.h"
+#include "spdk/sock.h"
 #include "spdk/string.h"
 #include "spdk/queue.h"
 #include "spdk/net.h"
@@ -1100,6 +1101,7 @@ static int
 iscsi_conn_params_update(struct spdk_iscsi_conn *conn)
 {
 	int rc;
+	uint32_t recv_buf_size;
 
 	/* update internal variables */
 	rc = spdk_iscsi_copy_param2var(conn);
@@ -1120,6 +1122,27 @@ iscsi_conn_params_update(struct spdk_iscsi_conn *conn)
 		}
 	}
 
+	/* The socket receive buffer may need to be adjusted based on the new parameters */
+
+	/* Don't allow the recv buffer to be 0 or very large. */
+	recv_buf_size = spdk_max(0x1000, spdk_min(0x2000, conn->sess->FirstBurstLength));
+
+	/* Add in extra space for the PDU */
+	recv_buf_size += ISCSI_BHS_LEN + ISCSI_AHS_LEN;
+
+	if (conn->header_digest) {
+		recv_buf_size += ISCSI_DIGEST_LEN;
+	}
+
+	if (conn->data_digest) {
+		recv_buf_size += ISCSI_DIGEST_LEN;
+	}
+
+	/* Set up to buffer up to 4 commands with immediate data at once */
+	if (spdk_sock_set_recvbuf(conn->sock, recv_buf_size * 4) < 0) {
+		/* Not fatal. */
+	}
+
 	return rc;
 }
 
diff --git a/test/unit/lib/iscsi/iscsi.c/iscsi_ut.c b/test/unit/lib/iscsi/iscsi.c/iscsi_ut.c
index d0c6005af..030a0c480 100644
--- a/test/unit/lib/iscsi/iscsi.c/iscsi_ut.c
+++ b/test/unit/lib/iscsi/iscsi.c/iscsi_ut.c
@@ -108,6 +108,8 @@ DEFINE_STUB(spdk_iscsi_chap_get_authinfo, int,
 	    (struct iscsi_chap_auth *auth, const char *authuser, int ag_tag),
 	    0);
 
+DEFINE_STUB(spdk_sock_set_recvbuf, int, (struct spdk_sock *sock, int sz), 0);
+
 int
 spdk_scsi_lun_get_id(const struct spdk_scsi_lun *lun)
 {