svn commit: r261770 - stable/10/sys/dev/iscsi

[Edward Tomasz Napierala]

Author: trasz
Date: Tue Feb 11 11:58:54 2014
New Revision: 261770
URL: http://svnweb.freebsd.org/changeset/base/261770

Log:
  MFC r260083:
  
  Fix extremely slow operation with data digests enabled.  This was caused
  by receive code waiting for data digest even when the data segment was
  empty.  It didn't actually read it, but it waited until those four bytes
  become available in the socket buffer, i.e. until any other PDU (e.g. NOP)
  came in.
  
  Sponsored by:	The FreeBSD Foundation

Modified:
  stable/10/sys/dev/iscsi/icl.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/dev/iscsi/icl.c
==============================================================================
--- stable/10/sys/dev/iscsi/icl.c	Tue Feb 11 11:56:50 2014	(r261769)
+++ stable/10/sys/dev/iscsi/icl.c	Tue Feb 11 11:58:54 2014	(r261770)
@@ -239,7 +239,7 @@ icl_pdu_size(const struct icl_pdu *respo
 	    icl_pdu_padding(response);
 	if (response->ip_conn->ic_header_crc32c)
 		len += ISCSI_HEADER_DIGEST_SIZE;
-	if (response->ip_conn->ic_data_crc32c)
+	if (response->ip_data_len != 0 && response->ip_conn->ic_data_crc32c)
 		len += ISCSI_DATA_DIGEST_SIZE;
 
 	return (len);
@@ -615,7 +615,7 @@ icl_conn_receive_pdu(struct icl_conn *ic
 			break;
 
 		ic->ic_receive_state = ICL_CONN_STATE_DATA_DIGEST;
-		if (ic->ic_data_crc32c == false)
+		if (request->ip_data_len == 0 || ic->ic_data_crc32c == false)
 			ic->ic_receive_len = 0;
 		else
 			ic->ic_receive_len = ISCSI_DATA_DIGEST_SIZE;