From acdd7cbae42d884d82df7dc18601707ca8e20211 Mon Sep 17 00:00:00 2001
From: mav <mav@FreeBSD.org>
Date: Fri, 10 Mar 2017 13:39:16 +0000
Subject: [PATCH] Improve residuals reporting in target mode.

MFC after:	2 weeks
---
 sys/dev/mpt/mpt.h     | 2 +-
 sys/dev/mpt/mpt_cam.c | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/sys/dev/mpt/mpt.h b/sys/dev/mpt/mpt.h
index de7e6a89f9ad..5b9fd8216119 100644
--- a/sys/dev/mpt/mpt.h
+++ b/sys/dev/mpt/mpt.h
@@ -331,8 +331,8 @@ typedef struct mpt_config_params {
 /**************************** MPI Target State Info ***************************/
 typedef struct {
 	uint32_t reply_desc;	/* current reply descriptor */
-	uint32_t resid;		/* current data residual */
 	uint32_t bytes_xfered;	/* current relative offset */
+	int resid;		/* current data residual */
 	union ccb *ccb;		/* pointer to currently active ccb */
 	request_t *req;		/* pointer to currently active assist request */
 	uint32_t
diff --git a/sys/dev/mpt/mpt_cam.c b/sys/dev/mpt/mpt_cam.c
index 19befc2f1f0c..d4cd74ab7c6c 100644
--- a/sys/dev/mpt/mpt_cam.c
+++ b/sys/dev/mpt/mpt_cam.c
@@ -4430,6 +4430,7 @@ mpt_target_start_io(struct mpt_softc *mpt, union ccb *ccb)
 		/*
 		 * XXX Should be done after data transfer completes?
 		 */
+		csio->resid = csio->dxfer_len - ta->DataLength;
 		tgt->resid -= csio->dxfer_len;
 		tgt->bytes_xfered += csio->dxfer_len;
 
@@ -4732,7 +4733,11 @@ mpt_scsi_tgt_status(struct mpt_softc *mpt, union ccb *ccb, request_t *cmd_req,
 #ifndef	WE_TRUST_AUTO_GOOD_STATUS
 		resplen = MIN_FCP_RESPONSE_SIZE;
 #endif
-		if (tgt->resid) {
+		if (tgt->resid < 0) {
+			rsp[2] |= htobe32(0x400); /* XXXX NEED MNEMONIC!!!! */
+			rsp[3] = htobe32(-tgt->resid);
+			resplen = MIN_FCP_RESPONSE_SIZE;
+		} else if (tgt->resid > 0) {
 			rsp[2] |= htobe32(0x800); /* XXXX NEED MNEMONIC!!!! */
 			rsp[3] = htobe32(tgt->resid);
 			resplen = MIN_FCP_RESPONSE_SIZE;