svn commit: r321415 - in stable/11/sys/dev: mpr mps

[Kenneth D. Merry]

Author: ken
Date: Mon Jul 24 14:42:43 2017
New Revision: 321415
URL: https://svnweb.freebsd.org/changeset/base/321415

Log:
  MFC r321207:
    ------------------------------------------------------------------------
    r321207 | ken | 2017-07-19 09:39:01 -0600 (Wed, 19 Jul 2017) | 14 lines
  
    Fix spurious timeouts on commands sent to mps(4) and mpr(4) controllers.
  
    mps_wait_command() and mpr_wait_command() were using getmicrotime() to
    determine elapsed time when checking for a timeout in polled mode.
    getmicrotime() isn't guaranteed to monotonically increase, and that
    caused spurious timeouts occasionally.
  
    Switch to using getmicrouptime(), which does increase monotonically.
    This fixes the spurious timeouts in my test case.
  
    ------------------------------------------------------------------------
  Reviewed by:	slm, scottl
  Sponsored by:	Spectra Logic

Modified:
  stable/11/sys/dev/mpr/mpr.c
  stable/11/sys/dev/mps/mps.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/dev/mpr/mpr.c
==============================================================================
--- stable/11/sys/dev/mpr/mpr.c	Mon Jul 24 06:49:57 2017	(r321414)
+++ stable/11/sys/dev/mpr/mpr.c	Mon Jul 24 14:42:43 2017	(r321415)
@@ -3286,9 +3286,17 @@ mpr_wait_command(struct mpr_softc *sc, struct mpr_comm
 	if (curthread->td_pflags & TDP_NOSLEEPING)
 #endif //__FreeBSD_version >= 1000029
 		sleep_flag = NO_SLEEP;
-	getmicrotime(&start_time);
+	getmicrouptime(&start_time);
 	if (mtx_owned(&sc->mpr_mtx) && sleep_flag == CAN_SLEEP) {
 		error = msleep(cm, &sc->mpr_mtx, 0, "mprwait", timeout*hz);
+		if (error == EWOULDBLOCK) {
+			/*
+			 * Record the actual elapsed time in the case of a
+			 * timeout for the message below.
+			 */
+			getmicrouptime(&cur_time);
+			timevalsub(&cur_time, &start_time);
+		}
 	} else {
 		while ((cm->cm_flags & MPR_CM_FLAGS_COMPLETE) == 0) {
 			mpr_intr_locked(sc);
@@ -3297,8 +3305,9 @@ mpr_wait_command(struct mpr_softc *sc, struct mpr_comm
 			else
 				DELAY(50000);
 		
-			getmicrotime(&cur_time);
-			if ((cur_time.tv_sec - start_time.tv_sec) > timeout) {
+			getmicrouptime(&cur_time);
+			timevalsub(&cur_time, &start_time);
+			if (cur_time.tv_sec > timeout) {
 				error = EWOULDBLOCK;
 				break;
 			}
@@ -3306,7 +3315,9 @@ mpr_wait_command(struct mpr_softc *sc, struct mpr_comm
 	}
 
 	if (error == EWOULDBLOCK) {
-		mpr_dprint(sc, MPR_FAULT, "Calling Reinit from %s\n", __func__);
+		mpr_dprint(sc, MPR_FAULT, "Calling Reinit from %s, timeout=%d,"
+		    " elapsed=%jd\n", __func__, timeout,
+		    (intmax_t)cur_time.tv_sec);
 		rc = mpr_reinit(sc);
 		mpr_dprint(sc, MPR_FAULT, "Reinit %s\n", (rc == 0) ? "success" :
 		    "failed");

Modified: stable/11/sys/dev/mps/mps.c
==============================================================================
--- stable/11/sys/dev/mps/mps.c	Mon Jul 24 06:49:57 2017	(r321414)
+++ stable/11/sys/dev/mps/mps.c	Mon Jul 24 14:42:43 2017	(r321415)
@@ -2551,10 +2551,18 @@ mps_wait_command(struct mps_softc *sc, struct mps_comm
 	 */
 	if (curthread->td_no_sleeping != 0)
 		sleep_flag = NO_SLEEP;
-	getmicrotime(&start_time);
+	getmicrouptime(&start_time);
 	if (mtx_owned(&sc->mps_mtx) && sleep_flag == CAN_SLEEP) {
 		cm->cm_flags |= MPS_CM_FLAGS_WAKEUP;
 		error = msleep(cm, &sc->mps_mtx, 0, "mpswait", timeout*hz);
+		if (error == EWOULDBLOCK) {
+			/*
+			 * Record the actual elapsed time in the case of a
+			 * timeout for the message below.
+			 */
+			getmicrouptime(&cur_time);
+			timevalsub(&cur_time, &start_time);
+		}
 	} else {
 		while ((cm->cm_flags & MPS_CM_FLAGS_COMPLETE) == 0) {
 			mps_intr_locked(sc);
@@ -2563,8 +2571,9 @@ mps_wait_command(struct mps_softc *sc, struct mps_comm
 			else
 				DELAY(50000);
 		
-			getmicrotime(&cur_time);
-			if ((cur_time.tv_sec - start_time.tv_sec) > timeout) {
+			getmicrouptime(&cur_time);
+			timevalsub(&cur_time, &start_time);
+			if (cur_time.tv_sec > timeout) {
 				error = EWOULDBLOCK;
 				break;
 			}
@@ -2572,7 +2581,9 @@ mps_wait_command(struct mps_softc *sc, struct mps_comm
 	}
 
 	if (error == EWOULDBLOCK) {
-		mps_dprint(sc, MPS_FAULT, "Calling Reinit from %s\n", __func__);
+		mps_dprint(sc, MPS_FAULT, "Calling Reinit from %s, timeout=%d,"
+		    " elapsed=%jd\n", __func__, timeout,
+		    (intmax_t)cur_time.tv_sec);
 		rc = mps_reinit(sc);
 		mps_dprint(sc, MPS_FAULT, "Reinit %s\n", (rc == 0) ? "success" :
 		    "failed");