IB/qib: Allow PSM to select from multiple port assignment algorithms

We used to allow only full specification, or using all contexts within
an HCA before moving to the next HCA.  We now allow an additional
method -- round-robining through HCAs -- and make that the default.

Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 104 insertions, 99 deletions

diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
index a142a9eb5226..6b11645edf35 100644
--- a/drivers/infiniband/hw/qib/qib_file_ops.c
+++ b/drivers/infiniband/hw/qib/qib_file_ops.c
@@ -1294,128 +1294,130 @@ bail:
 	return ret;
 }
 
-static inline int usable(struct qib_pportdata *ppd, int active_only)
+static inline int usable(struct qib_pportdata *ppd)
 {
 	struct qib_devdata *dd = ppd->dd;
-	u32 linkok = active_only ? QIBL_LINKACTIVE :
-		 (QIBL_LINKINIT | QIBL_LINKARMED | QIBL_LINKACTIVE);
 
 	return dd && (dd->flags & QIB_PRESENT) && dd->kregbase && ppd->lid &&
-		(ppd->lflags & linkok);
+		(ppd->lflags & QIBL_LINKACTIVE);
 }
 
-static int find_free_ctxt(int unit, struct file *fp,
-			  const struct qib_user_info *uinfo)
+/*
+ * Select a context on the given device, either using a requested port
+ * or the port based on the context number.
+ */
+static int choose_port_ctxt(struct file *fp, struct qib_devdata *dd, u32 port,
+			    const struct qib_user_info *uinfo)
 {
-	struct qib_devdata *dd = qib_lookup(unit);
 	struct qib_pportdata *ppd = NULL;
-	int ret;
-	u32 ctxt;
+	int ret, ctxt;
 
-	if (!dd || (uinfo->spu_port && uinfo->spu_port > dd->num_pports)) {
-		ret = -ENODEV;
-		goto bail;
-	}
-
-	/*
-	 * If users requests specific port, only try that one port, else
-	 * select "best" port below, based on context.
-	 */
-	if (uinfo->spu_port) {
-		ppd = dd->pport + uinfo->spu_port - 1;
-		if (!usable(ppd, 0)) {
+	if (port) {
+		if (!usable(dd->pport + port - 1)) {
 			ret = -ENETDOWN;
-			goto bail;
-		}
+			goto done;
+		} else
+			ppd = dd->pport + port - 1;
 	}
-
-	for (ctxt = dd->first_user_ctxt; ctxt < dd->cfgctxts; ctxt++) {
-		if (dd->rcd[ctxt])
-			continue;
-		/*
-		 * The setting and clearing of user context rcd[x] protected
-		 * by the qib_mutex
-		 */
-		if (!ppd) {
-			/* choose port based on ctxt, if up, else 1st up */
-			ppd = dd->pport + (ctxt % dd->num_pports);
-			if (!usable(ppd, 0)) {
-				int i;
-				for (i = 0; i < dd->num_pports; i++) {
-					ppd = dd->pport + i;
-					if (usable(ppd, 0))
-						break;
-				}
-				if (i == dd->num_pports) {
-					ret = -ENETDOWN;
-					goto bail;
-				}
-			}
+	for (ctxt = dd->first_user_ctxt; ctxt < dd->cfgctxts && dd->rcd[ctxt];
+	     ctxt++)
+		;
+	if (ctxt == dd->cfgctxts) {
+		ret = -EBUSY;
+		goto done;
+	}
+	if (!ppd) {
+		u32 pidx = ctxt % dd->num_pports;
+		if (usable(dd->pport + pidx))
+			ppd = dd->pport + pidx;
+		else {
+			for (pidx = 0; pidx < dd->num_pports && !ppd;
+			     pidx++)
+				if (usable(dd->pport + pidx))
+					ppd = dd->pport + pidx;
 		}
-		ret = setup_ctxt(ppd, ctxt, fp, uinfo);
-		goto bail;
 	}
-	ret = -EBUSY;
+	ret = ppd ? setup_ctxt(ppd, ctxt, fp, uinfo) : -ENETDOWN;
+done:
+	return ret;
+}
+
+static int find_free_ctxt(int unit, struct file *fp,
+			  const struct qib_user_info *uinfo)
+{
+	struct qib_devdata *dd = qib_lookup(unit);
+	int ret;
+
+	if (!dd || (uinfo->spu_port && uinfo->spu_port > dd->num_pports))
+		ret = -ENODEV;
+	else
+		ret = choose_port_ctxt(fp, dd, uinfo->spu_port, uinfo);
 
-bail:
 	return ret;
 }
 
-static int get_a_ctxt(struct file *fp, const struct qib_user_info *uinfo)
+static int get_a_ctxt(struct file *fp, const struct qib_user_info *uinfo,
+		      unsigned alg)
 {
-	struct qib_pportdata *ppd;
-	int ret = 0, devmax;
-	int npresent, nup;
-	int ndev;
+	struct qib_devdata *udd = NULL;
+	int ret = 0, devmax, npresent, nup, ndev, dusable = 0, i;
 	u32 port = uinfo->spu_port, ctxt;
 
 	devmax = qib_count_units(&npresent, &nup);
+	if (!npresent) {
+		ret = -ENXIO;
+		goto done;
+	}
+	if (nup == 0) {
+		ret = -ENETDOWN;
+		goto done;
+	}
 
-	for (ndev = 0; ndev < devmax; ndev++) {
-		struct qib_devdata *dd = qib_lookup(ndev);
-
-		/* device portion of usable() */
-		if (!(dd && (dd->flags & QIB_PRESENT) && dd->kregbase))
-			continue;
-		for (ctxt = dd->first_user_ctxt; ctxt < dd->cfgctxts; ctxt++) {
-			if (dd->rcd[ctxt])
+	if (alg == QIB_PORT_ALG_ACROSS) {
+		unsigned inuse = ~0U;
+		/* find device (with ACTIVE ports) with fewest ctxts in use */
+		for (ndev = 0; ndev < devmax; ndev++) {
+			struct qib_devdata *dd = qib_lookup(ndev);
+			unsigned cused = 0, cfree = 0;
+			if (!dd)
 				continue;
-			if (port) {
-				if (port > dd->num_pports)
-					continue;
-				ppd = dd->pport + port - 1;
-				if (!usable(ppd, 0))
-					continue;
-			} else {
-				/*
-				 * choose port based on ctxt, if up, else
-				 * first port that's up for multi-port HCA
-				 */
-				ppd = dd->pport + (ctxt % dd->num_pports);
-				if (!usable(ppd, 0)) {
-					int j;
-
-					ppd = NULL;
-					for (j = 0; j < dd->num_pports &&
-						!ppd; j++)
-						if (usable(dd->pport + j, 0))
-							ppd = dd->pport + j;
-					if (!ppd)
-						continue; /* to next unit */
-				}
+			if (port && port <= dd->num_pports &&
+			    usable(dd->pport + port - 1))
+				dusable = 1;
+			else
+				for (i = 0; i < dd->num_pports; i++)
+					if (usable(dd->pport + i))
+						dusable++;
+			if (!dusable)
+				continue;
+			for (ctxt = dd->first_user_ctxt; ctxt < dd->cfgctxts;
+			     ctxt++)
+				if (dd->rcd[ctxt])
+					cused++;
+				else
+					cfree++;
+			if (cfree && cused < inuse) {
+				udd = dd;
+				inuse = cused;
 			}
-			ret = setup_ctxt(ppd, ctxt, fp, uinfo);
+		}
+		if (udd) {
+			ret = choose_port_ctxt(fp, udd, port, uinfo);
 			goto done;
 		}
+	} else {
+		for (ndev = 0; ndev < devmax; ndev++) {
+			struct qib_devdata *dd = qib_lookup(ndev);
+			if (dd) {
+				ret = choose_port_ctxt(fp, dd, port, uinfo);
+				if (!ret)
+					goto done;
+				if (ret == -EBUSY)
+					dusable++;
+			}
+		}
 	}
-
-	if (npresent) {
-		if (nup == 0)
-			ret = -ENETDOWN;
-		else
-			ret = -EBUSY;
-	} else
-		ret = -ENXIO;
+	ret = dusable ? -EBUSY : -ENETDOWN;
 
 done:
 	return ret;
@@ -1481,7 +1483,7 @@ static int qib_assign_ctxt(struct file *fp, const struct qib_user_info *uinfo)
 {
 	int ret;
 	int i_minor;
-	unsigned swmajor, swminor;
+	unsigned swmajor, swminor, alg = QIB_PORT_ALG_ACROSS;
 
 	/* Check to be sure we haven't already initialized this file */
 	if (ctxt_fp(fp)) {
@@ -1498,6 +1500,9 @@ static int qib_assign_ctxt(struct file *fp, const struct qib_user_info *uinfo)
 
 	swminor = uinfo->spu_userversion & 0xffff;
 
+	if (swminor >= 11 && uinfo->spu_port_alg < QIB_PORT_ALG_COUNT)
+		alg = uinfo->spu_port_alg;
+
 	mutex_lock(&qib_mutex);
 
 	if (qib_compatible_subctxts(swmajor, swminor) &&
@@ -1514,7 +1519,7 @@ static int qib_assign_ctxt(struct file *fp, const struct qib_user_info *uinfo)
 	if (i_minor)
 		ret = find_free_ctxt(i_minor - 1, fp, uinfo);
 	else
-		ret = get_a_ctxt(fp, uinfo);
+		ret = get_a_ctxt(fp, uinfo, alg);
 
 done_chk_sdma:
 	if (!ret) {
@@ -1862,7 +1867,7 @@ static int disarm_req_delay(struct qib_ctxtdata *rcd)
 {
 	int ret = 0;
 
-	if (!usable(rcd->ppd, 1)) {
+	if (!usable(rcd->ppd)) {
 		int i;
 		/*
 		 * if link is down, or otherwise not usable, delay
@@ -1881,7 +1886,7 @@ static int disarm_req_delay(struct qib_ctxtdata *rcd)
 				set_bit(_QIB_EVENT_DISARM_BUFS_BIT,
 					&rcd->user_event_mask[i]);
 		}
-		for (i = 0; !usable(rcd->ppd, 1) && i < 300; i++)
+		for (i = 0; !usable(rcd->ppd) && i < 300; i++)
 			msleep(100);
 		ret = -ENETDOWN;
 	}