2 files changed, 118 insertions, 101 deletions

diff --git a/drivers/infiniband/hw/qib/qib_common.h b/drivers/infiniband/hw/qib/qib_common.h
index b3955ed8f794..145da4040883 100644
--- a/drivers/infiniband/hw/qib/qib_common.h
+++ b/drivers/infiniband/hw/qib/qib_common.h
@@ -279,7 +279,7 @@ struct qib_base_info {
  * may not be implemented; the user code must deal with this if it
  * cares, or it must abort after initialization reports the difference.
  */
-#define QIB_USER_SWMINOR 10
+#define QIB_USER_SWMINOR 11
 
 #define QIB_USER_SWVERSION ((QIB_USER_SWMAJOR << 16) | QIB_USER_SWMINOR)
 
@@ -302,6 +302,18 @@ struct qib_base_info {
 #define QIB_KERN_SWVERSION ((QIB_KERN_TYPE << 31) | QIB_USER_SWVERSION)
 
 /*
+ * If the unit is specified via open, HCA choice is fixed.  If port is
+ * specified, it's also fixed.  Otherwise we try to spread contexts
+ * across ports and HCAs, using different algorithims.  WITHIN is
+ * the old default, prior to this mechanism.
+ */
+#define QIB_PORT_ALG_ACROSS 0 /* round robin contexts across HCAs, then
+                               * ports; this is the default */
+#define QIB_PORT_ALG_WITHIN 1 /* use all contexts on an HCA (round robin
+                               * active ports within), then next HCA */
+#define QIB_PORT_ALG_COUNT 2 /* number of algorithm choices */
+
+/*
  * This structure is passed to qib_userinit() to tell the driver where
  * user code buffers are, sizes, etc.   The offsets and sizes of the
  * fields must remain unchanged, for binary compatibility.  It can
@@ -319,7 +331,7 @@ struct qib_user_info {
         /* size of struct base_info to write to */
         __u32 spu_base_info_size;
 
-        __u32 _spu_unused3;
+        __u32 spu_port_alg; /* which QIB_PORT_ALG_*; unused user minor < 11 */
 
         /*
          * If two or more processes wish to share a context, each process
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;
         }