1 files changed, 19 insertions, 15 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_file_ops.c b/drivers/infiniband/hw/ipath/ipath_file_ops.c
index 1b232b23dbfc..17d4e970abd9 100644
--- a/drivers/infiniband/hw/ipath/ipath_file_ops.c
+++ b/drivers/infiniband/hw/ipath/ipath_file_ops.c
@@ -1930,22 +1930,25 @@ static int ipath_do_user_init(struct file *fp,
         pd->port_hdrqfull_poll = pd->port_hdrqfull;
 
         /*
-         * now enable the port; the tail registers will be written to memory
-         * by the chip as soon as it sees the write to
-         * dd->ipath_kregs->kr_rcvctrl.  The update only happens on
-         * transition from 0 to 1, so clear it first, then set it as part of
-         * enabling the port.  This will (very briefly) affect any other
-         * open ports, but it shouldn't be long enough to be an issue.
-         * We explictly set the in-memory copy to 0 beforehand, so we don't
-         * have to wait to be sure the DMA update has happened.
+         * Now enable the port for receive.
+         * For chips that are set to DMA the tail register to memory
+         * when they change (and when the update bit transitions from
+         * 0 to 1.  So for those chips, we turn it off and then back on.
+         * This will (very briefly) affect any other open ports, but the
+         * duration is very short, and therefore isn't an issue.  We
+         * explictly set the in-memory tail copy to 0 beforehand, so we
+         * don't have to wait to be sure the DMA update has happened
+         * (chip resets head/tail to 0 on transition to enable).
          */
-        if (pd->port_rcvhdrtail_kvaddr)
-                ipath_clear_rcvhdrtail(pd);
         set_bit(dd->ipath_r_portenable_shift + pd->port_port,
                 &dd->ipath_rcvctrl);
-        ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl,
+        if (!(dd->ipath_flags & IPATH_NODMA_RTAIL)) {
+                if (pd->port_rcvhdrtail_kvaddr)
+                        ipath_clear_rcvhdrtail(pd);
+                ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl,
                         dd->ipath_rcvctrl &
                         ~(1ULL << dd->ipath_r_tailupd_shift));
+        }
         ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl,
                          dd->ipath_rcvctrl);
         /* Notify any waiting slaves */
@@ -1973,14 +1976,15 @@ static void unlock_expected_tids(struct ipath_portdata *pd)
         ipath_cdbg(VERBOSE, "Port %u unlocking any locked expTID pages\n",
                    pd->port_port);
         for (i = port_tidbase; i < maxtid; i++) {
-                if (!dd->ipath_pageshadow[i])
+                struct page *ps = dd->ipath_pageshadow[i];
+
+                if (!ps)
                         continue;
 
+                dd->ipath_pageshadow[i] = NULL;
                 pci_unmap_page(dd->pcidev, dd->ipath_physshadow[i],
                         PAGE_SIZE, PCI_DMA_FROMDEVICE);
-                ipath_release_user_pages_on_close(&dd->ipath_pageshadow[i],
-                                                  1);
-                dd->ipath_pageshadow[i] = NULL;
+                ipath_release_user_pages_on_close(&ps, 1);
                 cnt++;
                 ipath_stats.sps_pageunlocks++;
         }