IB/ipath: Fix calculation for number of kernel PIO buffers

If the module parameter "kpiobufs" is set too high, the calculation to
reset it to a sane value was incorrect.

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 16 insertions, 21 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_init_chip.c b/drivers/infiniband/hw/ipath/ipath_init_chip.c
index d4f6b5239ef8..1e77b55afe93 100644
--- a/drivers/infiniband/hw/ipath/ipath_init_chip.c
+++ b/drivers/infiniband/hw/ipath/ipath_init_chip.c
@@ -668,6 +668,7 @@ int ipath_init_chip(struct ipath_devdata *dd, int reinit)
 {
         int ret = 0, i;
         u32 val32, kpiobufs;
+        u32 piobufs, uports;
         u64 val;
         struct ipath_portdata *pd = NULL; /* keep gcc4 happy */
         gfp_t gfp_flags = GFP_USER | __GFP_COMP;
@@ -702,16 +703,17 @@ int ipath_init_chip(struct ipath_devdata *dd, int reinit)
          * the in memory DMA'ed copies of the registers.  This has to
          * be done early, before we calculate lastport, etc.
          */
-        val = dd->ipath_piobcnt2k + dd->ipath_piobcnt4k;
+        piobufs = dd->ipath_piobcnt2k + dd->ipath_piobcnt4k;
         /*
          * calc number of pioavail registers, and save it; we have 2
          * bits per buffer.
          */
-        dd->ipath_pioavregs = ALIGN(val, sizeof(u64) * BITS_PER_BYTE / 2)
+        dd->ipath_pioavregs = ALIGN(piobufs, sizeof(u64) * BITS_PER_BYTE / 2)
                 / (sizeof(u64) * BITS_PER_BYTE / 2);
+        uports = dd->ipath_cfgports ? dd->ipath_cfgports - 1 : 0;
         if (ipath_kpiobufs == 0) {
                 /* not set by user (this is default) */
-                if ((dd->ipath_piobcnt2k + dd->ipath_piobcnt4k) > 128)
+                if (piobufs >= (uports * IPATH_MIN_USER_PORT_BUFCNT) + 32)
                         kpiobufs = 32;
                 else
                         kpiobufs = 16;
@@ -719,31 +721,25 @@ int ipath_init_chip(struct ipath_devdata *dd, int reinit)
         else
                 kpiobufs = ipath_kpiobufs;
 
-        if (kpiobufs >
-            (dd->ipath_piobcnt2k + dd->ipath_piobcnt4k -
-             (dd->ipath_cfgports * IPATH_MIN_USER_PORT_BUFCNT))) {
-                i = dd->ipath_piobcnt2k + dd->ipath_piobcnt4k -
-                        (dd->ipath_cfgports * IPATH_MIN_USER_PORT_BUFCNT);
+        if (kpiobufs + (uports * IPATH_MIN_USER_PORT_BUFCNT) > piobufs) {
+                i = (int) piobufs -
+                        (int) (uports * IPATH_MIN_USER_PORT_BUFCNT);
                 if (i < 0)
                         i = 0;
-                dev_info(&dd->pcidev->dev, "Allocating %d PIO bufs for "
-                         "kernel leaves too few for %d user ports "
+                dev_info(&dd->pcidev->dev, "Allocating %d PIO bufs of "
+                         "%d for kernel leaves too few for %d user ports "
                          "(%d each); using %u\n", kpiobufs,
-                         dd->ipath_cfgports - 1,
-                         IPATH_MIN_USER_PORT_BUFCNT, i);
+                         piobufs, uports, IPATH_MIN_USER_PORT_BUFCNT, i);
                 /*
                  * shouldn't change ipath_kpiobufs, because could be
                  * different for different devices...
                  */
                 kpiobufs = i;
         }
-        dd->ipath_lastport_piobuf =
-                dd->ipath_piobcnt2k + dd->ipath_piobcnt4k - kpiobufs;
-        dd->ipath_pbufsport = dd->ipath_cfgports > 1
-                ? dd->ipath_lastport_piobuf / (dd->ipath_cfgports - 1)
-                : 0;
-        val32 = dd->ipath_lastport_piobuf -
-                (dd->ipath_pbufsport * (dd->ipath_cfgports - 1));
+        dd->ipath_lastport_piobuf = piobufs - kpiobufs;
+        dd->ipath_pbufsport =
+                uports ? dd->ipath_lastport_piobuf / uports : 0;
+        val32 = dd->ipath_lastport_piobuf - (dd->ipath_pbufsport * uports);
         if (val32 > 0) {
                 ipath_dbg("allocating %u pbufs/port leaves %u unused, "
                           "add to kernel\n", dd->ipath_pbufsport, val32);
@@ -754,8 +750,7 @@ int ipath_init_chip(struct ipath_devdata *dd, int reinit)
         dd->ipath_lastpioindex = dd->ipath_lastport_piobuf;
         ipath_cdbg(VERBOSE, "%d PIO bufs for kernel out of %d total %u "
                    "each for %u user ports\n", kpiobufs,
-                   dd->ipath_piobcnt2k + dd->ipath_piobcnt4k,
-                   dd->ipath_pbufsport, dd->ipath_cfgports - 1);
+                   piobufs, dd->ipath_pbufsport, uports);
 
         dd->ipath_f_early_init(dd);