RDMA/nes: Check for zero STag

STags are generated randomly but the driver does not correctly prevent
a zero STag.  Using STag zero is privileged and causes a user space
application to fail.  This change prevents the driver from trying to
allocate a zero STag.

Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

2 files changed, 2 insertions, 4 deletions

diff --git a/drivers/infiniband/hw/nes/nes_hw.c b/drivers/infiniband/hw/nes/nes_hw.c
index 9fc0273dd409..b1c2cbb88f09 100644
--- a/drivers/infiniband/hw/nes/nes_hw.c
+++ b/drivers/infiniband/hw/nes/nes_hw.c
@@ -437,11 +437,12 @@ struct nes_adapter *nes_init_adapter(struct nes_device *nesdev, u8 hw_rev) {
         nesadapter->qp_table = (struct nes_qp **)(&nesadapter->allocated_arps[BITS_TO_LONGS(arp_table_size)]);
 
 
-        /* mark the usual suspect QPs and CQs as in use */
+        /* mark the usual suspect QPs, MR and CQs as in use */
         for (u32temp = 0; u32temp < NES_FIRST_QPN; u32temp++) {
                 set_bit(u32temp, nesadapter->allocated_qps);
                 set_bit(u32temp, nesadapter->allocated_cqs);
         }
+        set_bit(0, nesadapter->allocated_mrs);
 
         for (u32temp = 0; u32temp < 20; u32temp++)
                 set_bit(u32temp, nesadapter->allocated_pds);
diff --git a/drivers/infiniband/hw/nes/nes_verbs.c b/drivers/infiniband/hw/nes/nes_verbs.c
index 67a87cb9d773..53dc39f43008 100644
--- a/drivers/infiniband/hw/nes/nes_verbs.c
+++ b/drivers/infiniband/hw/nes/nes_verbs.c
@@ -2503,9 +2503,6 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
                         stag = stag_index << 8;
                         stag |= driver_key;
                         stag += (u32)stag_key;
-                        if (stag == 0) {
-                                stag = 1;
-                        }
 
                         iova_start = virt;
                         /* Make the leaf PBL the root if only one PBL */