mlx4: Correct error flows in rereg_mr

This patch addresses feedback from Sagi Grimberg on the rereg_mr
implementation of mlx4.  The following are fixed:

1. Set the correct pd_flags
2. Make sure we change the iova and size MR fields only after
   successful write and allocation of the MTTs.
3. Make the error checking more robust

Fixes: e630664c8383 ("mlx4_core: Add helper functions to support MR re-registration")
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/infiniband/hw/mlx4/mr.c b/drivers/infiniband/hw/mlx4/mr.c
index 9b0e80e59b08..8f9325cfc85d 100644
--- a/drivers/infiniband/hw/mlx4/mr.c
+++ b/drivers/infiniband/hw/mlx4/mr.c
@@ -234,14 +234,13 @@ int mlx4_ib_rereg_user_mr(struct ib_mr *mr, int flags,
                                         0);
                 if (IS_ERR(mmr->umem)) {
                         err = PTR_ERR(mmr->umem);
+                        /* Prevent mlx4_ib_dereg_mr from free'ing invalid pointer */
                         mmr->umem = NULL;
                         goto release_mpt_entry;
                 }
                 n = ib_umem_page_count(mmr->umem);
                 shift = ilog2(mmr->umem->page_size);
 
-                mmr->mmr.iova       = virt_addr;
-                mmr->mmr.size       = length;
                 err = mlx4_mr_rereg_mem_write(dev->dev, &mmr->mmr,
                                               virt_addr, length, n, shift,
                                               *pmpt_entry);
@@ -249,6 +248,8 @@ int mlx4_ib_rereg_user_mr(struct ib_mr *mr, int flags,
                         ib_umem_release(mmr->umem);
                         goto release_mpt_entry;
                 }
+                mmr->mmr.iova       = virt_addr;
+                mmr->mmr.size       = length;
 
                 err = mlx4_ib_umem_write_mtt(dev, &mmr->mmr.mtt, mmr->umem);
                 if (err) {
@@ -262,6 +263,8 @@ int mlx4_ib_rereg_user_mr(struct ib_mr *mr, int flags,
          * return a failure. But dereg_mr will free the resources.
          */
         err = mlx4_mr_hw_write_mpt(dev->dev, &mmr->mmr, pmpt_entry);
+        if (!err && flags & IB_MR_REREG_ACCESS)
+                mmr->mmr.access = mr_access_flags;
 
 release_mpt_entry:
         mlx4_mr_hw_put_mpt(dev->dev, pmpt_entry);