[PATCH rdma-next 5/6] RDMA/mlx5: Change check for cacheable user mkeys

[Leon Romanovsky <leon@kernel.org>]

From: Or Har-Toov <ohartoov@nvidia.com>

In the dereg flow, UMEM is not a good enough indication whether an MR
is from userspace since in mlx5_ib_rereg_user_mr there are some cases
when a new MR is created and the UMEM of the old MR is set to NULL.
Currently when mlx5_ib_dereg_mr is called on the old MR, UMEM is NULL
but cache_ent can be different than NULL. So, the mkey will not be
destroyed.
Therefore checking if mkey is from user application and cacheable
should be done by checking if rb_key or cache_ent exist and all other kind of
mkeys should be destroyed.

Fixes: dd1b913fb0d0 ("RDMA/mlx5: Cache all user cacheable mkeys on dereg MR flow")
Signed-off-by: Or Har-Toov <ohartoov@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/hw/mlx5/mr.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 12bca6ca4760..3c241898e064 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1857,6 +1857,11 @@ static int cache_ent_find_and_store(struct mlx5_ib_dev *dev,
 	return ret;
 }
 
+static bool is_cacheable_mkey(struct mlx5_ib_mkey mkey)
+{
+	return mkey.cache_ent || mkey.rb_key.ndescs;
+}
+
 int mlx5_ib_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
 {
 	struct mlx5_ib_mr *mr = to_mmr(ibmr);
@@ -1901,12 +1906,6 @@ int mlx5_ib_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
 		mr->sig = NULL;
 	}
 
-	/* Stop DMA */
-	if (mr->umem && mlx5r_umr_can_load_pas(dev, mr->umem->length))
-		if (mlx5r_umr_revoke_mr(mr) ||
-		    cache_ent_find_and_store(dev, mr))
-			mr->mmkey.cache_ent = NULL;
-
 	if (mr->umem && mr->umem->is_peer) {
 		rc = mlx5r_umr_revoke_mr(mr);
 		if (rc)
@@ -1914,7 +1913,9 @@ int mlx5_ib_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
 		ib_umem_stop_invalidation_notifier(mr->umem);
 	}
 
-	if (!mr->mmkey.cache_ent) {
+	/* Stop DMA */
+	if (!is_cacheable_mkey(mr->mmkey) || mlx5r_umr_revoke_mr(mr) ||
+	    cache_ent_find_and_store(dev, mr)) {
 		rc = destroy_mkey(to_mdev(mr->ibmr.device), mr);
 		if (rc)
 			return rc;
-- 
2.43.0