RDMA/mlx5: Merge similar flows of allocating MR from the cache

When allocating a MR from the cache, the driver calls to get_cache_mr(),
and in case of failure, retries with create_cache_mr(). This is the flow
of mlx5_mr_cache_alloc(), so use it instead.

Link: https://lore.kernel.org/r/53c85fcd4de6ec9de0b8e6cbb1bf5d5fe19900c3.1644947594.git.leonro@nvidia.com
Signed-off-by: Aharon Landau <aharonl@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/mlx5/mlx5_ib.h

@@ -1343,7 +1343,8 @@ int mlx5_mr_cache_init(struct mlx5_ib_dev *dev);
 int mlx5_mr_cache_cleanup(struct mlx5_ib_dev *dev);
 
 struct mlx5_ib_mr *mlx5_mr_cache_alloc(struct mlx5_ib_dev *dev,
-				       unsigned int entry, int access_flags);
+				       struct mlx5_cache_ent *ent,
+				       int access_flags);
 
 int mlx5_ib_check_mr_status(struct ib_mr *ibmr, u32 check_mask,
 			    struct ib_mr_status *mr_status);

drivers/infiniband/hw/mlx5/mr.c

@@ -558,23 +558,16 @@ static void delayed_cache_work_func(struct work_struct *work)
 	__cache_work_func(ent);
 }
 
-/* Allocate a special entry from the cache */
 struct mlx5_ib_mr *mlx5_mr_cache_alloc(struct mlx5_ib_dev *dev,
-				       unsigned int entry, int access_flags)
+				       struct mlx5_cache_ent *ent,
+				       int access_flags)
 {
-	struct mlx5_mr_cache *cache = &dev->cache;
-	struct mlx5_cache_ent *ent;
 	struct mlx5_ib_mr *mr;
 
-	if (WARN_ON(entry <= MR_CACHE_LAST_STD_ENTRY ||
-		    entry >= ARRAY_SIZE(cache->ent)))
-		return ERR_PTR(-EINVAL);
-
 	/* Matches access in alloc_cache_mr() */
 	if (!mlx5_ib_can_reconfig_with_umr(dev, 0, access_flags))
 		return ERR_PTR(-EOPNOTSUPP);
 
-	ent = &cache->ent[entry];
 	spin_lock_irq(&ent->lock);
 	if (list_empty(&ent->head)) {
 		queue_adjust_cache_locked(ent);
@@ -592,32 +585,9 @@ struct mlx5_ib_mr *mlx5_mr_cache_alloc(struct mlx5_ib_dev *dev,
 
 		mlx5_clear_mr(mr);
 	}
-	mr->access_flags = access_flags;
 	return mr;
 }
 
-/* Return a MR already available in the cache */
-static struct mlx5_ib_mr *get_cache_mr(struct mlx5_cache_ent *req_ent)
-{
-	struct mlx5_ib_mr *mr = NULL;
-	struct mlx5_cache_ent *ent = req_ent;
-
-	spin_lock_irq(&ent->lock);
-	if (!list_empty(&ent->head)) {
-		mr = list_first_entry(&ent->head, struct mlx5_ib_mr, list);
-		list_del(&mr->list);
-		ent->available_mrs--;
-		queue_adjust_cache_locked(ent);
-		spin_unlock_irq(&ent->lock);
-		mlx5_clear_mr(mr);
-		return mr;
-	}
-	queue_adjust_cache_locked(ent);
-	spin_unlock_irq(&ent->lock);
-	req_ent->miss++;
-	return NULL;
-}
-
 static void mlx5_mr_cache_free(struct mlx5_ib_dev *dev, struct mlx5_ib_mr *mr)
 {
 	struct mlx5_cache_ent *ent = mr->cache_ent;
@@ -951,16 +921,9 @@ static struct mlx5_ib_mr *alloc_cacheable_mr(struct ib_pd *pd,
 		return mr;
 	}
 
-	mr = get_cache_mr(ent);
-	if (!mr) {
-		mr = create_cache_mr(ent);
-		/*
-		 * The above already tried to do the same stuff as reg_create(),
-		 * no reason to try it again.
-		 */
-		if (IS_ERR(mr))
-			return mr;
-	}
+	mr = mlx5_mr_cache_alloc(dev, ent, access_flags);
+	if (IS_ERR(mr))
+		return mr;
 
 	mr->ibmr.pd = pd;
 	mr->umem = umem;

drivers/infiniband/hw/mlx5/odp.c

@@ -407,6 +407,7 @@ static void mlx5_ib_page_fault_resume(struct mlx5_ib_dev *dev,
 static struct mlx5_ib_mr *implicit_get_child_mr(struct mlx5_ib_mr *imr,
 						unsigned long idx)
 {
+	struct mlx5_ib_dev *dev = mr_to_mdev(imr);
 	struct ib_umem_odp *odp;
 	struct mlx5_ib_mr *mr;
 	struct mlx5_ib_mr *ret;
@@ -418,13 +419,14 @@ static struct mlx5_ib_mr *implicit_get_child_mr(struct mlx5_ib_mr *imr,
 	if (IS_ERR(odp))
 		return ERR_CAST(odp);
 
-	mr = mlx5_mr_cache_alloc(
-		mr_to_mdev(imr), MLX5_IMR_MTT_CACHE_ENTRY, imr->access_flags);
+	mr = mlx5_mr_cache_alloc(dev, &dev->cache.ent[MLX5_IMR_MTT_CACHE_ENTRY],
+				 imr->access_flags);
 	if (IS_ERR(mr)) {
 		ib_umem_odp_release(odp);
 		return mr;
 	}
 
+	mr->access_flags = imr->access_flags;
 	mr->ibmr.pd = imr->ibmr.pd;
 	mr->ibmr.device = &mr_to_mdev(imr)->ib_dev;
 	mr->umem = &odp->umem;
@@ -493,12 +495,15 @@ struct mlx5_ib_mr *mlx5_ib_alloc_implicit_mr(struct mlx5_ib_pd *pd,
 	if (IS_ERR(umem_odp))
 		return ERR_CAST(umem_odp);
 
-	imr = mlx5_mr_cache_alloc(dev, MLX5_IMR_KSM_CACHE_ENTRY, access_flags);
+	imr = mlx5_mr_cache_alloc(dev,
+				  &dev->cache.ent[MLX5_IMR_KSM_CACHE_ENTRY],
+				  access_flags);
 	if (IS_ERR(imr)) {
 		ib_umem_odp_release(umem_odp);
 		return imr;
 	}
 
+	imr->access_flags = access_flags;
 	imr->ibmr.pd = &pd->ibpd;
 	imr->ibmr.iova = 0;
 	imr->umem = &umem_odp->umem;