RDMA/mlx5: Lift implicit_mr_alloc() into the two routines that call it

This makes the routines easier to understand, particularly with respect
the locking requirements of the entire sequence. The implicit_mr_alloc()
had a lot of ifs specializing it to each of the callers, and only a very
small amount of code was actually shared.

Following patches will cause the flow in the two functions to diverge
further.

Link: https://lore.kernel.org/r/20191009160934.3143-7-jgg@ziepe.caReviewed-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/odp.c

@@ -416,96 +416,66 @@ static void mlx5_ib_page_fault_resume(struct mlx5_ib_dev *dev,
 			    wq_num, err);
 }
 
-static struct mlx5_ib_mr *implicit_mr_alloc(struct ib_pd *pd,
-					    struct ib_umem_odp *umem_odp,
-					    bool ksm, int access_flags)
+static struct mlx5_ib_mr *implicit_get_child_mr(struct mlx5_ib_mr *imr,
+						unsigned long idx)
 {
-	struct mlx5_ib_dev *dev = to_mdev(pd->device);
+	struct ib_umem_odp *odp;
 	struct mlx5_ib_mr *mr;
+	struct mlx5_ib_mr *ret;
 	int err;
 
-	mr = mlx5_mr_cache_alloc(dev, ksm ? MLX5_IMR_KSM_CACHE_ENTRY :
-					    MLX5_IMR_MTT_CACHE_ENTRY);
+	odp = ib_umem_odp_alloc_child(to_ib_umem_odp(imr->umem),
+				      idx * MLX5_IMR_MTT_SIZE,
+				      MLX5_IMR_MTT_SIZE);
+	if (IS_ERR(odp))
+		return ERR_CAST(odp);
 
+	ret = mr = mlx5_mr_cache_alloc(imr->dev, MLX5_IMR_MTT_CACHE_ENTRY);
 	if (IS_ERR(mr))
-		return mr;
+		goto out_umem;
 
-	err = xa_reserve(&dev->odp_mkeys, mlx5_base_mkey(mr->mmkey.key),
+	err = xa_reserve(&imr->dev->odp_mkeys, mlx5_base_mkey(mr->mmkey.key),
 			 GFP_KERNEL);
-	if (err)
+	if (err) {
+		ret = ERR_PTR(err);
 		goto out_mr;
+	}
 
-	mr->ibmr.pd = pd;
-
-	mr->dev = dev;
-	mr->access_flags = access_flags;
+	mr->ibmr.pd = imr->ibmr.pd;
+	mr->access_flags = imr->access_flags;
+	mr->umem = &odp->umem;
+	mr->ibmr.lkey = mr->mmkey.key;
+	mr->ibmr.rkey = mr->mmkey.key;
 	mr->mmkey.iova = 0;
-	mr->umem = &umem_odp->umem;
-
-	if (ksm) {
-		err = mlx5_ib_update_xlt(mr, 0,
-					 mlx5_imr_ksm_entries,
-					 MLX5_KSM_PAGE_SHIFT,
-					 MLX5_IB_UPD_XLT_INDIRECT |
-					 MLX5_IB_UPD_XLT_ZAP |
-					 MLX5_IB_UPD_XLT_ENABLE);
+	mr->parent = imr;
+	odp->private = mr;
+	INIT_WORK(&odp->work, mr_leaf_free_action);
 
-	} else {
 	err = mlx5_ib_update_xlt(mr, 0,
 				 MLX5_IMR_MTT_ENTRIES,
 				 PAGE_SHIFT,
 				 MLX5_IB_UPD_XLT_ZAP |
 				 MLX5_IB_UPD_XLT_ENABLE |
 				 MLX5_IB_UPD_XLT_ATOMIC);
-	}
-
-	if (err)
+	if (err) {
+		ret = ERR_PTR(err);
 		goto out_release;
+	}
 
-	mr->ibmr.lkey = mr->mmkey.key;
-	mr->ibmr.rkey = mr->mmkey.key;
-
-	mlx5_ib_dbg(dev, "key %x dev %p mr %p\n",
-		    mr->mmkey.key, dev->mdev, mr);
+	mr->mmkey.iova = idx * MLX5_IMR_MTT_SIZE;
+	xa_store(&imr->dev->odp_mkeys, mlx5_base_mkey(mr->mmkey.key),
+		 &mr->mmkey, GFP_ATOMIC);
 
+	mlx5_ib_dbg(imr->dev, "key %x mr %p\n", mr->mmkey.key, mr);
 	return mr;
 
 out_release:
-	xa_release(&dev->odp_mkeys, mlx5_base_mkey(mr->mmkey.key));
+	xa_release(&imr->dev->odp_mkeys, mlx5_base_mkey(mr->mmkey.key));
 out_mr:
-	mlx5_ib_err(dev, "Failed to register MKEY %d\n", err);
-	mlx5_mr_cache_free(dev, mr);
-
-	return ERR_PTR(err);
-}
-
-static struct mlx5_ib_mr *implicit_get_child_mr(struct mlx5_ib_mr *imr,
-						unsigned long idx)
-{
-	struct ib_umem_odp *odp;
-	struct mlx5_ib_mr *mtt;
-
-	odp = ib_umem_odp_alloc_child(to_ib_umem_odp(imr->umem),
-				      idx * MLX5_IMR_MTT_SIZE,
-				      MLX5_IMR_MTT_SIZE);
-	if (IS_ERR(odp))
-		return ERR_CAST(odp);
-
-	mtt = implicit_mr_alloc(imr->ibmr.pd, odp, 0, imr->access_flags);
-	if (IS_ERR(mtt)) {
+	mlx5_mr_cache_free(imr->dev, mr);
+out_umem:
 	ib_umem_odp_release(odp);
-		return mtt;
-	}
-
-	odp->private = mtt;
-	mtt->umem = &odp->umem;
-	mtt->mmkey.iova = idx * MLX5_IMR_MTT_SIZE;
-	mtt->parent = imr;
-	INIT_WORK(&odp->work, mr_leaf_free_action);
-
-	xa_store(&mtt->dev->odp_mkeys, mlx5_base_mkey(mtt->mmkey.key),
-		 &mtt->mmkey, GFP_ATOMIC);
-	return mtt;
+	return ret;
 }
 
 static struct ib_umem_odp *implicit_mr_get_data(struct mlx5_ib_mr *imr,
@@ -573,27 +543,54 @@ struct mlx5_ib_mr *mlx5_ib_alloc_implicit_mr(struct mlx5_ib_pd *pd,
 					     struct ib_udata *udata,
 					     int access_flags)
 {
-	struct mlx5_ib_mr *imr;
+	struct mlx5_ib_dev *dev = to_mdev(pd->ibpd.device);
 	struct ib_umem_odp *umem_odp;
+	struct mlx5_ib_mr *imr;
+	int err;
 
 	umem_odp = ib_umem_odp_alloc_implicit(udata, access_flags);
 	if (IS_ERR(umem_odp))
 		return ERR_CAST(umem_odp);
 
-	imr = implicit_mr_alloc(&pd->ibpd, umem_odp, 1, access_flags);
+	imr = mlx5_mr_cache_alloc(dev, MLX5_IMR_KSM_CACHE_ENTRY);
 	if (IS_ERR(imr)) {
-		ib_umem_odp_release(umem_odp);
-		return ERR_CAST(imr);
+		err = PTR_ERR(imr);
+		goto out_umem;
 	}
 
+	imr->ibmr.pd = &pd->ibpd;
+	imr->access_flags = access_flags;
+	imr->mmkey.iova = 0;
+	imr->umem = &umem_odp->umem;
+	imr->ibmr.lkey = imr->mmkey.key;
+	imr->ibmr.rkey = imr->mmkey.key;
 	imr->umem = &umem_odp->umem;
 	init_waitqueue_head(&imr->q_leaf_free);
 	atomic_set(&imr->num_leaf_free, 0);
 	atomic_set(&imr->num_pending_prefetch, 0);
-	xa_store(&imr->dev->odp_mkeys, mlx5_base_mkey(imr->mmkey.key),
-		 &imr->mmkey, GFP_ATOMIC);
 
+	err = mlx5_ib_update_xlt(imr, 0,
+				 mlx5_imr_ksm_entries,
+				 MLX5_KSM_PAGE_SHIFT,
+				 MLX5_IB_UPD_XLT_INDIRECT |
+				 MLX5_IB_UPD_XLT_ZAP |
+				 MLX5_IB_UPD_XLT_ENABLE);
+	if (err)
+		goto out_mr;
+
+	err = xa_err(xa_store(&dev->odp_mkeys, mlx5_base_mkey(imr->mmkey.key),
+			      &imr->mmkey, GFP_KERNEL));
+	if (err)
+		goto out_mr;
+
+	mlx5_ib_dbg(dev, "key %x mr %p\n", imr->mmkey.key, imr);
 	return imr;
+out_mr:
+	mlx5_ib_err(dev, "Failed to register MKEY %d\n", err);
+	mlx5_mr_cache_free(dev, imr);
+out_umem:
+	ib_umem_odp_release(umem_odp);
+	return ERR_PTR(err);
 }
 
 void mlx5_ib_free_implicit_mr(struct mlx5_ib_mr *imr)