Commit f18ec422 authored Mar 04, 2021 by Jason Gunthorpe

RDMA/mlx5: Use a union inside mlx5_ib_mr

The struct mlx5_ib_mr can be used for three different things, but only one
at a time:

 - In the user MR cache
 - As a kernel MR
 - As a user MR

Overlay the three things into a single union with the following rules:

 - If the mr is found on the cache_ent->head list then it is a cache MR
   and umem == NULL. The entire union is zero after the MR is removed from
   the cache.

 - If umem != NULL or type == IB_MR_TYPE_USER then it is a user MR.

 - If umem == NULL then it is a kernel MR

This reduces the size of struct mlx5_ib_mr to 552 bytes from 702.

The only place the three flows overlap in the code is during dereg, so add
a few extra checks along there.

Link: https://lore.kernel.org/r/20210304120745.1090751-3-leon@kernel.org


Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

parent a639e667

drivers/infiniband/hw/mlx5/mlx5_ib.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -657,7 +657,7 @@ struct mlx5_ib_mr {
		struct ib_umem *umem;

		/* This is zero'd when the MR is allocated */
		struct {
		union {
		/* Used only while the MR is in the cache */
		struct {
		u32 out[MLX5_ST_SZ_DW(create_mkey_out)];

drivers/infiniband/hw/mlx5/mr.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1929,7 +1929,7 @@ mlx5_alloc_priv_descs(struct ib_device *device,
		static void
		mlx5_free_priv_descs(struct mlx5_ib_mr *mr)
		{
		if (mr->descs) {
		if (!mr->umem && mr->descs) {
		struct ib_device *device = mr->ibmr.device;
		int size = mr->max_descs * mr->desc_size;
		struct mlx5_ib_dev *dev = to_mdev(device);
		@@ -1943,7 +1943,7 @@ mlx5_free_priv_descs(struct mlx5_ib_mr *mr)

		static void clean_mr(struct mlx5_ib_dev dev, struct mlx5_ib_mr mr)
		{
		if (mr->sig) {
		if (mr->ibmr.type == IB_MR_TYPE_INTEGRITY) {
		if (mlx5_core_destroy_psv(dev->mdev,
		mr->sig->psv_memory.psv_idx))
		mlx5_ib_warn(dev, "failed to destroy mem psv %d\n",