On Tue, 26 May 2026 07:43:56 -0700 Zhiping Zhang <[email protected]> wrote:
> Query dma-buf TPH metadata when registering a dma-buf MR for peer-to- > peer access and translate the returned steering tag into an mlx5 ST > index. Keep the DMAH path as the first priority and only fall back to > DMA-buf metadata when no DMAH is supplied. > > Track per-MR ownership of the allocated ST index and release it on MR > setup failure, destroy, and FRMR-pool reuse. Release the ST index before > the MR is pushed back into the FRMR pool, and free mlx5_st_idx_data when > its refcount reaches zero so repeated allocation/deallocation does not > leak memory. > > Signed-off-by: Zhiping Zhang <[email protected]> > --- > drivers/infiniband/hw/mlx5/mlx5_ib.h | 6 ++ > drivers/infiniband/hw/mlx5/mr.c | 86 ++++++++++++++++++- > .../net/ethernet/mellanox/mlx5/core/lib/st.c | 28 ++++-- > include/linux/mlx5/driver.h | 7 ++ > 4 files changed, 115 insertions(+), 12 deletions(-) > > diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h > b/drivers/infiniband/hw/mlx5/mlx5_ib.h > index e156dc4d7529..4ab867392267 100644 > --- a/drivers/infiniband/hw/mlx5/mlx5_ib.h > +++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h > @@ -721,6 +721,12 @@ struct mlx5_ib_mr { > u8 revoked :1; > /* Indicates previous dmabuf page fault occurred */ > u8 dmabuf_faulted:1; > + /* Set when the MR owns dmabuf_st_index and must > + * release it via mlx5_st_dealloc_index() once the > + * firmware mkey is no longer referencing it. > + */ > + u8 dmabuf_st_owned:1; > + u16 dmabuf_st_index; > struct mlx5_ib_mkey null_mmkey; > }; > }; > diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c > index 3b6da45061a5..8059b5e4da97 100644 > --- a/drivers/infiniband/hw/mlx5/mr.c > +++ b/drivers/infiniband/hw/mlx5/mr.c > @@ -38,6 +38,7 @@ > #include <linux/delay.h> > #include <linux/dma-buf.h> > #include <linux/dma-resv.h> > +#include <linux/pci-tph.h> > #include <rdma/frmr_pools.h> > #include <rdma/ib_umem_odp.h> > #include "dm.h" > @@ -46,6 +47,8 @@ > #include "data_direct.h" > #include "dmah.h" > > +MODULE_IMPORT_NS("DMA_BUF"); > + This doesn't appear to add any dma-buf namespace dependencies. > static int mkey_max_umr_order(struct mlx5_ib_dev *dev) > { > if (MLX5_CAP_GEN(dev->mdev, umr_extended_translation_offset)) > @@ -899,6 +902,63 @@ static struct dma_buf_attach_ops > mlx5_ib_dmabuf_attach_ops = { > .invalidate_mappings = mlx5_ib_dmabuf_invalidate_cb, > }; > > +/* > + * Query TPH metadata from @dmabuf and translate the raw steering tag into > + * an mlx5 ST index. On success, returns 0 and the caller becomes the > + * owner of *@st_index (must be released with mlx5_st_dealloc_index() > + * once the firmware mkey no longer references it). On any failure > + * *@st_index and *@ph are left as the no-TPH defaults set by the caller. > + * > + * @dmabuf must already be referenced by the caller (e.g. via the umem's > + * attachment) so we don't re-resolve the user's fd here and avoid a > + * dup2() TOCTOU between umem creation and TPH lookup. > + */ > +static void get_tph_mr_dmabuf(struct mlx5_ib_dev *dev, struct dma_buf > *dmabuf, > + u16 *st_index, u8 *ph) > +{ > + u8 req_type; > + u16 steering_tag; > + u8 st_width; > + int ret; > + > + if (!dmabuf->ops->get_tph) > + return; > + > + req_type = pcie_tph_enabled_req_type(dev->mdev->pdev); > + switch (req_type) { > + case PCI_TPH_REQ_TPH_ONLY: > + st_width = 8; > + break; > + case PCI_TPH_REQ_EXT_TPH: > + st_width = 16; > + break; > + default: > + return; > + } > + > + ret = dmabuf->ops->get_tph(dmabuf, &steering_tag, ph, st_width); > + if (ret) { > + mlx5_ib_dbg(dev, "get_tph failed (%d)\n", ret); > + *ph = MLX5_IB_NO_PH; > + return; > + } > + > + ret = mlx5_st_alloc_index_by_tag(dev->mdev, steering_tag, st_index); > + if (ret) { > + *ph = MLX5_IB_NO_PH; > + mlx5_ib_dbg(dev, "st_alloc_index_by_tag failed (%d)\n", ret); > + } > +} ph handling is inconsistent, why not use a local variable and only set the caller's pointer on success? > + > +static void mlx5_ib_mr_put_dmabuf_st(struct mlx5_ib_mr *mr) > +{ > + if (mr->umem && mr->dmabuf_st_owned) { > + mlx5_st_dealloc_index(mr_to_mdev(mr)->mdev, > + mr->dmabuf_st_index); > + mr->dmabuf_st_owned = 0; > + } > +} > + > static struct ib_mr * > reg_user_mr_dmabuf(struct ib_pd *pd, struct device *dma_device, > u64 offset, u64 length, u64 virt_addr, > @@ -941,16 +1001,26 @@ reg_user_mr_dmabuf(struct ib_pd *pd, struct device > *dma_device, > ph = dmah->ph; > if (dmah->valid_fields & BIT(IB_DMAH_CPU_ID_EXISTS)) > st_index = mdmah->st_index; > + } else { > + get_tph_mr_dmabuf(dev, umem_dmabuf->attach->dmabuf, > + &st_index, &ph); > } > > mr = alloc_cacheable_mr(pd, &umem_dmabuf->umem, virt_addr, > access_flags, access_mode, > st_index, ph); > if (IS_ERR(mr)) { > + if (!dmah && st_index != > MLX5_MKC_PCIE_TPH_NO_STEERING_TAG_INDEX) > + mlx5_st_dealloc_index(dev->mdev, st_index); > ib_umem_release(&umem_dmabuf->umem); > return ERR_CAST(mr); > } > > + if (!dmah && st_index != MLX5_MKC_PCIE_TPH_NO_STEERING_TAG_INDEX) { > + mr->dmabuf_st_index = st_index; > + mr->dmabuf_st_owned = 1; > + } > + > mlx5_ib_dbg(dev, "mkey 0x%x\n", mr->mmkey.key); > > atomic_add(ib_umem_num_pages(mr->umem), &dev->mdev->priv.reg_pages); > @@ -1377,9 +1447,17 @@ static int mlx5r_handle_mkey_cleanup(struct mlx5_ib_mr > *mr) > bool is_odp = is_odp_mr(mr); > int ret; > > - if (mr->ibmr.frmr.pool && !mlx5_umr_revoke_mr_with_lock(mr) && > - !ib_frmr_pool_push(mr->ibmr.device, &mr->ibmr)) > - return 0; > + if (mr->ibmr.frmr.pool && !mlx5_umr_revoke_mr_with_lock(mr)) { > + /* > + * The mkey has been revoked: firmware no longer references > + * dmabuf_st_index, so release it before this mr can re-enter > + * the FRMR cache for reuse by another registration. > + */ > + mlx5_ib_mr_put_dmabuf_st(mr); > + > + if (!ib_frmr_pool_push(mr->ibmr.device, &mr->ibmr)) > + return 0; > + } > > if (is_odp) > mutex_lock(&to_ib_umem_odp(mr->umem)->umem_mutex); > @@ -1400,6 +1478,8 @@ static int mlx5r_handle_mkey_cleanup(struct mlx5_ib_mr > *mr) > dma_resv_unlock( > to_ib_umem_dmabuf(mr->umem)->attach->dmabuf->resv); > } > + if (!ret) > + mlx5_ib_mr_put_dmabuf_st(mr); > return ret; > } > > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/st.c > b/drivers/net/ethernet/mellanox/mlx5/core/lib/st.c > index 997be91f0a13..8929c17c88bc 100644 > --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/st.c > +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/st.c > @@ -29,7 +29,7 @@ struct mlx5_st *mlx5_st_create(struct mlx5_core_dev *dev) > u8 direct_mode = 0; > u16 num_entries; > u32 tbl_loc; > - int ret; > + int ret = 0; Unnecessary change. > > if (!MLX5_CAP_GEN(dev, mkey_pcie_tph)) > return NULL; > @@ -92,23 +92,18 @@ void mlx5_st_destroy(struct mlx5_core_dev *dev) > kfree(st); > } > > -int mlx5_st_alloc_index(struct mlx5_core_dev *dev, enum tph_mem_type > mem_type, > - unsigned int cpu_uid, u16 *st_index) > +int mlx5_st_alloc_index_by_tag(struct mlx5_core_dev *dev, u16 tag, > + u16 *st_index) > { > struct mlx5_st_idx_data *idx_data; > struct mlx5_st *st = dev->st; > unsigned long index; > u32 xa_id; > - u16 tag; > - int ret; > + int ret = 0; > > if (!st) > return -EOPNOTSUPP; > > - ret = pcie_tph_get_cpu_st(dev->pdev, mem_type, cpu_uid, &tag); > - if (ret) > - return ret; > - > if (st->direct_mode) { > *st_index = tag; > return 0; > @@ -152,6 +147,20 @@ int mlx5_st_alloc_index(struct mlx5_core_dev *dev, enum > tph_mem_type mem_type, > mutex_unlock(&st->lock); > return ret; > } > +EXPORT_SYMBOL_GPL(mlx5_st_alloc_index_by_tag); > + > +int mlx5_st_alloc_index(struct mlx5_core_dev *dev, enum tph_mem_type > mem_type, > + unsigned int cpu_uid, u16 *st_index) > +{ > + u16 tag; > + int ret; > + > + ret = pcie_tph_get_cpu_st(dev->pdev, mem_type, cpu_uid, &tag); > + if (ret) > + return ret; > + > + return mlx5_st_alloc_index_by_tag(dev, tag, st_index); > +} > EXPORT_SYMBOL_GPL(mlx5_st_alloc_index); > > int mlx5_st_dealloc_index(struct mlx5_core_dev *dev, u16 st_index) > @@ -175,6 +184,7 @@ int mlx5_st_dealloc_index(struct mlx5_core_dev *dev, u16 > st_index) > > if (refcount_dec_and_test(&idx_data->usecount)) { > xa_erase(&st->idx_xa, st_index); > + kfree(idx_data); > /* We leave PCI config space as was before, no mkey will refer > to it */ > } Should this be pulled out as a fix separate from the feature added here? Thanks, Alex > > diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h > index 04b96c5abb57..523a9ab0ae1e 100644 > --- a/include/linux/mlx5/driver.h > +++ b/include/linux/mlx5/driver.h > @@ -1166,10 +1166,17 @@ int mlx5_dm_sw_icm_dealloc(struct mlx5_core_dev *dev, > enum mlx5_sw_icm_type type > u64 length, u16 uid, phys_addr_t addr, u32 obj_id); > > #ifdef CONFIG_PCIE_TPH > +int mlx5_st_alloc_index_by_tag(struct mlx5_core_dev *dev, u16 tag, > + u16 *st_index); > int mlx5_st_alloc_index(struct mlx5_core_dev *dev, enum tph_mem_type > mem_type, > unsigned int cpu_uid, u16 *st_index); > int mlx5_st_dealloc_index(struct mlx5_core_dev *dev, u16 st_index); > #else > +static inline int mlx5_st_alloc_index_by_tag(struct mlx5_core_dev *dev, > + u16 tag, u16 *st_index) > +{ > + return -EOPNOTSUPP; > +} > static inline int mlx5_st_alloc_index(struct mlx5_core_dev *dev, > enum tph_mem_type mem_type, > unsigned int cpu_uid, u16 *st_index)
