On 5/13/2026 2:47 AM, Zhiping Zhang wrote: > Query dma-buf TPH metadata when registering a dma-buf MR for peer to > peer access and translate the raw steering tag into an mlx5 steering > tag index. Factor mlx5_st_alloc_index() so callers that already have a > raw steering tag can allocate the corresponding mlx5 index directly. > Keep the DMAH path as the first priority and only fall back to dma-buf > metadata when no DMAH is supplied. > > Add pcie_tph_get_st_width() so the mlx5 IB driver can query the > device's negotiated ST width without poking pci_dev::tph_req_type > directly (that field is gated by CONFIG_PCIE_TPH and would otherwise > break !CONFIG_PCIE_TPH builds). Pass the width to the dma-buf > get_tph() callback so the exporter can return the value that matches > the consumer's capability.
1\ Recommend the PCI/TPH modification be committed separately. 2\ How about rename it to pcie_tph_enabled_req_type() ? so we could use already defined macro: #define PCI_TPH_REQ_DISABLE 0x0 /* No TPH requests allowed */ #define PCI_TPH_REQ_TPH_ONLY 0x1 /* TPH only requests allowed */ #define PCI_TPH_REQ_EXT_TPH 0x3 /* Extended TPH requests allowed */ > > Pass the dma_buf pointer that the umem already resolved into > get_tph_mr_dmabuf() instead of re-resolving the user-supplied fd. > Re-resolving opens a TOCTOU where a concurrent dup2() can substitute a > different dma_buf between umem creation and TPH lookup. > > Track the per-MR ownership of the allocated mlx5 ST index on > mlx5_ib_mr (dmabuf_st_index / dmabuf_st_owned) and release it once the > firmware mkey no longer references it. Both the cached path > (mlx5r_umr_revoke_mr_with_lock + ib_frmr_pool_push) and the > destroy_mkey path call mlx5_ib_mr_put_dmabuf_st() so the ST index does > not leak when the MR is reused from the FRMR pool. > > Initialize ret in mlx5_st_create() so the cached steering-tag path > returns success cleanly under clang builds. > > Signed-off-by: Zhiping Zhang <[email protected]> > --- > drivers/infiniband/hw/mlx5/mlx5_ib.h | 6 ++ > drivers/infiniband/hw/mlx5/mr.c | 72 ++++++++++++++++++- > .../net/ethernet/mellanox/mlx5/core/lib/st.c | 27 ++++--- > drivers/pci/tph.c | 20 ++++++ > include/linux/mlx5/driver.h | 7 ++ > include/linux/pci-tph.h | 2 + > 6 files changed, 124 insertions(+), 10 deletions(-) > ...
