Re: [PATCH v10 rdma-next] RDMA: Change capability fields in ib_device_attr from int to u32

On Wed, Jul 08, 2026 at 10:51:29PM -0700, Erni Sri Satya Vennela wrote:
> The capability counter fields in struct ib_device_attr are declared
> as signed int, but these values are inherently non-negative. Drivers
> maintain their cached caps as u32 and assign them directly into these
> int fields; if a cap exceeds INT_MAX the implicit narrowing yields a
> negative value visible to the IB core.
> 
> Change the signed int capability fields to u32 to match the
> underlying nature of the data. Also update consumers across the IB
> core, ULPs, NVMe-oF target, RDS, and NFS/RDMA so the new u32 values
> are not forced back through signed int or u8 via min()/min_t() or
> narrowing local variables.
> 
> The nvmet-rdma consumer of max_srq clamps it against
> ib_device.num_comp_vectors, which stays a signed int, so that site
> uses min_t() instead of min() to handle the signed/unsigned mismatch.
> 
> Suggested-by: Jason Gunthorpe <[email protected]>
> Signed-off-by: Erni Sri Satya Vennela <[email protected]>
> Acked-by: Stefan Metzmacher <[email protected]> # smbdirect
> ---
> Changes in v10:
> * Convert max_srq to u32. Use min_t() against the still-signed ib_device.num_comp_vectors.
> * Update commit message.
> * Change rdma_restrack_count() to return u32 and make fill_res_info()'s curr and max u64.
> Changes in v9:
> * Switch the srq_size module parameter accessors to param_get_uint and
>   kstrtouint()/param_set_uint() so they match the now-unsigned
>   nvmet_rdma_srq_size variable.
> Changes in v8:
> * Convert the remaining non-negative counter fields max_ee_rd_atom,
>   max_ee_init_rd_atom, max_ee, max_rdd, max_raw_ipv6_qp and max_srq_wr
>   to u32; keep max_srq as int (its consumer compares it against
>   ib_device.num_comp_vectors, still int).
> * Drop all remaining min_t() where plain min() now works.
> * Make the srq_size module parameters unsigned int so the srq_size min()
>   stays a plain min().
> * Replace the ternary-inside-min() with the simpler "if (x) x--;".
> * Reorder the send_queue_depth min() to min(value, CONST) to match the
>   sibling site.
> * Restore reverse xmas-tree declaration order.
> * Collapse the min()/min3() assignments that now fit onto a single line
>   within 100 columns.
> * Print the now-u32 fields with %u instead of %d.
> Changes in v7:
> * Drop min_t() in all sites where a plain min() (or min3()) works
>   cleanly
> * Guard nvme/host/rdma.c num_inline_segments computation against a
>   device reporting max_send_sge == 0, so the u32 subtract
>   cannot wrap to UINT_MAX.
> * Use %u when printing the newly-u32 capability fields
>   in diagnostic messages.
> Changes in v6:
> * Fix subject prefix: net-next -> rdma-next.
> Changes in v5:
> * Add U8_MAX clamps in iser_verbs, nvme/host, nvme/target, isert,
> * rds/ib_cm, smbdirect/connect and smbdirect/accept where u32 capability
>   fields were directly narrowed into u8 rdma_conn_param fields without
>   clamping.
> * Guard the inline_sge_count calculation in nvmet_rdma_find_get_device()
>   to prevent u32 underflow when both max_sge_rd and max_recv_sge are
> zero.
> * Expand type migration to 9 additional fields (max_mw, max_raw_ethy_qp,
>   max_mcast_grp, max_mcast_qp_attach, max_total_mcast_qp_attach, max_ah,
>   max_srq, max_srq_wr, max_srq_sge)
> * Fix min_t(int,...) in svc_rdma_transport; min_t(u32,...) in ipoib,
>   srpt, nvme/target, rds/ib, rtrs-clt, rtrs-srv, xprtrdma/verbsdd.
> * Fix frwr_ops.c u32 underflow guard (reorder check before subtraction)
> * Change sc_max_send_sges to unsigned int, inline_sge_count to u32
> * Fix %d -> %u in rxe_qp, rxe_srq, ipoib_cm, ib_isert,
> * svc_rdma_transport
> * Update commit message.
> Changes in v4:
> * Drop clamping the values in mana_ib_query_device, instead update
>   the props values from int to u32.
> Changes in v3:
> * Drop clamping from mana_ib_gd_query_adapter_caps(). The internal u32
>   caps cache does not need to be clamped.
> * Move all clamping exclusively to mana_ib_query_device(), which is the
>   only place the cached u32 values are narrowed into the signed int
>   fields of struct ib_device_attr.
> * Reframe commit message: this is a u32-to-int type boundary fix, not a
>   CVM/untrusted-hardware hardening patch.
> Changes in v2:
> * Update patch title.
> ---
>  drivers/infiniband/core/cq.c               |  3 +-
>  drivers/infiniband/core/nldev.c            |  3 +-
>  drivers/infiniband/core/restrack.c         |  2 +-
>  drivers/infiniband/hw/qedr/verbs.c         |  2 +-
>  drivers/infiniband/sw/rxe/rxe_qp.c         | 22 ++++-----
>  drivers/infiniband/sw/rxe/rxe_srq.c        | 16 +++----
>  drivers/infiniband/ulp/ipoib/ipoib_cm.c    | 10 ++---
>  drivers/infiniband/ulp/ipoib/ipoib_verbs.c |  3 +-
>  drivers/infiniband/ulp/iser/iser_verbs.c   |  5 +--
>  drivers/infiniband/ulp/isert/ib_isert.c    |  7 ++-
>  drivers/infiniband/ulp/rtrs/rtrs-clt.c     | 11 ++---
>  drivers/infiniband/ulp/rtrs/rtrs-srv.c     | 11 ++---
>  drivers/infiniband/ulp/srp/ib_srp.c        |  2 +-
>  drivers/infiniband/ulp/srpt/ib_srpt.c      | 21 +++++----
>  drivers/nvme/host/rdma.c                   |  8 ++--
>  drivers/nvme/target/rdma.c                 | 26 ++++++-----
>  fs/smb/smbdirect/accept.c                  |  5 ++-
>  fs/smb/smbdirect/connect.c                 |  5 ++-
>  fs/smb/smbdirect/connection.c              |  8 ++--
>  include/linux/sunrpc/svc_rdma.h            |  4 +-
>  include/rdma/ib_verbs.h                    | 52 +++++++++++-----------
>  include/rdma/restrack.h                    |  2 +-
>  net/rds/ib.c                               | 10 ++---
>  net/rds/ib_cm.c                            | 10 ++---
>  net/sunrpc/xprtrdma/frwr_ops.c             |  7 +--
>  net/sunrpc/xprtrdma/svc_rdma_transport.c   |  5 +--
>  net/sunrpc/xprtrdma/verbs.c                |  2 +-
>  27 files changed, 129 insertions(+), 133 deletions(-)

This patch touches too many areas to delay it further. Let's merge it
now and improve it later, if needed.

Thanks