RDMA/cxgb4: Replace 0-length arrays with flexible arrays

Zero-length arrays are deprecated[1]. Replace all remaining
0-length arrays with flexible arrays. Detected with GCC 13, using
-fstrict-flex-arrays=3:

In function 'build_rdma_write',
inlined from 'c4iw_post_send' at ../drivers/infiniband/hw/cxgb4/qp.c:1173:10:
../drivers/infiniband/hw/cxgb4/qp.c:597:38: warning: array subscript 0 is outside array bounds of 'struct fw_ri_immd[0]' [-Warray-bounds=]
597 | wqe->write.u.immd_src[0].r2 = 0;
| ~~~~~~~~~~~~~~~~~~~~~^~~
../drivers/infiniband/hw/cxgb4/t4fw_ri_api.h: In function 'c4iw_post_send':
../drivers/infiniband/hw/cxgb4/t4fw_ri_api.h:567:35: note: while referencing 'immd_src'
567 | struct fw_ri_immd immd_src[0];
| ^~~~~~~~

Additionally drop the unused C99_NOT_SUPPORTED ifndef lines.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays

Cc: Potnuri Bharat Teja <bharat@chelsio.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230105223225.never.252-kees@kernel.org
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Leon Romanovsky <leon@kernel.org>

RDMA: Replace zero-length array with flexible-array member

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Link: https://lore.kernel.org/r/20200213010425.GA13068@embeddedor.com
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> # added a few more

iw_cxgb4: Support FW write completion WR

To optimize NVME-oF READ IOPs, use a specialized WQE that combines
the RDMA WRITE and SEND_INV WR chain submitted by the NVME-oF target
driver.

This reduces uP overhead per NVME-oF IO, and results in over 10%
improvement in NVME-oF 4K READ IOPs.

Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

iw_cxgb4: RDMA write with immediate support

Adds iw_cxgb4 functionality to support RDMA_WRITE_WITH_IMMEDATE opcode.

Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

rdma/cxgb4: Add support for srq functions & structs

This patch adds kernel mode t4_srq structures and support functions,
uapi structures and defines, as well as firmware work request structures.

Signed-off-by: Raju Rangoju <rajur@chelsio.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

RDMA/cxgb4: Annotate r2 and stag as __be32

Chelsio cxgb4 HW is big-endian, hence there is need to properly
annotate r2 and stag fields as __be32 and not __u32 to fix the
following sparse warnings.

drivers/infiniband/hw/cxgb4/qp.c:614:16:
warning: incorrect type in assignment (different base types)
expected unsigned int [unsigned] [usertype] r2
got restricted __be32 [usertype] <noident>
drivers/infiniband/hw/cxgb4/qp.c:615:18:
warning: incorrect type in assignment (different base types)
expected unsigned int [unsigned] [usertype] stag
got restricted __be32 [usertype] <noident>

Cc: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

iw_cxgb4: add fast-path for small REG_MR operations

When processing a REG_MR work request, if fw supports the
FW_RI_NSMR_TPTE_WR work request, and if the page list for this
registration is <= 2 pages, and the current state of the mr is INVALID,
then use FW_RI_NSMR_TPTE_WR to pass down a fully populated TPTE for FW
to write. This avoids FW having to do an async read of the TPTE blocking
the SQ until the read completes.

To know if the current MR state is INVALID or not, iw_cxgb4 must track the
state of each fastreg MR. The c4iw_mr struct state is updated as REG_MR
and LOCAL_INV WRs are posted and completed, when a reg_mr is destroyed,
and when RECV completions are processed that include a local invalidation.

This optimization increases small IO IOPS for both iSER and NVMF.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

cxgb4, iw_cxgb4: move delayed ack macro definitions

move delayed ack macro definitions to common
header file t4_msg.h.

Signed-off-by: Varun Prakash <varun@chelsio.com>
Acked-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

cxgb4, iw_cxgb4, cxgb4i: remove duplicate definitions

move struct ulptx_idata definition to
common header file t4_msg.h.

Signed-off-by: Varun Prakash <varun@chelsio.com>
Acked-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

cxgb4, iw_cxgb4: move definitions to common header file

move struct tcp_options, struct cpl_pass_accept_req,
enum defining congestion control algorithms
and associated macros to common header file t4_msg.h

Signed-off-by: Varun Prakash <varun@chelsio.com>
Acked-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

iw_cxgb4: Cleanup register defines/MACROS

Cleanup macros and register defines for consistency

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

iw_cxgb4: Cleanup register defines/MACROS defined in t4fw_ri_api.h

Cleanup all the MACROS that are defined in t4fw_ri_api.h and affected files

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

iw_cxgb4: Cleanup register defines/MACROS defined in t4fw_ri_api.h

Cleanup all the MACROS that are defined in t4fw_ri_api.h and affected files

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

cxgb4/iw_cxgb4: Move common defines to cxgb4

This define is used by cxgb4i and iw_cxgb4, moving to avoid code duplication

Signed-off-by: Anish Bhatt <anish@chelsio.com>
Acked-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

iw_cxgb4: Choose appropriate hw mtu index and ISS for iWARP connections

Select the appropriate hw mtu index and initial sequence number to optimize
hw memory performance.

Add new cxgb4_best_aligned_mtu() which allows callers to provide enough
information to be used to [possibly] select an MTU which will result in the
TCP Data Segment Size (AKA Maximum Segment Size) to be an aligned value.

If an RTR message exhange is required, then align the ISS to 8B - 1 + 4, so
that after the SYN the send seqno will align on a 4B boundary. The RTR
message exchange will leave the send seqno aligned on an 8B boundary.
If an RTR is not required, then align the ISS to 8B - 1. The goal is
to have the send seqno be 8B aligned when we send the first FPDU.

Based on original work by Casey Leedom <leeedom@chelsio.com> and
Steve Wise <swise@opengridcomputing.com>

Signed-off-by: Casey Leedom <leedom@chelsio.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

RDMA/cxgb4: Force T5 connections to use TAHOE congestion control

This is required to work around a T5 HW issue.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

RDMA/cxgb4: Add module option to tweak delayed ack

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

RDMA/cxgb4: Add driver for Chelsio T4 RNIC

Add an RDMA/iWARP driver for Chelsio T4 Ethernet adapters.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>