mlx5: Fix inline-scatter source address on 128B CQE REQ completions#1743
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yishaih wants to merge 1 commit into
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mlx5: Fix inline-scatter source address on 128B CQE REQ completions#1743yishaih wants to merge 1 commit into
yishaih wants to merge 1 commit into
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In mlx5_parse_cqe() the inline-scatter completion path used the function's void* buffer pointer to address the inline data: if (cqe64->op_own & MLX5_INLINE_SCATTER_32) err = mlx5_copy_to_send_wqe(mqp, wqe_ctr, cqe, ...); else if (cqe64->op_own & MLX5_INLINE_SCATTER_64) err = mlx5_copy_to_send_wqe(mqp, wqe_ctr, cqe - 1, ...); `cqe` is the base of the CQE buffer entry, while `cqe64` points at the 64B descriptor inside that entry (offset 0 for a 64B entry, offset 64 for a 128B entry). Both call sites used the wrong base: 1. SCATTER_64: the payload occupies the first 64B of a 128B entry, so the correct base is `cqe64 - 1`. The existing `cqe - 1` relied on void* pointer arithmetic (a GNU extension that subtracts one byte, not one descriptor) and so was off by 63 bytes. 2. SCATTER_32: the inline_32 payload starts at offset 0 of the descriptor, so the correct base is `cqe64`. Passing `cqe` instead reads from offset 0 of the buffer entry, which on a 128B CQE is 64 bytes before the payload (the tail of the previous entry). For 64B CQEs cqe == cqe64 so the bug was masked. Both bugs affect inline RDMA_READ / ATOMIC completions on the legacy ibv_poll_cq path and the extended-CQ ibv_start_poll / ibv_next_poll path. The matching responder helpers (handle_responder, handle_responder_lazy, handle_tag_matching) already pass the typed cqe64 pointer and so were not affected. Use cqe64 / cqe64 - 1 at the REQ-path call sites. The void* cqe parameter was only used here, so drop it from mlx5_get_next_cqe(), mlx5_parse_cqe(), mlx5_parse_lazy_cqe() and the locals in mlx5_poll_one(), mlx5_start_poll() and mlx5_next_poll(). Fixes: 8c4791a ("libmlx5: First version of libmlx5") Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
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Fix inline-scatter source address on 128B CQE REQ completions.
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