rxe: Fix dma.length computation in wr_set_sge_list#1744
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wr_set_sge_list() summed the SGE lengths with a loop that never advanced sg_list: while (num_sge--) tot_length += sg_list->length; so tot_length ended up as num_sge * sg_list[0].length instead of the true sum, and wqe->dma.length / wqe->dma.resid were written with that wrong value. The per-SGE entries themselves were unaffected because they are populated by the preceding memcpy(). The kernel rxe driver requires dma.length == sum(sge[i].length) and enforces it in rxe_mr.c:copy_data(), so a multi-SGE WR posted through the ibv_qp_ex builder API (ibv_wr_set_sge_list) on rxe completes with IB_WC_LOC_PROT_ERR once finish_packet()/copy_data() runs off the end of the SGE list. The legacy ibv_post_send path (init_send_wqe) is unaffected; it sums the lengths with an indexed for loop. Fix by computing the total with an indexed loop, matching the style already used in rxe_post_one_recv() and init_send_wqe() in this file. Fixes: 1a894ca ("Providers/rxe: Implement ibv_create_qp_ex verb") Signed-off-by: Jared Holzman <jholzman@nvidia.com>
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wr_set_sge_list() summed the SGE lengths with a loop that never advanced sg_list:
so tot_length ended up as num_sge * sg_list[0].length instead of the true sum, and wqe->dma.length / wqe->dma.resid were written with that wrong value. The per-SGE entries themselves were unaffected because they are populated by the preceding memcpy().
The kernel rxe driver requires dma.length == sum(sge[i].length) and enforces it in rxe_mr.c:copy_data(), so a multi-SGE WR posted through the ibv_qp_ex builder API (ibv_wr_set_sge_list) on rxe completes with IB_WC_LOC_PROT_ERR once finish_packet()/copy_data() runs off the end of the SGE list.
The legacy ibv_post_send path (init_send_wqe) is unaffected; it sums the lengths with an indexed for loop.
Fix by computing the total with an indexed loop, matching the style already used in rxe_post_one_recv() and init_send_wqe() in this file.
Fixes: 1a894ca ("Providers/rxe: Implement ibv_create_qp_ex verb")