From 965f5593933f545b79b2de1d9710ef5b14c2f27b Mon Sep 17 00:00:00 2001 From: Bob Pearson Date: Tue, 13 Oct 2020 12:07:42 -0500 Subject: [PATCH] RDMA/rxe: Compute PSN windows correctly [ Upstream commit bb3ab2979fd69db23328691cb10067861df89037 ] The code which limited the number of unacknowledged PSNs was incorrect. The PSNs are limited to 24 bits and wrap back to zero from 0x00ffffff. The test was computing a 32 bit value which wraps at 32 bits so that qp->req.psn can appear smaller than the limit when it is actually larger. Replace '>' test with psn_compare which is used for other PSN comparisons and correctly handles the 24 bit size. Fixes: 8700e3e7c485 ("Soft RoCE driver") Link: https://lore.kernel.org/r/20201013170741.3590-1-rpearson@hpe.com Signed-off-by: Bob Pearson Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin --- drivers/infiniband/sw/rxe/rxe_req.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c index af3923bf0a36..d4917646641a 100644 --- a/drivers/infiniband/sw/rxe/rxe_req.c +++ b/drivers/infiniband/sw/rxe/rxe_req.c @@ -634,7 +634,8 @@ next_wqe: } if (unlikely(qp_type(qp) == IB_QPT_RC && - qp->req.psn > (qp->comp.psn + RXE_MAX_UNACKED_PSNS))) { + psn_compare(qp->req.psn, (qp->comp.psn + + RXE_MAX_UNACKED_PSNS)) > 0)) { qp->req.wait_psn = 1; goto exit; } -- 2.17.1