From 64044bcf75063cb5a6d42712886a712449df2ce3 Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Wed, 9 Nov 2005 12:23:17 -0800 Subject: [PATCH] [IB] mthca: fix wraparound handling in mthca_cq_clean() Handle case where prod_index has wrapped around and become less than cq->cons_index by checking that their difference as a signed int is positive rather than comparing directly. Signed-off-by: Roland Dreier --- drivers/infiniband/hw/mthca/mthca_cq.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/drivers/infiniband/hw/mthca/mthca_cq.c b/drivers/infiniband/hw/mthca/mthca_cq.c index f98e2355582..4a8adcef207 100644 --- a/drivers/infiniband/hw/mthca/mthca_cq.c +++ b/drivers/infiniband/hw/mthca/mthca_cq.c @@ -258,7 +258,7 @@ void mthca_cq_clean(struct mthca_dev *dev, u32 cqn, u32 qpn, { struct mthca_cq *cq; struct mthca_cqe *cqe; - int prod_index; + u32 prod_index; int nfreed = 0; spin_lock_irq(&dev->cq_table.lock); @@ -293,19 +293,15 @@ void mthca_cq_clean(struct mthca_dev *dev, u32 cqn, u32 qpn, * Now sweep backwards through the CQ, removing CQ entries * that match our QP by copying older entries on top of them. */ - while (prod_index > cq->cons_index) { - cqe = get_cqe(cq, (prod_index - 1) & cq->ibcq.cqe); + while ((int) --prod_index - (int) cq->cons_index >= 0) { + cqe = get_cqe(cq, prod_index & cq->ibcq.cqe); if (cqe->my_qpn == cpu_to_be32(qpn)) { if (srq) mthca_free_srq_wqe(srq, be32_to_cpu(cqe->wqe)); ++nfreed; - } - else if (nfreed) - memcpy(get_cqe(cq, (prod_index - 1 + nfreed) & - cq->ibcq.cqe), - cqe, - MTHCA_CQ_ENTRY_SIZE); - --prod_index; + } else if (nfreed) + memcpy(get_cqe(cq, (prod_index + nfreed) & cq->ibcq.cqe), + cqe, MTHCA_CQ_ENTRY_SIZE); } if (nfreed) { -- 2.20.1