From b6422bc01259aea7e4e11f1cd052e80acdf1275b Mon Sep 17 00:00:00 2001 From: Sebastian Sanchez Date: Sun, 13 Aug 2017 08:08:22 -0700 Subject: [PATCH] IB/hfi1: Check xchg returned value for queuing link down entry Check xchg returned value for queuing link down entry to guarantee proper atomic value reads. Fixes: 626c077c025f ("IB/hfi1: Prevent link down request double queuing") Reviewed-by: Mike Marciniszyn Signed-off-by: Sebastian Sanchez Signed-off-by: Dennis Dalessandro Signed-off-by: Doug Ledford --- drivers/infiniband/hw/hfi1/chip.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/chip.c b/drivers/infiniband/hw/hfi1/chip.c index cbda373..bfb50a4 100644 --- a/drivers/infiniband/hw/hfi1/chip.c +++ b/drivers/infiniband/hw/hfi1/chip.c @@ -7810,16 +7810,22 @@ static void handle_8051_interrupt(struct hfi1_devdata *dd, u32 unused, u64 reg) if (queue_link_down) { /* * if the link is already going down or disabled, do not - * queue another + * queue another. If there's a link down entry already + * queued, don't queue another one. */ if ((ppd->host_link_state & (HLS_GOING_OFFLINE | HLS_LINK_COOLDOWN)) || - ppd->link_enabled == 0 || ppd->is_link_down_queued) { - dd_dev_info(dd, "%s: not queuing link down\n", - __func__); + ppd->link_enabled == 0) { + dd_dev_info(dd, "%s: not queuing link down. host_link_state %x, link_enabled %x\n", + __func__, ppd->host_link_state, + ppd->link_enabled); } else { - xchg(&ppd->is_link_down_queued, 1); - queue_work(ppd->link_wq, &ppd->link_down_work); + if (xchg(&ppd->is_link_down_queued, 1) == 1) + dd_dev_info(dd, + "%s: link down request already queued\n", + __func__); + else + queue_work(ppd->link_wq, &ppd->link_down_work); } } } -- 2.7.4