From d5df7688b6a36dbb5611a58229a5e294cd978999 Mon Sep 17 00:00:00 2001 From: Manish Chopra Date: Fri, 14 Oct 2016 05:19:23 -0400 Subject: [PATCH] qed: Fix possible race when reading firmware return code. While handling SPQ ramrod completion, there is a possible race where driver might not read updated fw return code based on ramrod completion done. This patch ensures that fw return code is written first and then completion done flag is updated using appropriate memory barriers. Signed-off-by: Manish Chopra Signed-off-by: Yuval Mintz Signed-off-by: David S. Miller --- drivers/net/ethernet/qlogic/qed/qed_sp.h | 4 ++-- drivers/net/ethernet/qlogic/qed/qed_spq.c | 12 ++++++------ 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/qlogic/qed/qed_sp.h b/drivers/net/ethernet/qlogic/qed/qed_sp.h index 652c90819758..27c450fd2193 100644 --- a/drivers/net/ethernet/qlogic/qed/qed_sp.h +++ b/drivers/net/ethernet/qlogic/qed/qed_sp.h @@ -111,8 +111,8 @@ union qed_spq_req_comp { }; struct qed_spq_comp_done { - u64 done; - u8 fw_return_code; + unsigned int done; + u8 fw_return_code; }; struct qed_spq_entry { diff --git a/drivers/net/ethernet/qlogic/qed/qed_spq.c b/drivers/net/ethernet/qlogic/qed/qed_spq.c index 259a6156c761..6c05402ea4dc 100644 --- a/drivers/net/ethernet/qlogic/qed/qed_spq.c +++ b/drivers/net/ethernet/qlogic/qed/qed_spq.c @@ -54,11 +54,10 @@ static void qed_spq_blocking_cb(struct qed_hwfn *p_hwfn, comp_done = (struct qed_spq_comp_done *)cookie; - comp_done->done = 0x1; - comp_done->fw_return_code = fw_return_code; + comp_done->fw_return_code = fw_return_code; - /* make update visible to waiting thread */ - smp_wmb(); + /* Make sure completion done is visible on waiting thread */ + smp_store_release(&comp_done->done, 0x1); } static int __qed_spq_block(struct qed_hwfn *p_hwfn, @@ -74,8 +73,9 @@ static int __qed_spq_block(struct qed_hwfn *p_hwfn, while (iter_cnt--) { /* Validate we receive completion update */ - smp_rmb(); - if (comp_done->done == 1) { + if (READ_ONCE(comp_done->done) == 1) { + /* Read updated FW return value */ + smp_read_barrier_depends(); if (p_fw_ret) *p_fw_ret = comp_done->fw_return_code; return 0; -- 2.39.5