From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ursula Braun , "David S . Miller" , Sasha Levin , linux-s390@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 24/68] s390/ism: clear dmbe_mask bit before SMC IRQ handling Date: Thu, 29 Nov 2018 00:55:15 -0500 Message-Id: <20181129055559.159228-24-sashal@kernel.org> In-Reply-To: <20181129055559.159228-1-sashal@kernel.org> References: <20181129055559.159228-1-sashal@kernel.org> List-ID: From: Ursula Braun [ Upstream commit 007b656851ed7f94ba0fa358ac3e5d7705da6846 ] SMC-D stress workload showed connection stalls. Since the firmware decides to skip raising an interrupt if the SBA DMBE mask bit is still set, this SBA DMBE mask bit should be cleared before the IRQ handling in the SMC code runs. Otherwise there are small windows possible with missing interrupts for incoming data. SMC-D currently does not care about the old value of the SBA DMBE mask. Acked-by: Sebastian Ott Signed-off-by: Ursula Braun Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/s390/net/ism_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c index c0631895154e..8684bcec8ff4 100644 --- a/drivers/s390/net/ism_drv.c +++ b/drivers/s390/net/ism_drv.c @@ -415,9 +415,9 @@ static irqreturn_t ism_handle_irq(int irq, void *data) break; clear_bit_inv(bit, bv); + ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET] = 0; barrier(); smcd_handle_irq(ism->smcd, bit + ISM_DMB_BIT_OFFSET); - ism->sba->dmbe_mask[bit + ISM_DMB_BIT_OFFSET] = 0; } if (ism->sba->e) { -- 2.17.1