From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sebastian Ott , Ursula Braun , "David S. Miller" , Sasha Levin Subject: [PATCH 4.19 024/118] s390/ism: clear dmbe_mask bit before SMC IRQ handling Date: Tue, 11 Dec 2018 16:40:43 +0100 Message-Id: <20181211151645.219854857@linuxfoundation.org> In-Reply-To: <20181211151644.216668863@linuxfoundation.org> References: <20181211151644.216668863@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit List-ID: 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ [ 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) { -- 2.19.1