From 007b656851ed7f94ba0fa358ac3e5d7705da6846 Mon Sep 17 00:00:00 2001 From: Ursula Braun Date: Mon, 12 Nov 2018 17:06:12 +0100 Subject: [PATCH] s390/ism: clear dmbe_mask bit before SMC IRQ handling 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 --- 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 f96ec68af2e5..dcbf5c857743 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) {