FAILED: patch "[PATCH] PCI: dwc: Move interrupt acking into the proper callback" failed to apply to 4.14-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 3f7bb2ec20ce07c02b2002349d256c91a463fcc5 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@xxxxxxx>
Date: Tue, 13 Nov 2018 22:57:34 +0000
Subject: [PATCH] PCI: dwc: Move interrupt acking into the proper callback

The write to the status register is really an ACK for the HW,
and should be treated as such by the driver. Let's move it to the
irq_ack() callback, which will prevent people from moving it around
in order to paper over other bugs.

Fixes: 8c934095fa2f ("PCI: dwc: Clear MSI interrupt status after it is handled,
not before")
Fixes: 7c5925afbc58 ("PCI: dwc: Move MSI IRQs allocation to IRQ domains
hierarchical API")
Link: https://lore.kernel.org/linux-pci/20181113225734.8026-1-marc.zyngier@xxxxxxx/
Reported-by: Trent Piepho <tpiepho@xxxxxxxxxx>
Tested-by: Niklas Cassel <niklas.cassel@xxxxxxxxxx>
Tested-by: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
Tested-by: Stanimir Varbanov <svarbanov@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
[lorenzo.pieralisi@xxxxxxx: updated commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 610a5e018d27..0fa9e8fdce66 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -99,9 +99,6 @@ irqreturn_t dw_handle_msi_irq(struct pcie_port *pp)
 					       (i * MAX_MSI_IRQS_PER_CTRL) +
 					       pos);
 			generic_handle_irq(irq);
-			dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS +
-						(i * MSI_REG_CTRL_BLOCK_SIZE),
-					    4, 1 << pos);
 			pos++;
 		}
 	}
@@ -200,14 +197,18 @@ static void dw_pci_bottom_unmask(struct irq_data *data)
 
 static void dw_pci_bottom_ack(struct irq_data *d)
 {
-	struct msi_desc *msi = irq_data_get_msi_desc(d);
-	struct pcie_port *pp;
+	struct pcie_port *pp  = irq_data_get_irq_chip_data(d);
+	unsigned int res, bit, ctrl;
 	unsigned long flags;
 
-	pp = msi_desc_to_pci_sysdata(msi);
+	ctrl = d->hwirq / MAX_MSI_IRQS_PER_CTRL;
+	res = ctrl * MSI_REG_CTRL_BLOCK_SIZE;
+	bit = d->hwirq % MAX_MSI_IRQS_PER_CTRL;
 
 	raw_spin_lock_irqsave(&pp->lock, flags);
 
+	dw_pcie_wr_own_conf(pp, PCIE_MSI_INTR0_STATUS + res, 4, 1 << bit);
+
 	if (pp->ops->msi_irq_ack)
 		pp->ops->msi_irq_ack(d->hwirq, pp);