From: Robin Murphy <robin.murphy@arm.com>
Date: Tue, 5 Apr 2022 14:40:55 +0100
Subject: sfc: Stop using iommu_present()
Patch-mainline: v5.19-rc1
Git-commit: 6a62924c0a81316b2aff713566593405b57545d5
References: jsc#PED-1565

Even if an IOMMU might be present for some PCI segment in the system,
that doesn't necessarily mean it provides translation for the device
we care about. It appears that what we care about here is specifically
whether DMA mapping ops involve any IOMMU overhead or not, so check for
translation actually being active for our device.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
Link: https://lore.kernel.org/r/7350f957944ecfce6cce90f422e3992a1f428775.1649166055.git.robin.murphy@arm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/sfc/falcon/rx.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/sfc/falcon/rx.c
+++ b/drivers/net/ethernet/sfc/falcon/rx.c
@@ -718,12 +718,14 @@ static void ef4_init_rx_recycle_ring(str
 				     struct ef4_rx_queue *rx_queue)
 {
 	unsigned int bufs_in_recycle_ring, page_ring_size;
+	struct iommu_domain __maybe_unused *domain;
 
 	/* Set the RX recycle ring size */
 #ifdef CONFIG_PPC64
 	bufs_in_recycle_ring = EF4_RECYCLE_RING_SIZE_IOMMU;
 #else
-	if (iommu_present(&pci_bus_type))
+	domain = iommu_get_domain_for_dev(&efx->pci_dev->dev);
+	if (domain && domain->type != IOMMU_DOMAIN_IDENTITY)
 		bufs_in_recycle_ring = EF4_RECYCLE_RING_SIZE_IOMMU;
 	else
 		bufs_in_recycle_ring = EF4_RECYCLE_RING_SIZE_NOIOMMU;