linux-kernel - [PATCH 1/3] PCI: dwc: ep: Return after clearing BAR-match inbound mapping

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Message-ID: <20260131133655.218018-2-den@valinux.co.jp>
Date: Sat, 31 Jan 2026 22:36:53 +0900
From: Koichiro Den <den@...inux.co.jp>
To: mani@...nel.org,
	cassel@...nel.org,
	kwilczynski@...nel.org,
	kishon@...nel.org,
	bhelgaas@...gle.com,
	corbet@....net,
	jingoohan1@...il.com,
	lpieralisi@...nel.org,
	robh@...nel.org,
	Frank.Li@....com
Cc: linux-pci@...r.kernel.org,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] PCI: dwc: ep: Return after clearing BAR-match inbound mapping

dw_pcie_ep_clear_ib_maps() first checks whether the inbound mapping for
a BAR is in BAR Match Mode (tracked via ep_func->bar_to_atu[bar]). Once
found, the iATU region is disabled and the bookkeeping is cleared.

BAR Match Mode and Address Match Mode mappings are mutually exclusive
for a given BAR, so there is nothing left for the Address Match Mode
teardown path to do after the BAR Match Mode mapping has been removed.

Return early after clearing the BAR Match Mode mapping to avoid running
the Address Match Mode teardown path. This makes the helper's intention
explicit and helps detect incorrect use of pci_epc_set_bar().

Link: https://lore.kernel.org/all/aXtrW7viGZfMNZur@ryzen/
Suggested-by: Niklas Cassel <cassel@...nel.org>
Signed-off-by: Koichiro Den <den@...inux.co.jp>
---
 drivers/pci/controller/dwc/pcie-designware-ep.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 7e7844ff0f7e..0ca05943a1e5 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -165,6 +165,7 @@ static void dw_pcie_ep_clear_ib_maps(struct dw_pcie_ep *ep, u8 func_no, enum pci
 		dw_pcie_disable_atu(pci, PCIE_ATU_REGION_DIR_IB, atu_index);
 		clear_bit(atu_index, ep->ib_window_map);
 		ep_func->bar_to_atu[bar] = 0;
+		return;
 	}

 	/* Tear down all Address Match Mode mappings, if any. */
-- 
2.51.0