linux-kernel - [PATCH v2 4/4] PCI: Introduce ALIGN_DOWN_IF

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Date: Fri, 14 Jun 2024 13:06:06 +0300
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: linux-pci@...r.kernel.org,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Jonathan Cameron <Jonathan.Cameron@...wei.com>,
	Philipp Stanner <pstanner@...hat.com>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Wilczyński <kw@...ux.com>,
	linux-kernel@...r.kernel.org
Cc: Jonathan Hunter <jonathanh@...dia.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-tegra@...r.kernel.org,
	Robert Richter <rric@...nel.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [PATCH v2 4/4] PCI: Introduce ALIGN_DOWN_IF_NONZERO() helper locally

pci_bus_distribute_available_resources() performs alignment in case of
non-zero alignment requirement on 3 occasions. Introduce
ALIGN_DOWN_IF_NONZERO() helper to avoid coding the non-zero check 3
times.

Suggested-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
---

I tried to look other similar cases for both ALIGN() and ALIGN_DOWN()
kernel-wide but it seems this is not very common so I did not put
ALIGN_DOWN_IF_NONZERO() into the generic header.
---
 drivers/pci/setup-bus.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 004405edf290..39552d1a1793 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1819,6 +1819,9 @@ static void remove_dev_resources(struct pci_dev *dev, struct resource *io,
 	}
 }
 
+#define ALIGN_DOWN_IF_NONZERO(addr, align) \
+			((align) ? ALIGN_DOWN((addr), (align)) : (addr))
+
 /*
  * io, mmio and mmio_pref contain the total amount of bridge window space
  * available. This includes the minimal space needed to cover all the
@@ -1930,8 +1933,7 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
 		 * what is available).
 		 */
 		align = pci_resource_alignment(dev, res);
-		resource_set_size(&io, align ? ALIGN_DOWN(io_per_b, align)
-					     : io_per_b);
+		resource_set_size(&io, ALIGN_DOWN_IF_NONZERO(io_per_b, align));
 
 		/*
 		 * The x_per_b holds the extra resource space that can be
@@ -1943,15 +1945,13 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
 
 		res = &dev->resource[PCI_BRIDGE_MEM_WINDOW];
 		align = pci_resource_alignment(dev, res);
-		resource_set_size(&mmio, align ? ALIGN_DOWN(mmio_per_b, align)
-					       : mmio_per_b);
+		resource_set_size(&mmio, ALIGN_DOWN_IF_NONZERO(mmio_per_b, align));
 		mmio.start -= resource_size(res);
 
 		res = &dev->resource[PCI_BRIDGE_PREF_MEM_WINDOW];
 		align = pci_resource_alignment(dev, res);
 		resource_set_size(&mmio_pref,
-				  align ? ALIGN_DOWN(mmio_pref_per_b, align)
-					: mmio_pref_per_b);
+				  ALIGN_DOWN_IF_NONZERO(mmio_pref_per_b, align));
 		mmio_pref.start -= resource_size(res);
 
 		pci_bus_distribute_available_resources(b, add_list, io, mmio,
-- 
2.39.2