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From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>,
	Mario.Limonciello@dell.com,
	Michael Jamet <michael.jamet@intel.com>,
	Yehezkel Bernat <YehezkelShB@gmail.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Lukas Wunner <lukas@wunner.de>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org
Subject: [PATCH v8 6/7] PCI: Move resource distribution for a single bridge outside of the loop
Date: Mon, 28 May 2018 15:47:55 +0300	[thread overview]
Message-ID: <20180528124756.78512-7-mika.westerberg@linux.intel.com> (raw)
In-Reply-To: <20180528124756.78512-1-mika.westerberg@linux.intel.com>

There is a special case where there is only single bridge on the bus. In
that case we just assign all resources to it. Currently this is done as
a part of the resource distribution loop but it does not have to be
there, and moving it outside actually improves readability because we
can then save one indent level in the loop.

While there we can add hotplug_bridges == 1 && normal_bridges == 0 to
the same block because they are dealt the same way.

Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/pci/setup-bus.c | 82 ++++++++++++++++++++---------------------
 1 file changed, 41 insertions(+), 41 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 072784f55ea5..79b1824e83b4 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1942,57 +1942,57 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus,
 			remaining_mmio_pref -= resource_size(res);
 	}
 
+	/*
+	 * There is only one bridge on the bus so it gets all available
+	 * resources which it can then distribute to the possible
+	 * hotplug bridges below.
+	 */
+	if (hotplug_bridges + normal_bridges == 1) {
+		dev = list_first_entry(&bus->devices, struct pci_dev, bus_list);
+		if (dev->subordinate) {
+			pci_bus_distribute_available_resources(dev->subordinate,
+				add_list, available_io, available_mmio,
+				available_mmio_pref);
+		}
+		return;
+	}
+
 	/*
 	 * Go over devices on this bus and distribute the remaining
 	 * resource space between hotplug bridges.
 	 */
 	for_each_pci_bridge(dev, bus) {
+		resource_size_t align, io, mmio, mmio_pref;
 		struct pci_bus *b;
 
 		b = dev->subordinate;
-		if (!b)
+		if (!b || !dev->is_hotplug_bridge)
 			continue;
 
-		if (!hotplug_bridges && normal_bridges == 1) {
-			/*
-			 * There is only one bridge on the bus (upstream
-			 * port) so it gets all available resources
-			 * which it can then distribute to the possible
-			 * hotplug bridges below.
-			 */
-			pci_bus_distribute_available_resources(b, add_list,
-				available_io, available_mmio,
-				available_mmio_pref);
-		} else if (dev->is_hotplug_bridge) {
-			resource_size_t align, io, mmio, mmio_pref;
-
-			/*
-			 * Distribute available extra resources equally
-			 * between hotplug-capable downstream ports
-			 * taking alignment into account.
-			 *
-			 * Here hotplug_bridges is always != 0.
-			 */
-			align = pci_resource_alignment(bridge, io_res);
-			io = div64_ul(available_io, hotplug_bridges);
-			io = min(ALIGN(io, align), remaining_io);
-			remaining_io -= io;
-
-			align = pci_resource_alignment(bridge, mmio_res);
-			mmio = div64_ul(available_mmio, hotplug_bridges);
-			mmio = min(ALIGN(mmio, align), remaining_mmio);
-			remaining_mmio -= mmio;
-
-			align = pci_resource_alignment(bridge, mmio_pref_res);
-			mmio_pref = div64_ul(available_mmio_pref,
-					     hotplug_bridges);
-			mmio_pref = min(ALIGN(mmio_pref, align),
-					remaining_mmio_pref);
-			remaining_mmio_pref -= mmio_pref;
-
-			pci_bus_distribute_available_resources(b, add_list, io,
-							       mmio, mmio_pref);
-		}
+		/*
+		 * Distribute available extra resources equally between
+		 * hotplug-capable downstream ports taking alignment into
+		 * account.
+		 *
+		 * Here hotplug_bridges is always != 0.
+		 */
+		align = pci_resource_alignment(bridge, io_res);
+		io = div64_ul(available_io, hotplug_bridges);
+		io = min(ALIGN(io, align), remaining_io);
+		remaining_io -= io;
+
+		align = pci_resource_alignment(bridge, mmio_res);
+		mmio = div64_ul(available_mmio, hotplug_bridges);
+		mmio = min(ALIGN(mmio, align), remaining_mmio);
+		remaining_mmio -= mmio;
+
+		align = pci_resource_alignment(bridge, mmio_pref_res);
+		mmio_pref = div64_ul(available_mmio_pref, hotplug_bridges);
+		mmio_pref = min(ALIGN(mmio_pref, align), remaining_mmio_pref);
+		remaining_mmio_pref -= mmio_pref;
+
+		pci_bus_distribute_available_resources(b, add_list, io, mmio,
+						       mmio_pref);
 	}
 }
 
-- 
2.17.0


  parent reply	other threads:[~2018-05-28 12:47 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-28 12:47 [PATCH v8 0/7] PCI: Fixes and cleanups for native PCIe, SHPC and ACPI hotplug Mika Westerberg
2018-05-28 12:47 ` [PATCH v8 1/7] PCI: Take all bridges into account when calculating bus numbers for extension Mika Westerberg
2018-06-01 13:49   ` Bjorn Helgaas
2018-06-01 13:55     ` Mika Westerberg
2018-05-28 12:47 ` [PATCH v8 2/7] PCI: Introduce shpchp_is_native() Mika Westerberg
2018-05-29  9:06   ` Rafael J. Wysocki
2018-05-29 16:33   ` Andy Shevchenko
2018-05-30 20:23   ` Bjorn Helgaas
2018-05-30 21:55     ` Bjorn Helgaas
2018-05-31  6:58     ` Mika Westerberg
2018-05-31 13:12       ` Bjorn Helgaas
2018-05-31 13:51         ` Mika Westerberg
2018-05-31 16:55           ` Bjorn Helgaas
2018-06-01  9:27             ` Mika Westerberg
2018-06-01 13:25               ` Bjorn Helgaas
2018-05-28 12:47 ` [PATCH v8 3/7] PCI: Introduce hotplug_is_native() Mika Westerberg
2018-05-29  9:06   ` Rafael J. Wysocki
2018-05-29 16:34   ` Andy Shevchenko
2018-05-28 12:47 ` Mika Westerberg [this message]
2018-05-29 17:24   ` [PATCH v8 6/7] PCI: Move resource distribution for a single bridge outside of the loop Andy Shevchenko
2018-05-28 12:47 ` [PATCH v8 7/7] PCI: Document return value of pci_scan_bridge() and pci_scan_bridge_extend() Mika Westerberg
2018-05-29 17:24   ` Andy Shevchenko
2018-05-29 13:26 ` [PATCH v8 0/7] PCI: Fixes and cleanups for native PCIe, SHPC and ACPI hotplug Bjorn Helgaas
2018-05-29 13:41   ` Mika Westerberg
2018-05-29 16:01 ` [PATCH v8 4/7] ACPI/hotplug/PCI: Do not scan all bridges when native PCIe hotplug is used Mika Westerberg
2018-05-29 17:16   ` Andy Shevchenko
2018-06-01 14:11   ` Bjorn Helgaas
2018-06-01 14:24     ` Mika Westerberg
2018-06-01 18:41       ` Bjorn Helgaas
2018-06-01 19:19         ` Mika Westerberg
2018-06-01 21:50           ` Bjorn Helgaas
2018-06-01 22:09             ` Mika Westerberg
2018-06-01 21:35   ` Bjorn Helgaas
2018-06-01 21:48     ` Mika Westerberg
2018-06-02  5:46       ` Bjorn Helgaas
2018-06-02 18:44         ` Mika Westerberg
2018-05-29 16:02 ` [PATCH v8 5/7] ACPI/hotplug/PCI: Mark stale PCI devices disconnected Mika Westerberg
2018-06-02  5:50 ` [PATCH v8 0/7] PCI: Fixes and cleanups for native PCIe, SHPC and ACPI hotplug Bjorn Helgaas
2018-06-02 18:47   ` Mika Westerberg

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