linux-kernel - [PATCH v6 2/8] PCI/VGA: Deal only with VGA class devices

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Message-Id: <20230612192550.197053-3-15330273260@189.cn>
Date:   Tue, 13 Jun 2023 03:25:44 +0800
From:   Sui Jingfeng <15330273260@....cn>
To:     Alex Deucher <alexander.deucher@....com>,
        Christian Konig <christian.koenig@....com>,
        Pan Xinhui <Xinhui.Pan@....com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
        Ben Skeggs <bskeggs@...hat.com>,
        Karol Herbst <kherbst@...hat.com>,
        Lyude Paul <lyude@...hat.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Hawking Zhang <Hawking.Zhang@....com>,
        Mario Limonciello <mario.limonciello@....com>,
        Lijo Lazar <lijo.lazar@....com>,
        YiPeng Chai <YiPeng.Chai@....com>,
        Andrey Grodzovsky <andrey.grodzovsky@....com>,
        Somalapuram Amaranath <Amaranath.Somalapuram@....com>,
        Bokun Zhang <Bokun.Zhang@....com>,
        Ville Syrjala <ville.syrjala@...ux.intel.com>,
        Li Yi <liyi@...ngson.cn>,
        Sui Jingfeng <suijingfeng@...ngson.cn>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Kevin Tian <kevin.tian@...el.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Yishai Hadas <yishaih@...dia.com>,
        Abhishek Sahu <abhsahu@...dia.com>, Yi Liu <yi.l.liu@...el.com>
Cc:     amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
        nouveau@...ts.freedesktop.org, linux-pci@...r.kernel.org,
        kvm@...r.kernel.org, loongson-kernel@...ts.loongnix.cn
Subject: [PATCH v6 2/8] PCI/VGA: Deal only with VGA class devices

From: Sui Jingfeng <suijingfeng@...ngson.cn>

Deal only with the VGA devcie(pdev->class == 0x0300), so replace the
pci_get_subsys() function with pci_get_class(). Filter the non-PCI display
device(pdev->class != 0x0300) out. There no need to process the non-display
PCI device.

Signed-off-by: Sui Jingfeng <suijingfeng@...ngson.cn>
---
 drivers/pci/vgaarb.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/vgaarb.c b/drivers/pci/vgaarb.c
index c1bc6c983932..22a505e877dc 100644
--- a/drivers/pci/vgaarb.c
+++ b/drivers/pci/vgaarb.c
@@ -754,10 +754,6 @@ static bool vga_arbiter_add_pci_device(struct pci_dev *pdev)
 	struct pci_dev *bridge;
 	u16 cmd;
 
-	/* Only deal with VGA class devices */
-	if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
-		return false;
-
 	/* Allocate structure */
 	vgadev = kzalloc(sizeof(struct vga_device), GFP_KERNEL);
 	if (vgadev == NULL) {
@@ -1500,7 +1496,9 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
 	struct pci_dev *pdev = to_pci_dev(dev);
 	bool notify = false;
 
-	vgaarb_dbg(dev, "%s\n", __func__);
+	/* Only deal with VGA class devices */
+	if (pdev->class != PCI_CLASS_DISPLAY_VGA << 8)
+		return 0;
 
 	/* For now we're only intereted in devices added and removed. I didn't
 	 * test this thing here, so someone needs to double check for the
@@ -1510,6 +1508,8 @@ static int pci_notify(struct notifier_block *nb, unsigned long action,
 	else if (action == BUS_NOTIFY_DEL_DEVICE)
 		notify = vga_arbiter_del_pci_device(pdev);
 
+	vgaarb_dbg(dev, "%s: action = %lu\n", __func__, action);
+
 	if (notify)
 		vga_arbiter_notify_clients();
 	return 0;
@@ -1534,8 +1534,8 @@ static struct miscdevice vga_arb_device = {
 
 static int __init vga_arb_device_init(void)
 {
+	struct pci_dev *pdev = NULL;
 	int rc;
-	struct pci_dev *pdev;
 
 	rc = misc_register(&vga_arb_device);
 	if (rc < 0)
@@ -1545,11 +1545,13 @@ static int __init vga_arb_device_init(void)
 
 	/* We add all PCI devices satisfying VGA class in the arbiter by
 	 * default */
-	pdev = NULL;
-	while ((pdev =
-		pci_get_subsys(PCI_ANY_ID, PCI_ANY_ID, PCI_ANY_ID,
-			       PCI_ANY_ID, pdev)) != NULL)
+	while (1) {
+		pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev);
+		if (!pdev)
+			break;
+
 		vga_arbiter_add_pci_device(pdev);
+	}
 
 	pr_info("loaded\n");
 	return rc;
-- 
2.25.1