linux-kernel - [PATCH 19/25] PCI: Extend enable to check for any optional resource

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Message-Id: <20241216175632.4175-20-ilpo.jarvinen@linux.intel.com>
Date: Mon, 16 Dec 2024 19:56:26 +0200
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
	linux-pci@...r.kernel.org,
	Michał Winiarski <michal.winiarski@...el.com>,
	Igor Mammedov <imammedo@...hat.com>,
	linux-kernel@...r.kernel.org
Cc: Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [PATCH 19/25] PCI: Extend enable to check for any optional resource

pci_enable_resources() checks if device's io and mem resources are all
assigned and disallows enable if any resource failed to assign (*) but
makes an exception for the case of disabled extension ROM. There are
other optional resources, however.

Add pci_resource_is_optional() and use it instead of
pci_resource_is_disabled_rom() to cover also IOV resources that are
also optional as per pbus_size_mem().

As there will be more users of pci_resource_is_optional() inside
setup-bus.c in changes coming up after this one, the function is
placed there.

(*) In practice, resource fitting code calls reset_resource() for any
resource it fails to assign which clears resource's ->flags causing
pci_enable_resources() to never detect failed resource assignments.
This seems undesirable internal logic inconsistency, effectively
reset_resource() prevents pci_enable_resources() from functioning as
intended. This is one step of many that will be needed towards removing
reset_resource().

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
---
 drivers/pci/pci.h       |  1 +
 drivers/pci/setup-bus.c | 12 ++++++++++++
 drivers/pci/setup-res.c |  3 +--
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 0b722d158b6a..efdb9af8e256 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -329,6 +329,7 @@ void pci_walk_bus_locked(struct pci_bus *top,
 			 void *userdata);
 
 const char *pci_resource_name(struct pci_dev *dev, unsigned int i);
+bool pci_resource_is_optional(const struct pci_dev *dev, int resno);
 
 /**
  * pci_resource_num - Reverse lookup resource number from device resources
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index d30e8a5a0311..a4e40916e2fc 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -206,6 +206,18 @@ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
 	}
 }
 
+bool pci_resource_is_optional(const struct pci_dev *dev, int resno)
+{
+	const struct resource *res = pci_resource_n(dev, resno);
+
+	if (pci_resource_is_iov(resno))
+		return true;
+	if (resno == PCI_ROM_RESOURCE && !(res->flags & IORESOURCE_ROM_ENABLE))
+		return true;
+
+	return false;
+}
+
 static inline void reset_resource(struct resource *res)
 {
 	res->start = 0;
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index a862b5d769dc..041c881c3c9c 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -494,8 +494,7 @@ int pci_enable_resources(struct pci_dev *dev, int mask)
 
 		if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
 			continue;
-		if ((i == PCI_ROM_RESOURCE) &&
-				(!(r->flags & IORESOURCE_ROM_ENABLE)))
+		if (pci_resource_is_optional(dev, i))
 			continue;
 
 		if (r->flags & IORESOURCE_UNSET) {
-- 
2.39.5