linux-kernel - [PATCH v6 2/5] PCI: Split out next_ari_fn() from next

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Date:   Tue, 28 Jun 2022 16:30:57 +0200
From:   Niklas Schnelle <schnelle@...ux.ibm.com>
To:     Bjorn Helgaas <bhelgaas@...gle.com>
Cc:     Jan Kiszka <jan.kiszka@...mens.com>,
        Matthew Rosato <mjrosato@...ux.ibm.com>,
        Pierre Morel <pmorel@...ux.ibm.com>,
        linux-s390@...r.kernel.org, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v6 2/5] PCI: Split out next_ari_fn() from next_fn()

In commit b1bd58e448f2 ("PCI: Consolidate "next-function" functions")
the next_fn() function subsumed the traditional and ARI based next
function determination. This got rid of some needlessly complex function
pointer handling but also reduced the separation between these very
different methods of finding the next function. With the next_fn()
cleaned up a bit we can re-introduce this separation by moving out the
ARI handling while sticking with direct function calls.

Signed-off-by: Niklas Schnelle <schnelle@...ux.ibm.com>
---
 drivers/pci/probe.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b05d0ed83a24..2c737dce757e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2579,26 +2579,30 @@ struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn)
 }
 EXPORT_SYMBOL(pci_scan_single_device);
 
-static int next_fn(struct pci_bus *bus, struct pci_dev *dev, int fn)
+static int next_ari_fn(struct pci_bus *bus, struct pci_dev *dev, int fn)
 {
 	int pos;
 	u16 cap = 0;
 	unsigned int next_fn;
 
-	if (pci_ari_enabled(bus)) {
-		if (!dev)
-			return -ENODEV;
-		pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
-		if (!pos)
-			return -ENODEV;
+	if (!dev)
+		return -ENODEV;
+	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI);
+	if (!pos)
+		return -ENODEV;
+
+	pci_read_config_word(dev, pos + PCI_ARI_CAP, &cap);
+	next_fn = PCI_ARI_CAP_NFN(cap);
+	if (next_fn <= fn)
+		return -ENODEV;	/* protect against malformed list */
 
-		pci_read_config_word(dev, pos + PCI_ARI_CAP, &cap);
-		next_fn = PCI_ARI_CAP_NFN(cap);
-		if (next_fn <= fn)
-			return -ENODEV;	/* protect against malformed list */
+	return next_fn;
+}
 
-		return next_fn;
-	}
+static int next_fn(struct pci_bus *bus, struct pci_dev *dev, int fn)
+{
+	if (pci_ari_enabled(bus))
+		return next_ari_fn(bus, dev, fn);
 
 	if (fn >= 7)
 		return -ENODEV;
-- 
2.32.0