From: Jim Quinlan <jim2101024@gmail.com>
To: linux-pci@vger.kernel.org,
Nicolas Saenz Julienne <nsaenz@kernel.org>,
Rob Herring <robh@kernel.org>, Mark Brown <broonie@kernel.org>,
bcm-kernel-feedback-list@broadcom.com, jim2101024@gmail.com,
james.quinlan@broadcom.com
Cc: Bjorn Helgaas <bhelgaas@google.com>,
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v7 4/7] PCI: pci_alloc_child_bus() return NULL if ->add_bus() returns -ENOLINK
Date: Wed, 3 Nov 2021 14:49:34 -0400 [thread overview]
Message-ID: <20211103184939.45263-5-jim2101024@gmail.com> (raw)
In-Reply-To: <20211103184939.45263-1-jim2101024@gmail.com>
Currently, if the call to the pci_ops add_bus() method returns an error, a
WARNING and dev_err() occurs. We keep this behavior for all errors except
-ENOLINK; for -ENOLINK we want to skip the WARNING and immediately return
NULL. The argument for this case is that one does not want to continue
enumerating if pcie-link has not been established. The real reason is that
without doing this the pcie-brcmstb.c driver panics when the dev/id is
read, as this controller panics on such accesses rather than returning
0xffffffff.
It appears that there are only a few uses of the pci_ops add_bus() method
in the kernel and none of them currently return -ENOLINK so it should be
safe to do this.
Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
drivers/pci/probe.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index d9fc02a71baa..fdc3f42634b7 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1122,6 +1122,9 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
if (child->ops->add_bus) {
ret = child->ops->add_bus(child);
+ /* Don't return the child if w/o pcie link-up */
+ if (ret == -ENOLINK)
+ return NULL;
if (WARN_ON(ret < 0))
dev_err(&child->dev, "failed to add bus: %d\n", ret);
}
--
2.17.1
next prev parent reply other threads:[~2021-11-03 18:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-03 18:49 [PATCH v7 0/7] PCI: brcmstb: have host-bridge turn on sub-device power Jim Quinlan
2021-11-03 18:49 ` [PATCH v7 1/7] dt-bindings: PCI: Correct brcmstb interrupts, interrupt-map Jim Quinlan
2021-11-03 18:49 ` [PATCH v7 2/7] dt-bindings: PCI: Add bindings for Brcmstb EP voltage regulators Jim Quinlan
2021-11-03 18:49 ` [PATCH v7 3/7] PCI: brcmstb: Split brcm_pcie_setup() into two funcs Jim Quinlan
2021-11-03 18:49 ` Jim Quinlan [this message]
2021-11-03 23:30 ` [PATCH v7 4/7] PCI: pci_alloc_child_bus() return NULL if ->add_bus() returns -ENOLINK Pali Rohár
2021-11-04 13:36 ` Jim Quinlan
2021-11-03 18:49 ` [PATCH v7 5/7] PCI: brcmstb: Add control of subdevice voltage regulators Jim Quinlan
2021-11-03 19:45 ` Mark Brown
2021-11-03 20:25 ` Jim Quinlan
2021-11-03 20:34 ` Jim Quinlan
2021-11-03 21:52 ` Mark Brown
2021-11-03 21:53 ` Jim Quinlan
2021-11-04 15:13 ` Rob Herring
2021-11-03 18:49 ` [PATCH v7 6/7] PCI: brcmstb: Do not turn off regulators if EP can wake up Jim Quinlan
2021-11-03 18:49 ` [PATCH v7 7/7] PCI: brcmstb: Change brcm_phy_stop() to return void Jim Quinlan
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