Re: [PATCH v6 09/30] PCI: Separate pci_host_bridge creation out of pci_create_root_bus()

From: Suravee Suthikulpanit
Date: Sat Mar 21 2015 - 19:22:13 EST




On 3/8/15 21:34, Yijing Wang wrote:
This patch separate pci_host_bridge creation out
of pci_create_root_bus(), and try to make a generic
pci_host_bridge, then we could place generic PCI
infos like domain number in it. Also Ripping out
pci_host_bridge creation from pci_create_root_bus()
make code more better readability. Further more,
we could use the generic pci_host_bridge to hold
host bridge specific operations like
pcibios_root_bridge_prepare(). The changes are
transparent to platform host bridge drivers.

Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/pci/host-bridge.c | 55 ++++++++++++++++++++++
drivers/pci/pci.h | 3 +
drivers/pci/probe.c | 114 ++++++++++++++++++++-------------------------
include/linux/pci.h | 1 +
4 files changed, 109 insertions(+), 64 deletions(-)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index 39b2dbe..3bd45e7 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -8,6 +8,61 @@

#include "pci.h"

+static void pci_release_host_bridge_dev(struct device *dev)
+{
+ struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
+
+ if (bridge->release_fn)
+ bridge->release_fn(bridge);
+
+ pci_free_resource_list(&bridge->windows);
+ kfree(bridge);
+}
+
+struct pci_host_bridge *pci_create_host_bridge(
+ struct device *parent, u32 db, struct list_head *resources)
+{
+ int error;
+ int bus = PCI_BUSNUM(db);
+ int domain = PCI_DOMAIN(db);
+ struct pci_host_bridge *host;
+ struct resource_entry *window, *n;
+
+ host = kzalloc(sizeof(*host), GFP_KERNEL);
+ if (!host)
+ return NULL;
+
+ host->busnum = bus;
+ host->domain = domain;
+ /* If support CONFIG_PCI_DOMAINS_GENERIC, use
+ * pci_host_assign_domain_nr() to assign domain
+ * number instead PCI_DOMAIN(db).
+ */
+ pci_host_assign_domain_nr(host);

At this point, host->dev.parent has not been assigned. However, when calling pci_host_assign_domain_nr(host), it calls pci_assign_domain_nr(host->dev.parent), which uses parent->of_node directly w/o checking if parent is NULL. This ended up causing NULL pointer exception when I do the test.

I think we need to moveo host->dev.parent = parent before calling pci_host_assign_domain_nr(host).

Thanks,

Suravee
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