On Thu, Sep 25, 2014 at 12:15 PM, Yinghai Lu [off-list ref] wrote:

On Tue, Sep 23, 2014 at 12:01 PM, Liviu Dudau [off-list ref] wrote:

quoted

Before commit 7b5436635800 the pci_host_bridge was created before the root bus.
As that commit has added a needless dependency on the bus for pci_alloc_host_bridge()
the creation order has been changed for no good reason. Revert the order of
creation as we are going to depend on the pci_host_bridge structure to retrieve the
domain number of the root bus.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Acked-by: Grant Likely <redacted>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Tanmay Inamdar <redacted>
---
 drivers/pci/probe.c | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index e3cf8a2..5ff72ec 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c

@@ -515,7 +515,7 @@ static void pci_release_host_bridge_dev(struct device *dev)
        kfree(bridge);
 }

-static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
+static struct pci_host_bridge *pci_alloc_host_bridge(void)
 {
        struct pci_host_bridge *bridge;

@@ -524,7 +524,8 @@ static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
                return NULL;

        INIT_LIST_HEAD(&bridge->windows);
-       bridge->bus = b;
+       bridge->dev.release = pci_release_host_bridge_dev;
+
        return bridge;
 }

@@ -1761,9 +1762,15 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
        char bus_addr[64];
        char *fmt;

+       bridge = pci_alloc_host_bridge();
+       if (!bridge)
+               return NULL;
+
+       bridge->dev.parent = parent;
+
        b = pci_alloc_bus();
        if (!b)
-               return NULL;
+               goto err_out;

        b->sysdata = sysdata;
        b->ops = ops;

@@ -1772,26 +1779,19 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
        if (b2) {
                /* If we already got to this bus through a different bridge, ignore it */
                dev_dbg(&b2->dev, "bus already known\n");
-               goto err_out;
+               goto err_bus_out;
        }

-       bridge = pci_alloc_host_bridge(b);
-       if (!bridge)
-               goto err_out;
-
-       bridge->dev.parent = parent;
-       bridge->dev.release = pci_release_host_bridge_dev;
+       bridge->bus = b;
        dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
        error = pcibios_root_bridge_prepare(bridge);
-       if (error) {
-               kfree(bridge);
+       if (error)
                goto err_out;
-       }

        error = device_register(&bridge->dev);
        if (error) {
                put_device(&bridge->dev);
-               goto err_out;
+               goto err_bus_out;
        }
        b->bridge = get_device(&bridge->dev);
        device_enable_async_suspend(b->bridge);

@@ -1848,8 +1848,10 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 class_dev_reg_err:
        put_device(&bridge->dev);
        device_unregister(&bridge->dev);
-err_out:
+err_bus_out:
        kfree(b);
+err_out:
+       kfree(bridge);
        return NULL;
 }

Hi Bjorn,

Noticed that you put this one into pci/next.

This patch has problem for the class_dev_reg_err path.
as device_unregister(&bridge->dev) will trigger pci_release_host_bridge_dev.
So will have double free for bridge or else.

Please drop this patch from pci/next.

Also looks strange that the patch have long CC list, but just omit me
and Jiang Liu that
touched those code before.

Thanks for noticing that.  I was concerned, but couldn't remember the details.

I dropped this patch and the subsequent ones from pci/host and rebased
my "next" branch.

Sorry I didn't notice you weren't on the CC list.

Bjorn