From: wangyijing@huawei.com (Yijing Wang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6 10/30] PCI: Introduce pci_host_bridge_list to manage host bridges
Date: Thu, 12 Mar 2015 21:03:12 +0800 [thread overview]
Message-ID: <55018E90.9030301@huawei.com> (raw)
In-Reply-To: <20150312025537.GD10949@google.com>
On 2015/3/12 10:55, Bjorn Helgaas wrote:
> On Mon, Mar 09, 2015 at 10:34:07AM +0800, Yijing Wang wrote:
>> Introduce pci_host_bridge_list to manage pci host
>> bridges in system, so we could detect whether
>> the host in domain:bus is alreay registered.
>> Then we could remove bus alreay exist test in
>> __pci_create_root_bus().
>
> It's a nice idea to move this test into the core. While you're at it, why
> don't you check for any overlap with the bus ranges of existing host
> bridges? For example, if we're trying to create a new host bridge to
> [bus 40-7f], it should conflict with existing bridges to [bus 00-7f]
> as well as to [bus 40-ff]. I think your current patch will detect the
> latter conflict but not the former.
Now pci host bridge may only know its start bus number, like acpi _BBN provided,
but does not limit the end bus number, Eg. two pci roots report _BBN 0x0 and 0x80,
so we have two bus number resource (0, 0xff) and (0x80, 0xff), if we check it strictly,
some pci scan would fail which currently scan success.
>
>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
>> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
>> ---
>> drivers/pci/host-bridge.c | 24 +++++++++++++++++++++++-
>> drivers/pci/probe.c | 8 +-------
>> include/linux/pci.h | 1 +
>> 3 files changed, 25 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
>> index 3bd45e7..0bb08ef 100644
>> --- a/drivers/pci/host-bridge.c
>> +++ b/drivers/pci/host-bridge.c
>> @@ -8,6 +8,9 @@
>>
>> #include "pci.h"
>>
>> +static LIST_HEAD(pci_host_bridge_list);
>> +static DEFINE_MUTEX(phb_mutex);
>
> We don't use the "phb" abbreviation in the PCI core.
OK
>
>> +
>> static void pci_release_host_bridge_dev(struct device *dev)
>> {
>> struct pci_host_bridge *bridge = to_pci_host_bridge(dev);
>> @@ -25,7 +28,7 @@ struct pci_host_bridge *pci_create_host_bridge(
>> int error;
>> int bus = PCI_BUSNUM(db);
>> int domain = PCI_DOMAIN(db);
>> - struct pci_host_bridge *host;
>> + struct pci_host_bridge *host, *temp;
>> struct resource_entry *window, *n;
>>
>> host = kzalloc(sizeof(*host), GFP_KERNEL);
>> @@ -40,6 +43,18 @@ struct pci_host_bridge *pci_create_host_bridge(
>> */
>> pci_host_assign_domain_nr(host);
>>
>> + mutex_lock(&phb_mutex);
>> + list_for_each_entry(temp, &pci_host_bridge_list, list)
>> + if (temp->domain == host->domain
>> + && temp->busnum == host->busnum) {
>> + dev_dbg(&host->dev, "pci host bridge pci%04x:%02x exist\n",
>> + host->domain, host->busnum);
>
> &host->dev hasn't been initialized yet! And the text of the original
> message was better.
Oh, my mistake, good catch.
>
>> + mutex_unlock(&phb_mutex);
>> + kfree(host);
>> + return NULL;
>> + }
>> + mutex_unlock(&phb_mutex);
>
> This is racy. Two CPUs adding a bridge to [bus 00-7f] at about the same
> time can both succeed.
>
Hmm, I need to unlock after I add the new host bridge to the gloal host bridge list, thanks.
> And it needs curly braces around the list_for_each_entry() body.
OK
>
>> +
>> host->dev.parent = parent;
>> INIT_LIST_HEAD(&host->windows);
>> host->dev.release = pci_release_host_bridge_dev;
>> @@ -55,11 +70,18 @@ struct pci_host_bridge *pci_create_host_bridge(
>> resource_list_for_each_entry_safe(window, n, resources)
>> list_move_tail(&window->node, &host->windows);
>>
>> + mutex_lock(&phb_mutex);
>> + list_add_tail(&host->list, &pci_host_bridge_list);
>> + mutex_unlock(&phb_mutex);
>> return host;
>> }
>>
>> void pci_free_host_bridge(struct pci_host_bridge *host)
>> {
>> + mutex_lock(&phb_mutex);
>> + list_del(&host->list);
>> + mutex_unlock(&phb_mutex);
>> +
>> device_unregister(&host->dev);
>> }
>>
>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>> index 27ec612..7238fa3 100644
>> --- a/drivers/pci/probe.c
>> +++ b/drivers/pci/probe.c
>> @@ -1870,7 +1870,7 @@ static struct pci_bus *__pci_create_root_bus(
>> void *sysdata)
>> {
>> int error;
>> - struct pci_bus *b, *b2;
>> + struct pci_bus *b;
>> struct resource_entry *window;
>> struct device *parent;
>> struct resource *res;
>> @@ -1887,12 +1887,6 @@ static struct pci_bus *__pci_create_root_bus(
>> b->ops = ops;
>> b->number = b->busn_res.start = bridge->busnum;
>> pci_bus_assign_domain_nr(b, parent);
>> - b2 = pci_find_bus(pci_domain_nr(b), b->number);
>> - 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;
>> - }
>>
>> bridge->bus = b;
>> b->bridge = get_device(&bridge->dev);
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index 463eaa3..b621f5b 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -406,6 +406,7 @@ struct pci_host_bridge {
>> struct device dev;
>> struct pci_bus *bus; /* root bus */
>> struct list_head windows; /* resource_entry */
>> + struct list_head list;
>> void (*release_fn)(struct pci_host_bridge *);
>> void *release_data;
>> };
>> --
>> 1.7.1
>>
>
> .
>
--
Thanks!
Yijing
next prev parent reply other threads:[~2015-03-12 13:03 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-09 2:33 [PATCH v6 00/30] Refine PCI scan interfaces and make generic pci host bridge Yijing Wang
2015-03-09 2:33 ` [PATCH v6 01/30] PCI: Rip out pci_bus_add_devices() from pci_scan_bus() Yijing Wang
2015-03-09 2:33 ` [PATCH v6 02/30] PCI: Rip out pci_bus_add_devices() from pci_scan_root_bus() Yijing Wang
2015-03-09 2:34 ` [PATCH v6 03/30] PCI: Export busn_resource to drivers/pci Yijing Wang
2015-03-11 22:28 ` Bjorn Helgaas
2015-03-12 11:42 ` Yijing Wang
2015-03-12 19:32 ` Bjorn Helgaas
2015-03-13 1:57 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 04/30] xen/PCI: Don't use deprecated function pci_scan_bus_parented() Yijing Wang
2015-03-11 22:32 ` Bjorn Helgaas
2015-03-12 11:46 ` Yijing Wang
2015-03-12 19:35 ` Bjorn Helgaas
2015-03-13 2:36 ` Yijing Wang
2015-03-13 13:24 ` Bjorn Helgaas
2015-03-13 14:01 ` Konrad Rzeszutek Wilk
2015-03-13 14:26 ` Bjorn Helgaas
2015-03-25 19:23 ` Konrad Rzeszutek Wilk
2015-03-26 1:18 ` Yijing Wang
2015-03-26 7:30 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 05/30] PCI: Remove deprecated pci_scan_bus_parented() Yijing Wang
2015-03-09 2:34 ` [PATCH v6 06/30] PCI: Combine PCI domain and bus number in u32 arg Yijing Wang
2015-03-12 1:29 ` Bjorn Helgaas
2015-03-12 12:14 ` Yijing Wang
2015-03-12 19:49 ` Bjorn Helgaas
2015-03-13 3:19 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 07/30] PCI: Pass PCI domain number combined with root bus number Yijing Wang
2015-03-12 1:34 ` Bjorn Helgaas
2015-03-12 12:20 ` Yijing Wang
2015-03-17 5:15 ` [Xen-devel] " Manish Jaggi
2015-03-17 14:05 ` Ian Campbell
2015-03-09 2:34 ` [PATCH v6 08/30] PCI: Introduce pci_host_assign_domain_nr() to assign domain Yijing Wang
2015-03-12 1:39 ` Bjorn Helgaas
2015-03-12 12:23 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 09/30] PCI: Separate pci_host_bridge creation out of pci_create_root_bus() Yijing Wang
2015-03-12 3:52 ` Bjorn Helgaas
2015-03-12 13:44 ` Yijing Wang
2015-03-21 23:21 ` Suravee Suthikulpanit
2015-03-23 1:08 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 10/30] PCI: Introduce pci_host_bridge_list to manage host bridges Yijing Wang
2015-03-12 2:55 ` Bjorn Helgaas
2015-03-12 13:03 ` Yijing Wang [this message]
2015-03-12 19:56 ` Bjorn Helgaas
2015-03-13 3:28 ` Yijing Wang
2015-03-13 14:33 ` Bjorn Helgaas
2015-03-16 1:28 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 11/30] PCI: Save sysdata in pci_host_bridge drvdata Yijing Wang
2015-03-09 2:34 ` [PATCH v6 12/30] PCI: Introduce pci_host_bridge_ops to support host specific operations Yijing Wang
2015-03-12 3:23 ` Bjorn Helgaas
2015-03-12 13:14 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 13/30] PCI: Introduce new scan function pci_scan_host_bridge() Yijing Wang
2015-03-12 3:25 ` Bjorn Helgaas
2015-03-12 13:15 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 14/30] x86/PCI: Refine pci_acpi_scan_root() with generic pci_host_bridge Yijing Wang
2015-03-09 2:34 ` [PATCH v6 15/30] ia64/PCI: " Yijing Wang
2015-03-09 2:34 ` [PATCH v6 16/30] powerpc/pci: Rename pcibios_root_bridge_prepare() Yijing Wang
2015-03-09 2:34 ` [PATCH v6 17/30] powerpc/pci: Use pci_scan_host_bridge() for simplicity Yijing Wang
2015-03-09 2:34 ` [PATCH v6 18/30] PCI: Remove weak pcibios_root_bridge_prepare() Yijing Wang
2015-03-09 2:34 ` [PATCH v6 19/30] sparc/PCI: Claim bus resources before pci_bus_add_devices() Yijing Wang
2015-03-09 2:34 ` [PATCH v6 20/30] sparc/PCI: Use pci_scan_host_bridge() for simplicity Yijing Wang
2015-03-12 3:30 ` Bjorn Helgaas
2015-03-12 13:17 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 21/30] PCI: Introduce pci_bus_child_max_busnr() Yijing Wang
2015-03-12 3:33 ` Bjorn Helgaas
2015-03-12 13:24 ` Yijing Wang
2015-03-12 3:36 ` Bjorn Helgaas
2015-03-12 13:28 ` Yijing Wang
2015-03-12 20:00 ` Bjorn Helgaas
2015-03-09 2:34 ` [PATCH v6 22/30] parisc/PCI: Use pci_scan_root_bus() for simplicity Yijing Wang
2015-03-09 2:34 ` [PATCH v6 23/30] PCI/mvebu: Use pci_common_init_dev() to simplify code Yijing Wang
2015-03-09 2:34 ` [PATCH v6 24/30] PCI/tegra: Remove redundant tegra_pcie_scan_bus() Yijing Wang
2015-03-09 2:34 ` [PATCH v6 25/30] PCI/designware: Use pci_scan_root_bus() for simplicity Yijing Wang
2015-03-09 2:34 ` [PATCH v6 26/30] PCI/xgene: Use pci_scan_root_bus() instead of pci_create_root_bus() Yijing Wang
2015-03-09 2:34 ` [PATCH v6 27/30] PCI: Rename __pci_create_root_bus() to pci_create_root_bus() Yijing Wang
2015-03-09 2:34 ` [PATCH v6 28/30] PCI: Export find_pci_host_bridge() and rename to pci_find_host_bridge() Yijing Wang
2015-03-12 3:43 ` Bjorn Helgaas
2015-03-12 13:29 ` Yijing Wang
2015-03-09 2:34 ` [PATCH v6 29/30] PCI: Remove platform specific pci_domain_nr() Yijing Wang
2015-03-09 2:34 ` [PATCH v6 30/30] PCI: Remove pci_bus_assign_domain_nr() Yijing Wang
2015-03-12 3:48 ` Bjorn Helgaas
2015-03-12 13:32 ` Yijing Wang
2015-03-12 21:23 ` [PATCH v6 00/30] Refine PCI scan interfaces and make generic pci host bridge Bjorn Helgaas
2015-03-13 3:29 ` Yijing Wang
2015-03-13 11:31 ` Liviu Dudau
2015-03-13 14:48 ` Bjorn Helgaas
2015-03-16 1:31 ` Yijing Wang
2015-03-16 1:48 ` Yijing Wang
2015-03-17 10:55 ` Liviu Dudau
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