Re: [PATCH v2, part 1 8/9] PCI: make PCI host bridge/bus creating and destroying logic symmetric

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon 20 May 2013 02:35:31 PM CST, Gu Zheng wrote:

On 05/14/2013 12:08 AM, Jiang Liu wrote:

This patch makes PCI host bridge/bus creating and destroying logic
symmetric by using device_initialize()/device_add()/device_del()/put_device()
pairs as discussed in thread at:
http://comments.gmane.org/gmane.linux.kernel.pci/22073

It also fixes a bug in error recovery path in pci_create_root_bus()
which may kfree() an in-use host bridge object.

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
---
  drivers/pci/probe.c  | 84 +++++++++++++++++++++++-----------------------------
  drivers/pci/remove.c |  3 +-
  2 files changed, 39 insertions(+), 48 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index bc075a3..a2617c2 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -451,7 +451,7 @@ void pci_read_bridge_bases(struct pci_bus *child)
  	}
  }

-static struct pci_bus * pci_alloc_bus(void)
+static struct pci_bus *pci_alloc_bus(struct pci_ops *ops, void *sd, int bus)
  {
  	struct pci_bus *b;

@@ -464,10 +464,32 @@ static struct pci_bus * pci_alloc_bus(void)
  		INIT_LIST_HEAD(&b->resources);
  		b->max_bus_speed = PCI_SPEED_UNKNOWN;
  		b->cur_bus_speed = PCI_SPEED_UNKNOWN;
+		b->sysdata = sd;
+		b->ops = ops;
+		b->number = bus;
+		b->busn_res.start = bus;
+		b->busn_res.end = 0xff;
+		b->busn_res.flags = IORESOURCE_BUS;
+		b->dev.class = &pcibus_class;
+		dev_set_name(&b->dev, "%04x:%02x", pci_domain_nr(b), bus);
+		device_initialize(&b->dev);
  	}
+
  	return b;
  }

+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);
+}
+
  static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
  {
  	struct pci_host_bridge *bridge;
@@ -476,6 +498,10 @@ static struct pci_host_bridge *pci_alloc_host_bridge(struct pci_bus *b)
  	if (bridge) {
  		INIT_LIST_HEAD(&bridge->windows);
  		bridge->bus = b;
+		bridge->dev.release = pci_release_host_bridge_dev;
+		dev_set_name(&bridge->dev, "pci%04x:%02x",
+			     pci_domain_nr(b), b->number);
+		device_initialize(&bridge->dev);
  	}

  	return bridge;
@@ -628,28 +654,13 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
  	/*
  	 * Allocate a new bus, and inherit stuff from the parent..
  	 */
-	child = pci_alloc_bus();
+	child = pci_alloc_bus(parent->ops, parent->sysdata, busnr);
  	if (!child)
  		return NULL;

  	child->parent = parent;
-	child->ops = parent->ops;
-	child->sysdata = parent->sysdata;
  	child->bus_flags = parent->bus_flags;
-
-	/* initialize some portions of the bus device, but don't register it
-	 * now as the parent is not properly set up yet.
-	 */
-	child->dev.class = &pcibus_class;
-	dev_set_name(&child->dev, "%04x:%02x", pci_domain_nr(child), busnr);
-
-	/*
-	 * Set up the primary, secondary and subordinate
-	 * bus numbers.
-	 */
-	child->number = child->busn_res.start = busnr;
  	child->primary = parent->busn_res.start;
-	child->busn_res.end = 0xff;

  	if (!bridge) {
  		child->dev.parent = parent->bridge;
@@ -670,7 +681,7 @@ static struct pci_bus *pci_alloc_child_bus(struct pci_bus *parent,
  	bridge->subordinate = child;

  add_dev:
-	ret = device_register(&child->dev);
+	ret = device_add(&child->dev);
  	WARN_ON(ret < 0);

  	pcibios_add_bus(child);
@@ -1190,18 +1201,6 @@ int pci_cfg_space_size(struct pci_dev *dev)
  	return PCI_CFG_SPACE_SIZE;
  }

-static void pci_release_bus_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_dev *pci_alloc_dev(struct pci_bus *bus)
  {
  	struct pci_dev *dev;
@@ -1688,13 +1687,10 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
  	char bus_addr[64];
  	char *fmt;

-	b = pci_alloc_bus();
+	b = pci_alloc_bus(ops, sysdata, bus);
  	if (!b)
  		return NULL;

-	b->sysdata = sysdata;
-	b->ops = ops;
-	b->number = b->busn_res.start = bus;
  	b2 = pci_find_bus(pci_domain_nr(b), bus);
  	if (b2) {
  		/* If we already got to this bus through a different bridge, ignore it */
@@ -1706,27 +1702,22 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
  	if (!bridge)
  		goto err_out;

-	bridge->dev.parent = parent;
-	bridge->dev.release = pci_release_bus_bridge_dev;
-	dev_set_name(&bridge->dev, "pci%04x:%02x", pci_domain_nr(b), bus);
  	error = pcibios_root_bridge_prepare(bridge);
  	if (error)
  		goto bridge_dev_reg_err;

-	error = device_register(&bridge->dev);
+	bridge->dev.parent = parent;
+	error = device_add(&bridge->dev);
  	if (error)
  		goto bridge_dev_reg_err;
+
  	b->bridge = get_device(&bridge->dev);
  	device_enable_async_suspend(b->bridge);
  	pci_set_bus_of_node(b);
-
  	if (!parent)
  		set_dev_node(b->bridge, pcibus_to_node(b));
-
-	b->dev.class = &pcibus_class;
  	b->dev.parent = b->bridge;
-	dev_set_name(&b->dev, "%04x:%02x", pci_domain_nr(b), bus);
-	error = device_register(&b->dev);
+	error = device_add(&b->dev);
  	if (error)
  		goto class_dev_reg_err;

@@ -1769,12 +1760,11 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
  	return b;

  class_dev_reg_err:
-	put_device(&bridge->dev);
-	device_unregister(&bridge->dev);
+	device_del(&bridge->dev);
  bridge_dev_reg_err:
-	kfree(bridge);
+	put_device(&bridge->dev);
  err_out:
-	kfree(b);
+	put_device(&b->dev);
  	return NULL;
  }

Hi Jiang,
	I think the changes here may lead to memleak, doesn't it?

Best regards,
Gu
Hi Gu Zheng,
I have checked to code again and didn't find the memory leakage issue.
Could you please help to give more hints about the leakage?
Thanks!
Gerry



diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 8fc54b7..b0ce875 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -52,7 +52,8 @@ void pci_remove_bus(struct pci_bus *bus)
  	up_write(&pci_bus_sem);
  	pci_remove_legacy_files(bus);
  	pcibios_remove_bus(bus);
-	device_unregister(&bus->dev);
+	device_del(&bus->dev);
+	put_device(&bus->dev);
  }
  EXPORT_SYMBOL(pci_remove_bus);





--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [DMA Engine]     [Linux Coverity]     [Linux USB]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Greybus]

  Powered by Linux