Patchwork [2/7] PCI: move resources and bus_list releasing to pci_release_dev

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Submitter Yinghai Lu
Date May 14, 2013, 2:28 a.m.
Message ID <1368498506-25857-3-git-send-email-yinghai@kernel.org>
Download mbox | patch
Permalink /patch/243570/
State Superseded
Headers show

Comments

Yinghai Lu - May 14, 2013, 2:28 a.m.
We should not release resource in pci_destroy that is too early
as there could be still other use hold reference.

release them or remove it from bus devices list at last
in pci_release_dev instead.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 drivers/pci/probe.c  |   20 ++++++++++++++++++++
 drivers/pci/remove.c |   19 -------------------
 2 files changed, 20 insertions(+), 19 deletions(-)

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Yijing Wang - May 14, 2013, 3:20 a.m.
On 2013/5/14 10:28, Yinghai Lu wrote:
> We should not release resource in pci_destroy that is too early

Hi Yinghai,
   "too early" means that after pci_stop_dev(), if someone else
hold the device reference, it still care the device resource ? e.g.?

Thanks!
Yijing.

> as there could be still other use hold reference.
> 
> release them or remove it from bus devices list at last
> in pci_release_dev instead.
> 
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> 
> ---
>  drivers/pci/probe.c  |   20 ++++++++++++++++++++
>  drivers/pci/remove.c |   19 -------------------
>  2 files changed, 20 insertions(+), 19 deletions(-)
> 
> Index: linux-2.6/drivers/pci/probe.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/probe.c
> +++ linux-2.6/drivers/pci/probe.c
> @@ -1118,6 +1118,20 @@ static void pci_release_capabilities(str
>  	pci_free_cap_save_buffers(dev);
>  }
>  
> +static void pci_free_resources(struct pci_dev *dev)
> +{
> +	int i;
> +
> +	msi_remove_pci_irq_vectors(dev);
> +
> +	pci_cleanup_rom(dev);
> +	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
> +		struct resource *res = dev->resource + i;
> +		if (res->parent)
> +			release_resource(res);
> +	}
> +}
> +
>  /**
>   * pci_release_dev - free a pci device structure when all users of it are finished.
>   * @dev: device that's been disconnected
> @@ -1130,6 +1144,12 @@ static void pci_release_dev(struct devic
>  	struct pci_dev *pci_dev;
>  
>  	pci_dev = to_pci_dev(dev);
> +
> +	down_write(&pci_bus_sem);
> +	list_del(&pci_dev->bus_list);
> +	up_write(&pci_bus_sem);
> +	pci_free_resources(pci_dev);
> +
>  	pci_release_capabilities(pci_dev);
>  	pci_release_of_node(pci_dev);
>  	kfree(pci_dev);
> Index: linux-2.6/drivers/pci/remove.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/remove.c
> +++ linux-2.6/drivers/pci/remove.c
> @@ -3,20 +3,6 @@
>  #include <linux/pci-aspm.h>
>  #include "pci.h"
>  
> -static void pci_free_resources(struct pci_dev *dev)
> -{
> -	int i;
> -
> - 	msi_remove_pci_irq_vectors(dev);
> -
> -	pci_cleanup_rom(dev);
> -	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
> -		struct resource *res = dev->resource + i;
> -		if (res->parent)
> -			release_resource(res);
> -	}
> -}
> -
>  static void pci_stop_dev(struct pci_dev *dev)
>  {
>  	pci_pme_active(dev, false);
> @@ -34,11 +20,6 @@ static void pci_stop_dev(struct pci_dev
>  
>  static void pci_destroy_dev(struct pci_dev *dev)
>  {
> -	down_write(&pci_bus_sem);
> -	list_del(&dev->bus_list);
> -	up_write(&pci_bus_sem);
> -
> -	pci_free_resources(dev);
>  	put_device(&dev->dev);
>  }
>  
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> .
>
Yinghai Lu - May 14, 2013, 3:56 a.m.
On Mon, May 13, 2013 at 8:20 PM, Yijing Wang <wangyijing@huawei.com> wrote:
> On 2013/5/14 10:28, Yinghai Lu wrote:
>> We should not release resource in pci_destroy that is too early
>
> Hi Yinghai,
>    "too early" means that after pci_stop_dev(), if someone else
> hold the device reference, it still care the device resource ? e.g.?

I don't mean that.

>
>> as there could be still other use hold reference.

purpose is:
move res releasing as late as possible. so pci_stop_and_remove_bus_device
could be called several times for nested removing via sys.

Yinghai
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Yijing Wang - May 14, 2013, 6:02 a.m.
On 2013/5/14 11:56, Yinghai Lu wrote:
> On Mon, May 13, 2013 at 8:20 PM, Yijing Wang <wangyijing@huawei.com> wrote:
>> On 2013/5/14 10:28, Yinghai Lu wrote:
>>> We should not release resource in pci_destroy that is too early
>>
>> Hi Yinghai,
>>    "too early" means that after pci_stop_dev(), if someone else
>> hold the device reference, it still care the device resource ? e.g.?
> 
> I don't mean that.
> 
>>
>>> as there could be still other use hold reference.
> 
> purpose is:
> move res releasing as late as possible. so pci_stop_and_remove_bus_device
> could be called several times for nested removing via sys.

OK, thanks for explanation.

Thanks!
Yijing.

> 
> Yinghai
> 
>

Patch

Index: linux-2.6/drivers/pci/probe.c
===================================================================
--- linux-2.6.orig/drivers/pci/probe.c
+++ linux-2.6/drivers/pci/probe.c
@@ -1118,6 +1118,20 @@  static void pci_release_capabilities(str
 	pci_free_cap_save_buffers(dev);
 }
 
+static void pci_free_resources(struct pci_dev *dev)
+{
+	int i;
+
+	msi_remove_pci_irq_vectors(dev);
+
+	pci_cleanup_rom(dev);
+	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+		struct resource *res = dev->resource + i;
+		if (res->parent)
+			release_resource(res);
+	}
+}
+
 /**
  * pci_release_dev - free a pci device structure when all users of it are finished.
  * @dev: device that's been disconnected
@@ -1130,6 +1144,12 @@  static void pci_release_dev(struct devic
 	struct pci_dev *pci_dev;
 
 	pci_dev = to_pci_dev(dev);
+
+	down_write(&pci_bus_sem);
+	list_del(&pci_dev->bus_list);
+	up_write(&pci_bus_sem);
+	pci_free_resources(pci_dev);
+
 	pci_release_capabilities(pci_dev);
 	pci_release_of_node(pci_dev);
 	kfree(pci_dev);
Index: linux-2.6/drivers/pci/remove.c
===================================================================
--- linux-2.6.orig/drivers/pci/remove.c
+++ linux-2.6/drivers/pci/remove.c
@@ -3,20 +3,6 @@ 
 #include <linux/pci-aspm.h>
 #include "pci.h"
 
-static void pci_free_resources(struct pci_dev *dev)
-{
-	int i;
-
- 	msi_remove_pci_irq_vectors(dev);
-
-	pci_cleanup_rom(dev);
-	for (i = 0; i < PCI_NUM_RESOURCES; i++) {
-		struct resource *res = dev->resource + i;
-		if (res->parent)
-			release_resource(res);
-	}
-}
-
 static void pci_stop_dev(struct pci_dev *dev)
 {
 	pci_pme_active(dev, false);
@@ -34,11 +20,6 @@  static void pci_stop_dev(struct pci_dev
 
 static void pci_destroy_dev(struct pci_dev *dev)
 {
-	down_write(&pci_bus_sem);
-	list_del(&dev->bus_list);
-	up_write(&pci_bus_sem);
-
-	pci_free_resources(dev);
 	put_device(&dev->dev);
 }