Patchwork [RFC,v1,1/6] PCI: change PCI device management logic to better follow device model

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Submitter Jiang Liu
Date June 4, 2012, 5:16 a.m.
Message ID <1338787022-400-1-git-send-email-jiang.liu@huawei.com>
Download mbox | patch
Permalink /patch/162619/
State Superseded
Headers show

Comments

Jiang Liu - June 4, 2012, 5:16 a.m.
From: Jiang Liu <liuj97@gmail.com>

According to device model documentation, the way to add/remove device
object should be symmetric.

/**
 * device_del - delete device from system.
 * @dev: device.
 *
 * This is the first part of the device unregistration
 * sequence. This removes the device from the lists we control
 * from here, has it removed from the other driver model
 * subsystems it was added to in device_add(), and removes it
 * from the kobject hierarchy.
 *
 * NOTE: this should be called manually _iff_ device_add() was
 * also called manually.
 */

The rule here is to either use
1) device_register()/device_unregister()
or
2) device_initialize()/device_add()/device_del()/put_device().

So change PCI core to follow the rule and get rid of the redundant
pci_dev_get()/pci_dev_put() pair.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
 drivers/pci/probe.c  |    1 -
 drivers/pci/remove.c |    4 ++--
 2 files changed, 2 insertions(+), 3 deletions(-)
Taku Izumi - June 14, 2012, 9:18 a.m.
Hi Jiang,

   Looks good for me.

 Best regards,
 Taku Izumi

On Mon, 04 Jun 2012 13:16:57 +0800
Jiang Liu <jiang.liu@huawei.com> wrote:

> From: Jiang Liu <liuj97@gmail.com>
> 
> According to device model documentation, the way to add/remove device
> object should be symmetric.
> 
> /**
>  * device_del - delete device from system.
>  * @dev: device.
>  *
>  * This is the first part of the device unregistration
>  * sequence. This removes the device from the lists we control
>  * from here, has it removed from the other driver model
>  * subsystems it was added to in device_add(), and removes it
>  * from the kobject hierarchy.
>  *
>  * NOTE: this should be called manually _iff_ device_add() was
>  * also called manually.
>  */
> 
> The rule here is to either use
> 1) device_register()/device_unregister()
> or
> 2) device_initialize()/device_add()/device_del()/put_device().
> 
> So change PCI core to follow the rule and get rid of the redundant
> pci_dev_get()/pci_dev_put() pair.
> 
> Signed-off-by: Jiang Liu <liuj97@gmail.com>
> ---
>  drivers/pci/probe.c  |    1 -
>  drivers/pci/remove.c |    4 ++--
>  2 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 0840409..dacca26 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1294,7 +1294,6 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
>  {
>  	device_initialize(&dev->dev);
>  	dev->dev.release = pci_release_dev;
> -	pci_dev_get(dev);
>  
>  	dev->dev.dma_mask = &dev->dma_mask;
>  	dev->dev.dma_parms = &dev->dma_parms;
> diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
> index 04a4861..6c07bc5 100644
> --- a/drivers/pci/remove.c
> +++ b/drivers/pci/remove.c
> @@ -22,7 +22,7 @@ static void pci_stop_dev(struct pci_dev *dev)
>  	if (dev->is_added) {
>  		pci_proc_detach_device(dev);
>  		pci_remove_sysfs_dev_files(dev);
> -		device_unregister(&dev->dev);
> +		device_del(&dev->dev);
>  		dev->is_added = 0;
>  	}
>  
> @@ -40,7 +40,7 @@ static void pci_destroy_dev(struct pci_dev *dev)
>  	up_write(&pci_bus_sem);
>  
>  	pci_free_resources(dev);
> -	pci_dev_put(dev);
> +	put_device(&dev->dev);
>  }
>  
>  /**
> -- 
> 1.7.1
> 
> 
> 

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Bjorn Helgaas - Aug. 15, 2012, 8:21 p.m.
On Sun, Jun 3, 2012 at 11:16 PM, Jiang Liu <jiang.liu@huawei.com> wrote:
> From: Jiang Liu <liuj97@gmail.com>
>
> According to device model documentation, the way to add/remove device
> object should be symmetric.

I think this 6-patch series has been folded into your "[RFC PATCH v1
00/22] introduce PCI bus lock to serialize PCI hotplug operations"
series posted August 8, right?

I'll ignore these 6 patches on that assumption, so let me know if otherwise.

> /**
>  * device_del - delete device from system.
>  * @dev: device.
>  *
>  * This is the first part of the device unregistration
>  * sequence. This removes the device from the lists we control
>  * from here, has it removed from the other driver model
>  * subsystems it was added to in device_add(), and removes it
>  * from the kobject hierarchy.
>  *
>  * NOTE: this should be called manually _iff_ device_add() was
>  * also called manually.
>  */
>
> The rule here is to either use
> 1) device_register()/device_unregister()
> or
> 2) device_initialize()/device_add()/device_del()/put_device().
>
> So change PCI core to follow the rule and get rid of the redundant
> pci_dev_get()/pci_dev_put() pair.
>
> Signed-off-by: Jiang Liu <liuj97@gmail.com>
> ---
>  drivers/pci/probe.c  |    1 -
>  drivers/pci/remove.c |    4 ++--
>  2 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 0840409..dacca26 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1294,7 +1294,6 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
>  {
>         device_initialize(&dev->dev);
>         dev->dev.release = pci_release_dev;
> -       pci_dev_get(dev);
>
>         dev->dev.dma_mask = &dev->dma_mask;
>         dev->dev.dma_parms = &dev->dma_parms;
> diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
> index 04a4861..6c07bc5 100644
> --- a/drivers/pci/remove.c
> +++ b/drivers/pci/remove.c
> @@ -22,7 +22,7 @@ static void pci_stop_dev(struct pci_dev *dev)
>         if (dev->is_added) {
>                 pci_proc_detach_device(dev);
>                 pci_remove_sysfs_dev_files(dev);
> -               device_unregister(&dev->dev);
> +               device_del(&dev->dev);
>                 dev->is_added = 0;
>         }
>
> @@ -40,7 +40,7 @@ static void pci_destroy_dev(struct pci_dev *dev)
>         up_write(&pci_bus_sem);
>
>         pci_free_resources(dev);
> -       pci_dev_put(dev);
> +       put_device(&dev->dev);
>  }
>
>  /**
> --
> 1.7.1
>
>
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Patch

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 0840409..dacca26 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1294,7 +1294,6 @@  void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 {
 	device_initialize(&dev->dev);
 	dev->dev.release = pci_release_dev;
-	pci_dev_get(dev);
 
 	dev->dev.dma_mask = &dev->dma_mask;
 	dev->dev.dma_parms = &dev->dma_parms;
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 04a4861..6c07bc5 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -22,7 +22,7 @@  static void pci_stop_dev(struct pci_dev *dev)
 	if (dev->is_added) {
 		pci_proc_detach_device(dev);
 		pci_remove_sysfs_dev_files(dev);
-		device_unregister(&dev->dev);
+		device_del(&dev->dev);
 		dev->is_added = 0;
 	}
 
@@ -40,7 +40,7 @@  static void pci_destroy_dev(struct pci_dev *dev)
 	up_write(&pci_bus_sem);
 
 	pci_free_resources(dev);
-	pci_dev_put(dev);
+	put_device(&dev->dev);
 }
 
 /**