Re: [Patch v5 1/2] PCI: hv: Decouple the func definition in hv_dr_state from VSP message

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Tue, Feb 25, 2020 at 09:06:07PM -0800, longli@linuxonhyperv.com wrote:
> From: Long Li <longli@microsoft.com>
> 
> hv_dr_state is used to find present PCI devices on the bus. The structure
> reuses struct pci_function_description from VSP message to describe a
> device.
> 
> To prepare support for pci_function_description v2, decouple this
> dependence in hv_dr_state so it can work with both v1 and v2 VSP messages.
> 
> There is no functionality change.
> 
> Signed-off-by: Long Li <longli@microsoft.com>
> Reviewed-by: Michael Kelley <mikelley@microsoft.com>
> ---
> Changes
> v2: Changed some spaces to tabs, changed failure code to -ENOMEM
> v3: Revised comment for function hv_pci_devices_present(), reformatted patch title
> v4: Fixed spelling
> v5: Rebased to current tree
> 
>  drivers/pci/controller/pci-hyperv.c | 100 +++++++++++++++++++++++++-----------
>  1 file changed, 70 insertions(+), 30 deletions(-)

Applied the series to pci/hv for v5.7.

Thanks,
Lorenzo

> 
> index 15011a3..dea197f 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -505,10 +505,24 @@ struct hv_dr_work {
>  	struct hv_pcibus_device *bus;
>  };
>  
> +struct hv_pcidev_description {
> +	u16	v_id;	/* vendor ID */
> +	u16	d_id;	/* device ID */
> +	u8	rev;
> +	u8	prog_intf;
> +	u8	subclass;
> +	u8	base_class;
> +	u32	subsystem_id;
> +	union	win_slot_encoding win_slot;
> +	u32	ser;	/* serial number */
> +	u32	flags;
> +	u16	virtual_numa_node;
> +};
> +
>  struct hv_dr_state {
>  	struct list_head list_entry;
>  	u32 device_count;
> -	struct pci_function_description func[0];
> +	struct hv_pcidev_description func[0];
>  };
>  
>  enum hv_pcichild_state {
> @@ -525,7 +539,7 @@ struct hv_pci_dev {
>  	refcount_t refs;
>  	enum hv_pcichild_state state;
>  	struct pci_slot *pci_slot;
> -	struct pci_function_description desc;
> +	struct hv_pcidev_description desc;
>  	bool reported_missing;
>  	struct hv_pcibus_device *hbus;
>  	struct work_struct wrk;
> @@ -1877,7 +1891,7 @@ static void q_resource_requirements(void *context, struct pci_response *resp,
>   * Return: Pointer to the new tracking struct
>   */
>  static struct hv_pci_dev *new_pcichild_device(struct hv_pcibus_device *hbus,
> -		struct pci_function_description *desc)
> +		struct hv_pcidev_description *desc)
>  {
>  	struct hv_pci_dev *hpdev;
>  	struct pci_child_message *res_req;
> @@ -1988,7 +2002,7 @@ static void pci_devices_present_work(struct work_struct *work)
>  {
>  	u32 child_no;
>  	bool found;
> -	struct pci_function_description *new_desc;
> +	struct hv_pcidev_description *new_desc;
>  	struct hv_pci_dev *hpdev;
>  	struct hv_pcibus_device *hbus;
>  	struct list_head removed;
> @@ -2107,17 +2121,15 @@ static void pci_devices_present_work(struct work_struct *work)
>  }
>  
>  /**
> - * hv_pci_devices_present() - Handles list of new children
> + * hv_pci_start_relations_work() - Queue work to start device discovery
>   * @hbus:	Root PCI bus, as understood by this driver
> - * @relations:	Packet from host listing children
> + * @dr:		The list of children returned from host
>   *
> - * This function is invoked whenever a new list of devices for
> - * this bus appears.
> + * Return:  0 on success, -errno on failure
>   */
> -static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
> -				   struct pci_bus_relations *relations)
> +static int hv_pci_start_relations_work(struct hv_pcibus_device *hbus,
> +				       struct hv_dr_state *dr)
>  {
> -	struct hv_dr_state *dr;
>  	struct hv_dr_work *dr_wrk;
>  	unsigned long flags;
>  	bool pending_dr;
> @@ -2125,29 +2137,15 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
>  	if (hbus->state == hv_pcibus_removing) {
>  		dev_info(&hbus->hdev->device,
>  			 "PCI VMBus BUS_RELATIONS: ignored\n");
> -		return;
> +		return -ENOENT;
>  	}
>  
>  	dr_wrk = kzalloc(sizeof(*dr_wrk), GFP_NOWAIT);
>  	if (!dr_wrk)
> -		return;
> -
> -	dr = kzalloc(offsetof(struct hv_dr_state, func) +
> -		     (sizeof(struct pci_function_description) *
> -		      (relations->device_count)), GFP_NOWAIT);
> -	if (!dr)  {
> -		kfree(dr_wrk);
> -		return;
> -	}
> +		return -ENOMEM;
>  
>  	INIT_WORK(&dr_wrk->wrk, pci_devices_present_work);
>  	dr_wrk->bus = hbus;
> -	dr->device_count = relations->device_count;
> -	if (dr->device_count != 0) {
> -		memcpy(dr->func, relations->func,
> -		       sizeof(struct pci_function_description) *
> -		       dr->device_count);
> -	}
>  
>  	spin_lock_irqsave(&hbus->device_list_lock, flags);
>  	/*
> @@ -2165,6 +2163,47 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
>  		get_hvpcibus(hbus);
>  		queue_work(hbus->wq, &dr_wrk->wrk);
>  	}
> +
> +	return 0;
> +}
> +
> +/**
> + * hv_pci_devices_present() - Handle list of new children
> + * @hbus:      Root PCI bus, as understood by this driver
> + * @relations: Packet from host listing children
> + *
> + * Process a new list of devices on the bus. The list of devices is
> + * discovered by VSP and sent to us via VSP message PCI_BUS_RELATIONS,
> + * whenever a new list of devices for this bus appears.
> + */
> +static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
> +				   struct pci_bus_relations *relations)
> +{
> +	struct hv_dr_state *dr;
> +	int i;
> +
> +	dr = kzalloc(offsetof(struct hv_dr_state, func) +
> +		     (sizeof(struct hv_pcidev_description) *
> +		      (relations->device_count)), GFP_NOWAIT);
> +
> +	if (!dr)
> +		return;
> +
> +	dr->device_count = relations->device_count;
> +	for (i = 0; i < dr->device_count; i++) {
> +		dr->func[i].v_id = relations->func[i].v_id;
> +		dr->func[i].d_id = relations->func[i].d_id;
> +		dr->func[i].rev = relations->func[i].rev;
> +		dr->func[i].prog_intf = relations->func[i].prog_intf;
> +		dr->func[i].subclass = relations->func[i].subclass;
> +		dr->func[i].base_class = relations->func[i].base_class;
> +		dr->func[i].subsystem_id = relations->func[i].subsystem_id;
> +		dr->func[i].win_slot = relations->func[i].win_slot;
> +		dr->func[i].ser = relations->func[i].ser;
> +	}
> +
> +	if (hv_pci_start_relations_work(hbus, dr))
> +		kfree(dr);
>  }
>  
>  /**
> @@ -3069,7 +3108,7 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool hibernating)
>  		struct pci_packet teardown_packet;
>  		u8 buffer[sizeof(struct pci_message)];
>  	} pkt;
> -	struct pci_bus_relations relations;
> +	struct hv_dr_state *dr;
>  	struct hv_pci_compl comp_pkt;
>  	int ret;
>  
> @@ -3082,8 +3121,9 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool hibernating)
>  
>  	if (!hibernating) {
>  		/* Delete any children which might still exist. */
> -		memset(&relations, 0, sizeof(relations));
> -		hv_pci_devices_present(hbus, &relations);
> +		dr = kzalloc(sizeof(*dr), GFP_KERNEL);
> +		if (dr && hv_pci_start_relations_work(hbus, dr))
> +			kfree(dr);
>  	}
>  
>  	ret = hv_send_resources_released(hdev);
> -- 
> 1.8.3.1
>