Re: [PATCH kernel 2/5] powerpc/eeh: Reduce to one the number of places where edev is allocated

[Andrew Donnellan <andrew.donnellan@au1.ibm.com>]

On 23/08/17 20:18, Alexey Kardashevskiy wrote:
> arch/powerpc/kernel/eeh_dev.c:57 is the only legit place where edev
> is allocated; other 2 places allocate it on stack and in the heap for
> a very short period of time to use eeh_pe_get() as takes edev.
> 
> This changes eeh_pe_get() to receive required parameters explicitly.
> 
> This removes unnecessary temporary allocation of edev.
> 
> This uses the "pe_no" name instead of the "pe_config_addr" name as
> it actually is a PE number and not a config space address as it seemed.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>

> ---
>   arch/powerpc/include/asm/eeh.h               |  3 ++-
>   arch/powerpc/kernel/eeh_pe.c                 | 32 ++++++++++++++++++----------
>   arch/powerpc/platforms/powernv/eeh-powernv.c | 15 ++-----------
>   3 files changed, 25 insertions(+), 25 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
> index 8e37b71674f4..26a6a43f8799 100644
> --- a/arch/powerpc/include/asm/eeh.h
> +++ b/arch/powerpc/include/asm/eeh.h
> @@ -262,7 +262,8 @@ typedef void *(*eeh_traverse_func)(void *data, void *flag);
>   void eeh_set_pe_aux_size(int size);
>   int eeh_phb_pe_create(struct pci_controller *phb);
>   struct eeh_pe *eeh_phb_pe_get(struct pci_controller *phb);
> -struct eeh_pe *eeh_pe_get(struct eeh_dev *edev);
> +struct eeh_pe *eeh_pe_get(struct pci_controller *phb,
> +			  int pe_no, int config_addr);
>   int eeh_add_to_parent_pe(struct eeh_dev *edev);
>   int eeh_rmv_from_parent_pe(struct eeh_dev *edev);
>   void eeh_pe_update_time_stamp(struct eeh_pe *pe);
> diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
> index cc4b206f77e4..84d79f3da7d6 100644
> --- a/arch/powerpc/kernel/eeh_pe.c
> +++ b/arch/powerpc/kernel/eeh_pe.c
> @@ -230,10 +230,15 @@ void *eeh_pe_dev_traverse(struct eeh_pe *root,
>    * Bus/Device/Function number. The extra data referred by flag
>    * indicates which type of address should be used.
>    */
> +struct eeh_pe_get_flag {
> +	int pe_no;
> +	int config_addr;
> +};
> +
>   static void *__eeh_pe_get(void *data, void *flag)
>   {
>   	struct eeh_pe *pe = (struct eeh_pe *)data;
> -	struct eeh_dev *edev = (struct eeh_dev *)flag;
> +	struct eeh_pe_get_flag *tmp = (struct eeh_pe_get_flag *) flag;
>   
>   	/* Unexpected PHB PE */
>   	if (pe->type & EEH_PE_PHB)
> @@ -244,17 +249,17 @@ static void *__eeh_pe_get(void *data, void *flag)
>   	 * have non-zero PE address
>   	 */
>   	if (eeh_has_flag(EEH_VALID_PE_ZERO)) {
> -		if (edev->pe_config_addr == pe->addr)
> +		if (tmp->pe_no == pe->addr)
>   			return pe;
>   	} else {
> -		if (edev->pe_config_addr &&
> -		    (edev->pe_config_addr == pe->addr))
> +		if (tmp->pe_no &&
> +		    (tmp->pe_no == pe->addr))
>   			return pe;
>   	}
>   
>   	/* Try BDF address */
> -	if (edev->config_addr &&
> -	   (edev->config_addr == pe->config_addr))
> +	if (tmp->config_addr &&
> +	   (tmp->config_addr == pe->config_addr))
>   		return pe;
>   
>   	return NULL;
> @@ -262,7 +267,9 @@ static void *__eeh_pe_get(void *data, void *flag)
>   
>   /**
>    * eeh_pe_get - Search PE based on the given address
> - * @edev: EEH device
> + * @phb: PCI controller
> + * @pe_no: PE number
> + * @config_addr: Config address
>    *
>    * Search the corresponding PE based on the specified address which
>    * is included in the eeh device. The function is used to check if
> @@ -271,12 +278,14 @@ static void *__eeh_pe_get(void *data, void *flag)
>    * which is composed of PCI bus/device/function number, or unified
>    * PE address.
>    */
> -struct eeh_pe *eeh_pe_get(struct eeh_dev *edev)
> +struct eeh_pe *eeh_pe_get(struct pci_controller *phb,
> +		int pe_no, int config_addr)
>   {
> -	struct eeh_pe *root = eeh_phb_pe_get(edev->phb);
> +	struct eeh_pe *root = eeh_phb_pe_get(phb);
> +	struct eeh_pe_get_flag tmp = { pe_no, config_addr };
>   	struct eeh_pe *pe;
>   
> -	pe = eeh_pe_traverse(root, __eeh_pe_get, edev);
> +	pe = eeh_pe_traverse(root, __eeh_pe_get, &tmp);
>   
>   	return pe;
>   }
> @@ -344,7 +353,8 @@ int eeh_add_to_parent_pe(struct eeh_dev *edev)
>   	 * PE should be composed of PCI bus and its subordinate
>   	 * components.
>   	 */
> -	pe = eeh_pe_get(edev);
> +	pe = eeh_pe_get(edev->pdn->phb, edev->pe_config_addr,
> +			edev->config_addr);
>   	if (pe && !(pe->type & EEH_PE_INVALID)) {
>   		/* Mark the PE as type of PCI bus */
>   		pe->type = EEH_PE_BUS;
> diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
> index 3f48f6df1cf3..ac8c01cd251c 100644
> --- a/arch/powerpc/platforms/powernv/eeh-powernv.c
> +++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
> @@ -113,7 +113,6 @@ static ssize_t pnv_eeh_ei_write(struct file *filp,
>   				size_t count, loff_t *ppos)
>   {
>   	struct pci_controller *hose = filp->private_data;
> -	struct eeh_dev *edev;
>   	struct eeh_pe *pe;
>   	int pe_no, type, func;
>   	unsigned long addr, mask;
> @@ -135,13 +134,7 @@ static ssize_t pnv_eeh_ei_write(struct file *filp,
>   		return -EINVAL;
>   
>   	/* Retrieve PE */
> -	edev = kzalloc(sizeof(*edev), GFP_KERNEL);
> -	if (!edev)
> -		return -ENOMEM;
> -	edev->phb = hose;
> -	edev->pe_config_addr = pe_no;
> -	pe = eeh_pe_get(edev);
> -	kfree(edev);
> +	pe = eeh_pe_get(hose, pe_no, 0);
>   	if (!pe)
>   		return -ENODEV;
>   
> @@ -1381,7 +1374,6 @@ static int pnv_eeh_get_pe(struct pci_controller *hose,
>   	struct pnv_phb *phb = hose->private_data;
>   	struct pnv_ioda_pe *pnv_pe;
>   	struct eeh_pe *dev_pe;
> -	struct eeh_dev edev;
>   
>   	/*
>   	 * If PHB supports compound PE, to fetch
> @@ -1397,10 +1389,7 @@ static int pnv_eeh_get_pe(struct pci_controller *hose,
>   	}
>   
>   	/* Find the PE according to PE# */
> -	memset(&edev, 0, sizeof(struct eeh_dev));
> -	edev.phb = hose;
> -	edev.pe_config_addr = pe_no;
> -	dev_pe = eeh_pe_get(&edev);
> +	dev_pe = eeh_pe_get(hose, pe_no, 0);
>   	if (!dev_pe)
>   		return -EEXIST;
>   
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan@au1.ibm.com  IBM Australia Limited