Subject: Re: [RFC PATCH 02/16] PCI: Use pci_scan_root_bus() instead of pci_scan_bus()

From: Yijing Wang <[email-masked]>
Date: Wed, 19 Nov 2014 09:19:23 +0800

On 2014/11/18 22:28, Liviu Dudau wrote:
> On Mon, Nov 17, 2014 at 10:21:36AM +0000, Yijing Wang wrote:
>> From: Yijing Wang <[email-masked]>
>>
>> Now we could use pci_scan_root_bus() instead of
>> pci_scan_bus(), pass NULL resources means use the default
>> io/mem.
> 
> Actually, I think this patch goes in the wrong direction. You are adding
> two additional parameters that are NULL for every call you replace.
> pci_scan_bus() was actually intended as a "shortcut with defaults" kind
> of call so that you don't have to pass a value for parameters you don't
> care about.
> 
> My suggestion would be to keep the function as is and replace the call
> to pci_create_root_bus() inside with the appropriate sequence.

Hmmm, maybe you are right, provide a simple pci scan interfaces
(which don't care parent and resources) is better than use a complex
one with several NULL arguments. :)

> 
> Best regards,
> Liviu
> 
>>
>> Signed-off-by: Yijing Wang <[email-masked]>
>> ---
>>  arch/alpha/include/asm/pci.h      |    2 +-
>>  arch/alpha/kernel/sys_nautilus.c  |    2 +-
>>  arch/cris/include/asm/pci.h       |    2 +-
>>  arch/ia64/include/asm/pci.h       |    2 +-
>>  arch/m68k/coldfire/pci.c          |    2 +-
>>  arch/mips/include/asm/pci.h       |    2 +-
>>  arch/mn10300/include/asm/pci.h    |    2 +-
>>  arch/sh/include/asm/pci.h         |    2 +-
>>  arch/sparc/include/asm/pci_32.h   |    2 +-
>>  arch/sparc/include/asm/pci_64.h   |    2 +-
>>  arch/sparc/kernel/pcic.c          |    3 ++-
>>  arch/unicore32/kernel/pci.c       |    2 +-
>>  arch/x86/include/asm/pci.h        |    2 +-
>>  arch/x86/pci/amd_bus.c            |    2 +-
>>  arch/xtensa/include/asm/pci.h     |    2 +-
>>  drivers/parisc/dino.c             |    4 ++--
>>  drivers/pci/hotplug/ibmphp_core.c |    2 +-
>>  17 files changed, 19 insertions(+), 18 deletions(-)
>>
>> diff --git a/arch/alpha/include/asm/pci.h b/arch/alpha/include/asm/pci.h
>> index f7f680f..157925a 100644
>> --- a/arch/alpha/include/asm/pci.h
>> +++ b/arch/alpha/include/asm/pci.h
>> @@ -49,7 +49,7 @@ struct pci_controller {
>>  	void *sysdata;
>>  };
>>  
>> -/* Override the logic in pci_scan_bus for skipping already-configured
>> +/* Override the logic in pci_scan_root_bus for skipping already-configured
>>     bus numbers.  */
>>  
>>  #define pcibios_assign_all_busses()	1
>> diff --git a/arch/alpha/kernel/sys_nautilus.c b/arch/alpha/kernel/sys_nautilus.c
>> index 837c0fa..1047ab3 100644
>> --- a/arch/alpha/kernel/sys_nautilus.c
>> +++ b/arch/alpha/kernel/sys_nautilus.c
>> @@ -206,7 +206,7 @@ nautilus_init_pci(void)
>>  	unsigned long memtop = max_low_pfn << PAGE_SHIFT;
>>  
>>  	/* Scan our single hose.  */
>> -	bus = pci_scan_bus(0, alpha_mv.pci_ops, hose);
>> +	bus = pci_scan_root_bus(NULL, 0, alpha_mv.pci_ops, hose, NULL);
>>  	hose->bus = bus;
>>  	pcibios_claim_one_bus(bus);
>>  
>> diff --git a/arch/cris/include/asm/pci.h b/arch/cris/include/asm/pci.h
>> index cc2399c..96b33a6 100644
>> --- a/arch/cris/include/asm/pci.h
>> +++ b/arch/cris/include/asm/pci.h
>> @@ -5,7 +5,7 @@
>>  #ifdef __KERNEL__
>>  #include <linux/mm.h>		/* for struct page */
>>  
>> -/* Can be used to override the logic in pci_scan_bus for skipping
>> +/* Can be used to override the logic in pci_scan_root_bus for skipping
>>     already-configured bus numbers - to be used for buggy BIOSes
>>     or architectures with incomplete PCI setup by the loader */
>>  
>> diff --git a/arch/ia64/include/asm/pci.h b/arch/ia64/include/asm/pci.h
>> index 52af5ed..64b34d6 100644
>> --- a/arch/ia64/include/asm/pci.h
>> +++ b/arch/ia64/include/asm/pci.h
>> @@ -20,7 +20,7 @@ struct pci_vector_struct {
>>  };
>>  
>>  /*
>> - * Can be used to override the logic in pci_scan_bus for skipping already-configured bus
>> + * Can be used to override the logic in pci_scan_root_bus for skipping already-configured bus
>>   * numbers - to be used for buggy BIOSes or architectures with incomplete PCI setup by the
>>   * loader.
>>   */
>> diff --git a/arch/m68k/coldfire/pci.c b/arch/m68k/coldfire/pci.c
>> index df96792..4d242fb 100644
>> --- a/arch/m68k/coldfire/pci.c
>> +++ b/arch/m68k/coldfire/pci.c
>> @@ -312,7 +312,7 @@ static int __init mcf_pci_init(void)
>>  	set_current_state(TASK_UNINTERRUPTIBLE);
>>  	schedule_timeout(msecs_to_jiffies(200));
>>  
>> -	rootbus = pci_scan_bus(0, &mcf_pci_ops, NULL);
>> +	rootbus = pci_scan_root_bus(NULL, 0, &mcf_pci_ops, NULL, NULL);
>>  	rootbus->resource[0] = &mcf_pci_io;
>>  	rootbus->resource[1] = &mcf_pci_mem;
>>  
>> diff --git a/arch/mips/include/asm/pci.h b/arch/mips/include/asm/pci.h
>> index 974b0e3..212030a 100644
>> --- a/arch/mips/include/asm/pci.h
>> +++ b/arch/mips/include/asm/pci.h
>> @@ -60,7 +60,7 @@ extern void register_pci_controller(struct pci_controller *hose);
>>  extern int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin);
>>  
>>  
>> -/* Can be used to override the logic in pci_scan_bus for skipping
>> +/* Can be used to override the logic in pci_scan_root_bus for skipping
>>     already-configured bus numbers - to be used for buggy BIOSes
>>     or architectures with incomplete PCI setup by the loader */
>>  
>> diff --git a/arch/mn10300/include/asm/pci.h b/arch/mn10300/include/asm/pci.h
>> index 5f70af2..6305f14 100644
>> --- a/arch/mn10300/include/asm/pci.h
>> +++ b/arch/mn10300/include/asm/pci.h
>> @@ -33,7 +33,7 @@ do {							\
>>  #define __pcidebug(FMT, BUS, DEVFN, WHERE, ...)	do {} while (0)
>>  #endif
>>  
>> -/* Can be used to override the logic in pci_scan_bus for skipping
>> +/* Can be used to override the logic in pci_scan_root_bus for skipping
>>   * already-configured bus numbers - to be used for buggy BIOSes or
>>   * architectures with incomplete PCI setup by the loader */
>>  
>> diff --git a/arch/sh/include/asm/pci.h b/arch/sh/include/asm/pci.h
>> index 5b45115..69bcb78 100644
>> --- a/arch/sh/include/asm/pci.h
>> +++ b/arch/sh/include/asm/pci.h
>> @@ -3,7 +3,7 @@
>>  
>>  #ifdef __KERNEL__
>>  
>> -/* Can be used to override the logic in pci_scan_bus for skipping
>> +/* Can be used to override the logic in pci_scan_root_bus for skipping
>>     already-configured bus numbers - to be used for buggy BIOSes
>>     or architectures with incomplete PCI setup by the loader */
>>  
>> diff --git a/arch/sparc/include/asm/pci_32.h b/arch/sparc/include/asm/pci_32.h
>> index 53e9b49..4ef6064 100644
>> --- a/arch/sparc/include/asm/pci_32.h
>> +++ b/arch/sparc/include/asm/pci_32.h
>> @@ -5,7 +5,7 @@
>>  
>>  #include <linux/dma-mapping.h>
>>  
>> -/* Can be used to override the logic in pci_scan_bus for skipping
>> +/* Can be used to override the logic in pci_scan_root_bus for skipping
>>   * already-configured bus numbers - to be used for buggy BIOSes
>>   * or architectures with incomplete PCI setup by the loader.
>>   */
>> diff --git a/arch/sparc/include/asm/pci_64.h b/arch/sparc/include/asm/pci_64.h
>> index bd00a62..6e017f9 100644
>> --- a/arch/sparc/include/asm/pci_64.h
>> +++ b/arch/sparc/include/asm/pci_64.h
>> @@ -5,7 +5,7 @@
>>  
>>  #include <linux/dma-mapping.h>
>>  
>> -/* Can be used to override the logic in pci_scan_bus for skipping
>> +/* Can be used to override the logic in pci_scan_root_bus for skipping
>>   * already-configured bus numbers - to be used for buggy BIOSes
>>   * or architectures with incomplete PCI setup by the loader.
>>   */
>> diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c
>> index 6cc78c2..64aafac 100644
>> --- a/arch/sparc/kernel/pcic.c
>> +++ b/arch/sparc/kernel/pcic.c
>> @@ -390,7 +390,8 @@ static void __init pcic_pbm_scan_bus(struct linux_pcic *pcic)
>>  {
>>  	struct linux_pbm_info *pbm = &pcic->pbm;
>>  
>> -	pbm->pci_bus = pci_scan_bus(pbm->pci_first_busno, &pcic_ops, pbm);
>> +	pbm->pci_bus = pci_scan_root_bus(NULL, pbm->pci_first_busno, 
>> +			&pcic_ops, pbm, NULL);
>>  #if 0 /* deadwood transplanted from sparc64 */
>>  	pci_fill_in_pbm_cookies(pbm->pci_bus, pbm, pbm->prom_node);
>>  	pci_record_assignments(pbm, pbm->pci_bus);
>> diff --git a/arch/unicore32/kernel/pci.c b/arch/unicore32/kernel/pci.c
>> index 374a055..be0f261 100644
>> --- a/arch/unicore32/kernel/pci.c
>> +++ b/arch/unicore32/kernel/pci.c
>> @@ -258,7 +258,7 @@ static int __init pci_common_init(void)
>>  
>>  	pci_puv3_preinit();
>>  
>> -	puv3_bus = pci_scan_bus(0, &pci_puv3_ops, NULL);
>> +	puv3_bus = pci_scan_root_bus(NULL, 0, &pci_puv3_ops, NULL, NULL);
>>  
>>  	if (!puv3_bus)
>>  		panic("PCI: unable to scan bus!");
>> diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
>> index 0892ea0..0540ff7 100644
>> --- a/arch/x86/include/asm/pci.h
>> +++ b/arch/x86/include/asm/pci.h
>> @@ -41,7 +41,7 @@ static inline int pci_proc_domain(struct pci_bus *bus)
>>  }
>>  #endif
>>  
>> -/* Can be used to override the logic in pci_scan_bus for skipping
>> +/* Can be used to override the logic in pci_scan_root_bus for skipping
>>     already-configured bus numbers - to be used for buggy BIOSes
>>     or architectures with incomplete PCI setup by the loader */
>>  
>> diff --git a/arch/x86/pci/amd_bus.c b/arch/x86/pci/amd_bus.c
>> index c20d2cc..baf6209 100644
>> --- a/arch/x86/pci/amd_bus.c
>> +++ b/arch/x86/pci/amd_bus.c
>> @@ -52,7 +52,7 @@ static struct pci_root_info __init *find_pci_root_info(int node, int link)
>>  
>>  /**
>>   * early_root_info_init()
>> - * called before pcibios_scan_root and pci_scan_bus
>> + * called before pcibios_scan_root and pci_scan_root_bus
>>   * fills the mp_bus_to_cpumask array based according
>>   * to the LDT Bus Number Registers found in the northbridge.
>>   */
>> diff --git a/arch/xtensa/include/asm/pci.h b/arch/xtensa/include/asm/pci.h
>> index 5d52dc4..377fae9 100644
>> --- a/arch/xtensa/include/asm/pci.h
>> +++ b/arch/xtensa/include/asm/pci.h
>> @@ -13,7 +13,7 @@
>>  
>>  #ifdef __KERNEL__
>>  
>> -/* Can be used to override the logic in pci_scan_bus for skipping
>> +/* Can be used to override the logic in pci_scan_root_bus for skipping
>>   * already-configured bus numbers - to be used for buggy BIOSes
>>   * or architectures with incomplete PCI setup by the loader
>>   */
>> diff --git a/drivers/parisc/dino.c b/drivers/parisc/dino.c
>> index a0580af..67c31bd 100644
>> --- a/drivers/parisc/dino.c
>> +++ b/drivers/parisc/dino.c
>> @@ -74,7 +74,7 @@
>>  ** assigned a PCI bus number based on "when" it's discovered.
>>  **
>>  ** The "secondary" bus number is set to this before calling
>> -** pci_scan_bus(). If any PPB's are present, the scan will
>> +** pci_scan_root_bus(). If any PPB's are present, the scan will
>>  ** discover them and update the "secondary" and "subordinate"
>>  ** fields in Dino's pci_bus structure.
>>  **
>> @@ -787,7 +787,7 @@ static int __init dino_common_init(struct parisc_device *dev,
>>  
>>  	pcibios_register_hba(&dino_dev->hba);
>>  
>> -	pci_bios = &dino_bios_ops;   /* used by pci_scan_bus() */
>> +	pci_bios = &dino_bios_ops;   
>>  	pci_port = &dino_port_ops;
>>  
>>  	/*
>> diff --git a/drivers/pci/hotplug/ibmphp_core.c b/drivers/pci/hotplug/ibmphp_core.c
>> index 3efaf4c..b486432 100644
>> --- a/drivers/pci/hotplug/ibmphp_core.c
>> +++ b/drivers/pci/hotplug/ibmphp_core.c
>> @@ -767,7 +767,7 @@ static u8 bus_structure_fixup(u8 busno)
>>  					(l != 0x0000) && (l != 0xffff)) {
>>  			debug("%s - Inside bus_structure_fixup()\n",
>>  							__func__);
>> -			pci_scan_bus(busno, ibmphp_pci_bus->ops, NULL);
>> +			pci_scan_root_bus(NULL, busno, ibmphp_pci_bus->ops, NULL, NULL);
>>  			break;
>>  		}
>>  	}
>> -- 
>> 1.7.1
>>
>> --
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>>
> 

-- 
Thanks!
Yijing