On Mon, May 4, 2009 at 8:19 PM, Greg KH <greg@xxxxxxxxx> wrote:
> On Mon, May 04, 2009 at 12:47:44PM +0530, arun c wrote:
>> Hi all,
>>
>> I have a dual core system(I am running kernel 2.6.22, 2.6.16, or 2.6.27 ),
>> where I can put a maximum of 8 similar PCI cards.
>>
>> So in my driver I register ('pci_register_driver()') with device ID and
>> vender ID(same for all 8 cards).
>>
>> I need to access a global data from the probe functions. If there are
>> 8 PCI devices detected probe function is called one after another?
>>
>> or is there any chance that they execute in parallel?
>
> Yes, in the future (and in some types of configurations today), it could
> execute in parallel.
>
> Just use a lock to control access to your shared global data structure.
>
> But you might wish to revisit your usage of global data, why can't it be
> a per-device field that is dynamically created for every individual
> device? That would scale much better, right?
I am using a character device interface to talk to my devices.
only one character driver controlling all the PCI devices.
Even if I use per-device fields, I need to store these pointers some
where right?
That means,
lock
global_array[index++] = pointer_to_pci_data_of_just_now_probed_device;
unlock
Other wise I must be calling register_chrdev() in all the device probes and fill
the chrdev private data field. This will end up in too many major no.
for just one
type of device, I think that is not fair.
So I thought I can escape without locks even if I use global data, if the
pci_probe function is atomic!!!!!!!!!!
Regards,
Arun C
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