[PATCH v4 3/9] powerpc/vas: Add VAS user space API

[Michael Ellerman]

Daniel Axtens <dja at axtens.net> writes:
> Michael Ellerman <mpe at ellerman.id.au> writes:
>> Daniel Axtens <dja at axtens.net> writes:
>>> Haren Myneni <haren at linux.ibm.com> writes:
>>>> diff --git a/arch/powerpc/platforms/powernv/vas-api.c b/arch/powerpc/platforms/powernv/vas-api.c
>>>> new file mode 100644
>>>> index 0000000..7d049af
>>>> --- /dev/null
>>>> +++ b/arch/powerpc/platforms/powernv/vas-api.c
>>>> @@ -0,0 +1,257 @@
>> ...
>>>> +
>>>> +static int coproc_mmap(struct file *fp, struct vm_area_struct *vma)
>>>> +{
>>>> +	struct vas_window *txwin = fp->private_data;
>>>> +	unsigned long pfn;
>>>> +	u64 paste_addr;
>>>> +	pgprot_t prot;
>>>> +	int rc;
>>>> +
>>>> +	if ((vma->vm_end - vma->vm_start) > PAGE_SIZE) {
>>>
>>> I think you said this should be 4096 rather than 64k, regardless of what
>>> PAGE_SIZE you are compiled with?
>>
>> You can't mmap less than a page, a page is PAGE_SIZE bytes.
>>
>> So if that checked for 4K explicitly it would prevent mmap on 64K
>> kernels always, which seems like not what you want?
>
> Ah. My bad. Carry on then :)

Well you were just quoting something from Haren, so I think it's over to
him.

cheers