Re: [PATCH 0/29] Page Table Interface Explanation

[Paul Cameron Davies <pauld@cse.unsw.EDU.AU>]

Hi Peter

> weird naming, functions are not iterators, if named after what they do
> it should be *_iteration.

Sorry.  I had genuine "iterators" in a previous attempted PTI and never
changed my naming convention.

> But still, I would have expected an iterator based interface; something
> along the lines of:
>
> typedef struct pti_struct {
>  struct mm_struct *mm;
>  pgd_t *pgd;
>  pud_t *pud;
>  pmd_t *pmd;
>  pte_t *pte;
>  spinlock_t *ptl;
>  unsigned long address;
> } pti_t
>
> with accessors like:
>
> #define pti_address(pti) (pti).address
> #define pti_pte(pti) (pti).pte
>
> and methods like:
>
> bool pti_valid(pti_t *pti);
> pti_t pti_lookup(struct mm_struct *mm, unsigned long address);
> pti_t pti_acquire(struct mm_struct *mm, unsigned long address);
> void pti_release(pti_t *pti);
>
> bool pti_next(pti_t *pti);
>
> so that you could write the typical loops like:
>
>  int ret = 0;
>
>  pti_t *pri = pti_lookup(mm, start);
>  do_for_each_pti_range(pti, end) {
>    if (per_pte_op(pti_pte(pti))) {
>      ret = -EFOO;
>      break;
>    }
>  } while_for_each_pti_range(pti, end);
>  pti_release(pti);
>
>  return ret;
>
> where do_for_each_pti_range() and while_for_each_pti_range() look
> something like:
>
> #define do_for_each_pti_range(pti, end) \
>  if (pti_valid(pti) && pti_address(pti) < end) do
>
> #define while_for_each_pti_range(pti, end) \
>  while (pti_next(pti) && pti_valid(pti) && pti_address(pti) < end)
Excellent.

After LCA, I will take what you have given me, and do a version based
around what you would have expected to see.  I hope that you will be 
able to find the time to have a quick look at it :)

Cheers

Paul Davies

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