Re: [PATCH v5 03/25] mm: Make pte_next_pfn() a wrapper around pte_advance_pfn()
From: David Hildenbrand <hidden>
Date: 2024-02-12 12:14:29
Also in:
linux-arm-kernel, linux-mm, lkml
On 02.02.24 09:07, Ryan Roberts wrote:
quoted hunk ↗ jump to hunk
The goal is to be able to advance a PTE by an arbitrary number of PFNs. So introduce a new API that takes a nr param. We are going to remove pte_next_pfn() and replace it with pte_advance_pfn(). As a first step, implement pte_next_pfn() as a wrapper around pte_advance_pfn() so that we can incrementally switch the architectures over. Once all arches are moved over, we will change all the core-mm callers to call pte_advance_pfn() directly and remove the wrapper. Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> --- include/linux/pgtable.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 5e7eaf8f2b97..815d92dcb96b 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h@@ -214,9 +214,15 @@ static inline int pmd_dirty(pmd_t pmd) #ifndef pte_next_pfn +#ifndef pte_advance_pfn +static inline pte_t pte_advance_pfn(pte_t pte, unsigned long nr) +{ + return __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT)); +} +#endif static inline pte_t pte_next_pfn(pte_t pte) { - return __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT)); + return pte_advance_pfn(pte, 1); } #endif
I do wonder if we simply want to leave pte_next_pfn() around? Especially
patch #4, #6 don't really benefit from the change? So are the other
set_ptes() implementations.
That is, only convert all pte_next_pfn()->pte_advance_pfn(), and leave a
pte_next_pfn() macro in place.
Any downsides to that? This patch here would become:
#ifndef pte_advance_pfn
static inline pte_t pte_advance_pfn(pte_t pte, unsigned long nr)
{
return __pte(pte_val(pte) + (nr << PFN_PTE_SHIFT));
}
#endif
#ifndef pte_next_pfn
#define pte_next_pfn(pte) pte_advance_pfn(pte, 1)
#endif
As you convert the three arches, make them define pte_advance_pfn and
udnefine pte_next_pfn. in the end, you can drop the #ifdef around
pte_next_pfn here.
--
Cheers,
David / dhildenb