Received-SPF: pass (google.com: domain of linux-kernel+bounces-135787-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Date: Mon, 8 Apr 2024 18:55:34 +0100
From: Matthew Wilcox <willy@infradead.org>
To: Vishal Moola <vishal.moola@gmail.com>
Cc: Muchun Song <muchun.song@linux.dev>, linux-kernel@vger.kernel.org,
	akpm@linux-foundation.org, linux-mm@kvack.org
Subject: Re: [PATCH v2 3/3] hugetlb: Convert hugetlb_wp() to use struct
 vm_fault
Message-ID: <ZhQvlpOETGxXO_MG@casper.infradead.org>
References: <20240401202651.31440-1-vishal.moola@gmail.com>
 <20240401202651.31440-4-vishal.moola@gmail.com>
 <7d001108-157d-4139-bfa9-5b4102166f17@linux.dev>
 <ZhQtoFNZBNwBCeXn@fedora>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ZhQtoFNZBNwBCeXn@fedora>

On Mon, Apr 08, 2024 at 10:47:12AM -0700, Vishal Moola wrote:
> -static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
> -		       struct folio *pagecache_folio,
> +static vm_fault_t hugetlb_wp(struct folio *pagecache_folio,
>  		       struct vm_fault *vmf)
>  {
> +	struct vm_area_struct *vma = vmf->vma;
> +	struct mm_struct *mm = vma->vm_mm;

I think 'vmf' should be the first parameter, not the second.
Compare:

static vm_fault_t do_page_mkwrite(struct vm_fault *vmf, struct folio *folio)
static inline void wp_page_reuse(struct vm_fault *vmf, struct folio *folio)
static vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf, struct folio *folio)
static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio)
vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
void set_pte_range(struct vm_fault *vmf, struct folio *folio,
                struct page *page, unsigned int nr, unsigned long addr)
int numa_migrate_prep(struct folio *folio, struct vm_fault *vmf,
                      unsigned long addr, int page_nid, int *flags)
static void numa_rebuild_single_mapping(struct vm_fault *vmf, struct vm_area_struct *vma,
                                        unsigned long fault_addr, pte_t *fault_pte,
                                        bool writable)
static void numa_rebuild_large_mapping(struct vm_fault *vmf, struct vm_area_struct *vma,
                                       struct folio *folio, pte_t fault_pte,
                                       bool ignore_writable, bool pte_write_upgrade)
static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud)

numa_migrate_prep() is the only one which doesn't have vmf as the first
param.  It's a subtle inconsistency, but one you notice after a while
.. then wish you'd done right the first time, but can't quite bring
yourself to submit a patch to fix ;-)