On Wed, 25 Apr 2018, Souptick Joarder wrote:
> Use new return type vm_fault_t for fault handler. For
> now, this is just documenting that the function returns
> a VM_FAULT value rather than an errno. Once all instances
> are converted, vm_fault_t will become a distinct type.
>
> Commit 1c8f422059ae ("mm: change return type to vm_fault_t")
>
> Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx>
> Reviewed-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
> ---
> v2: Updated the change log
>
> include/linux/huge_mm.h | 5 +++--
> mm/huge_memory.c | 4 ++--
> 2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index a8a1262..d3bbf6b 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -3,6 +3,7 @@
> #define _LINUX_HUGE_MM_H
>
> #include <linux/sched/coredump.h>
> +#include <linux/mm_types.h>
>
> #include <linux/fs.h> /* only for vma_is_dax() */
>
> @@ -46,9 +47,9 @@ extern bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
> extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
> unsigned long addr, pgprot_t newprot,
> int prot_numa);
> -int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
> +vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
> pmd_t *pmd, pfn_t pfn, bool write);
> -int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
> +vm_fault_t vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
> pud_t *pud, pfn_t pfn, bool write);
> enum transparent_hugepage_flag {
> TRANSPARENT_HUGEPAGE_FLAG,
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 87ab9b8..1fe4705 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -755,7 +755,7 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
> spin_unlock(ptl);
> }
>
> -int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
> +vm_fault_t vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
> pmd_t *pmd, pfn_t pfn, bool write)
> {
> pgprot_t pgprot = vma->vm_page_prot;
> @@ -815,7 +815,7 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
> spin_unlock(ptl);
> }
>
> -int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
> +vm_fault_t vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
> pud_t *pud, pfn_t pfn, bool write)
> {
> pgprot_t pgprot = vma->vm_page_prot;
This isn't very useful unless functions that return the return value of
these functions, __dev_dax_{pmd,pud}_fault(), recast it as an int.
__dev_dax_pte_fault() would do the same thing, so it should logically also
be vm_fault_t, so then you would convert dev_dax_huge_fault() and
dev_dax_fault() as well in the same patch.
