Re: [PATCH v2 1/3] xfs: Remove xfs_filemap_map_pages() wrapper

[Dave Chinner <david@fromorbit.com>]

On Mon, Mar 27, 2023 at 06:45:13PM +0100, Matthew Wilcox (Oracle) wrote:
> XFS doesn't actually need to be holding the XFS_MMAPLOCK_SHARED to do
> this.  filemap_map_pages() cannot bring new folios into the page cache
> and the folio lock is taken during filemap_map_pages() which provides
> sufficient protection against a truncation or hole punch.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  fs/xfs/xfs_file.c | 17 +----------------
>  1 file changed, 1 insertion(+), 16 deletions(-)
> 
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 863289aaa441..aede746541f8 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -1389,25 +1389,10 @@ xfs_filemap_pfn_mkwrite(
>  	return __xfs_filemap_fault(vmf, PE_SIZE_PTE, true);
>  }
>  
> -static vm_fault_t
> -xfs_filemap_map_pages(
> -	struct vm_fault		*vmf,
> -	pgoff_t			start_pgoff,
> -	pgoff_t			end_pgoff)
> -{
> -	struct inode		*inode = file_inode(vmf->vma->vm_file);
> -	vm_fault_t ret;
> -
> -	xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
> -	ret = filemap_map_pages(vmf, start_pgoff, end_pgoff);
> -	xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
> -	return ret;
> -}
> -
>  static const struct vm_operations_struct xfs_file_vm_ops = {
>  	.fault		= xfs_filemap_fault,
>  	.huge_fault	= xfs_filemap_huge_fault,
> -	.map_pages	= xfs_filemap_map_pages,
> +	.map_pages	= filemap_map_pages,
>  	.page_mkwrite	= xfs_filemap_page_mkwrite,
>  	.pfn_mkwrite	= xfs_filemap_pfn_mkwrite,
>  };
> -- 
> 2.39.2

Looks fine.

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com