Re: [PATCH 17/20] filemap: consistently use ->f_mapping over ->i_mapping

[Christoph Hellwig <hch@xxxxxx>]

On Thu, Nov 19, 2020 at 03:13:16PM +0000, Matthew Wilcox wrote:
> On Wed, Nov 18, 2020 at 09:47:57AM +0100, Christoph Hellwig wrote:
> > @@ -2887,13 +2887,13 @@ EXPORT_SYMBOL(filemap_map_pages);
> >  vm_fault_t filemap_page_mkwrite(struct vm_fault *vmf)
> >  {
> >     struct page *page = vmf->page;
> > -   struct inode *inode = file_inode(vmf->vma->vm_file);
> > +   struct inode *inode = vmf->vma->vm_file->f_mapping->host;
> >     vm_fault_t ret = VM_FAULT_LOCKED;
> >  
> >     sb_start_pagefault(inode->i_sb);
> >     file_update_time(vmf->vma->vm_file);
> >     lock_page(page);
> > -   if (page->mapping != inode->i_mapping) {
> > +   if (page->mapping != vmf->vma->vm_file->f_mapping) {
> 
> Bit messy.  I'd do:
> 
>       struct address_space *mapping = vmf->vma->vm_file->f_mapping;
> 
>       sb_start_pagefault(mapping->host->i_sb);
> 
>       if (page->mapping != mapping)
> 
>       sb_end_pagefault(mapping->host->i_sb);

Fine with me.