Re: [PATCH] [11/19] HWPOISON: Refactor truncate to allow direct truncating of page v2

Nick Piggin
2009-08-05T10:20:06Z

On Wed, Aug 05, 2009 at 11:36:38AM +0200, Andi Kleen wrote:
>
> From: Nick Piggin <npiggin@suse.de>
>
> Extract out truncate_inode_page() out of the truncate path so that
> it can be used by memory-failure.c
>
> [AK: description, headers, fix typos]
> v2: Some white space changes from Fengguang Wu
>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
>
> ---
> include/linux/mm.h | 2 ++
> mm/truncate.c | 29 +++++++++++++++--------------
> 2 files changed, 17 insertions(+), 14 deletions(-)
>
> Index: linux/mm/truncate.c
> ===================================================================
> --- linux.orig/mm/truncate.c
> +++ linux/mm/truncate.c
> @@ -93,11 +93,11 @@ EXPORT_SYMBOL(cancel_dirty_page);
> * its lock, b) when a concurrent invalidate_mapping_pages got there first and
> * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
> */
> -static void
> +static int
> truncate_complete_page(struct address_space *mapping, struct page *page)
> {
> if (page->mapping != mapping)
> - return;
> + return -EIO;

Hmm, at this point, the page must have been removed from pagecache,
so I don't know if you need to pass an error back?

> if (page_has_private(page))
> do_invalidatepage(page, 0);
> @@ -108,6 +108,7 @@ truncate_complete_page(struct address_sp
> remove_from_page_cache(page);
> ClearPageMappedToDisk(page);
> page_cache_release(page); /* pagecache ref */
> + return 0;
> }
>
> /*
> @@ -135,6 +136,16 @@ invalidate_complete_page(struct address_
> return ret;
> }
>
> +int truncate_inode_page(struct address_space *mapping, struct page *page)
> +{
> + if (page_mapped(page)) {
> + unmap_mapping_range(mapping,
> + (loff_t)page->index << PAGE_CACHE_SHIFT,
> + PAGE_CACHE_SIZE, 0);
> + }
> + return truncate_complete_page(mapping, page);
> +}
> +
> /**
> * truncate_inode_pages - truncate range of pages specified by start & end byte offsets
> * @mapping: mapping to truncate
> @@ -196,12 +207,7 @@ void truncate_inode_pages_range(struct a
> unlock_page(page);
> continue;
> }
> - if (page_mapped(page)) {
> - unmap_mapping_range(mapping,
> - (loff_t)page_index<<PAGE_CACHE_SHIFT,
> - PAGE_CACHE_SIZE, 0);
> - }
> - truncate_complete_page(mapping, page);
> + truncate_inode_page(mapping, page);
> unlock_page(page);
> }
> pagevec_release(&pvec);
> @@ -238,15 +244,10 @@ void truncate_inode_pages_range(struct a
> break;
> lock_page(page);
> wait_on_page_writeback(page);
> - if (page_mapped(page)) {
> - unmap_mapping_range(mapping,
> - (loff_t)page->index<<PAGE_CACHE_SHIFT,
> - PAGE_CACHE_SIZE, 0);
> - }
> + truncate_inode_page(mapping, page);
> if (page->index > next)
> next = page->index;
> next++;
> - truncate_complete_page(mapping, page);
> unlock_page(page);
> }
> pagevec_release(&pvec);
> Index: linux/include/linux/mm.h
> ===================================================================
> --- linux.orig/include/linux/mm.h
> +++ linux/include/linux/mm.h
> @@ -809,6 +809,8 @@ static inline void unmap_shared_mapping_
> extern int vmtruncate(struct inode * inode, loff_t offset);
> extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
>
> +int truncate_inode_page(struct address_space *mapping, struct page *page);
> +
> #ifdef CONFIG_MMU
> extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
> unsigned long address, unsigned int flags);