[PATCH] [12/16] Refactor truncate to allow direct truncating of page

Andi Kleen
2009-06-03T18:49:29Z

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]

Signed-off-by: Andi Kleen <ak@linux.intel.com>

---
include/linux/mm.h | 2 ++
mm/truncate.c | 24 ++++++++++++------------
2 files changed, 14 insertions(+), 12 deletions(-)

Index: linux/mm/truncate.c
===================================================================
--- linux.orig/mm/truncate.c 2009-06-03 19:37:38.000000000 +0200
+++ linux/mm/truncate.c 2009-06-03 20:13:43.000000000 +0200
@@ -135,6 +135,16 @@
return ret;
}

+void 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);
+ }
+ truncate_complete_page(mapping, page);
+}
+
/**
* truncate_inode_pages - truncate range of pages specified by start & end byte offsets
* @mapping: mapping to truncate
@@ -196,12 +206,7 @@
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 +243,10 @@
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 2009-06-03 19:37:38.000000000 +0200
+++ linux/include/linux/mm.h 2009-06-03 20:39:49.000000000 +0200
@@ -811,6 +811,8 @@
extern int vmtruncate(struct inode * inode, loff_t offset);
extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);

+void 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, int write_access);