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mm: implement ->map_pages for page cache

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filemap_map_pages() is generic implementation of ->map_pages() for
filesystems who uses page cache.

It should be safe to use filemap_map_pages() for ->map_pages() if
filesystem use filemap_fault() for ->fault().

Signed-off-by: Kirill A. Shutemov <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Ning Qu <[email protected]>
Cc: Hugh Dickins <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Kirill A. Shutemov 2014-04-07 15:37:19 -07:00 • committed by Linus Torvalds
commit f1820361f8
14 changed files with 93 additions and 0 deletions
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74
mm/filemap.c
View file

@ -33,6 +33,7 @@
#include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
#include <linux/memcontrol.h>
#include <linux/cleancache.h>
#include <linux/rmap.h>
#include "internal.h"
#define CREATE_TRACE_POINTS
@ -2064,6 +2065,78 @@ page_not_uptodate:
}
EXPORT_SYMBOL(filemap_fault);
void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct radix_tree_iter iter;
void **slot;
struct file *file = vma->vm_file;
struct address_space *mapping = file->f_mapping;
loff_t size;
struct page *page;
unsigned long address = (unsigned long) vmf->virtual_address;
unsigned long addr;
pte_t *pte;
rcu_read_lock();
radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, vmf->pgoff) {
if (iter.index > vmf->max_pgoff)
break;
repeat:
page = radix_tree_deref_slot(slot);
if (unlikely(!page))
goto next;
if (radix_tree_exception(page)) {
if (radix_tree_deref_retry(page))
break;
else
goto next;
}
if (!page_cache_get_speculative(page))
goto repeat;
/* Has the page moved? */
if (unlikely(page != *slot)) {
page_cache_release(page);
goto repeat;
}
if (!PageUptodate(page) ||
PageReadahead(page) ||
PageHWPoison(page))
goto skip;
if (!trylock_page(page))
goto skip;
if (page->mapping != mapping || !PageUptodate(page))
goto unlock;
size = i_size_read(mapping->host) + PAGE_CACHE_SIZE - 1;
if (page->index >= size >> PAGE_CACHE_SHIFT)
goto unlock;
pte = vmf->pte + page->index - vmf->pgoff;
if (!pte_none(*pte))
goto unlock;
if (file->f_ra.mmap_miss > 0)
file->f_ra.mmap_miss--;
addr = address + (page->index - vmf->pgoff) * PAGE_SIZE;
do_set_pte(vma, addr, page, pte, false, false);
unlock_page(page);
goto next;
unlock:
unlock_page(page);
skip:
page_cache_release(page);
next:
if (iter.index == vmf->max_pgoff)
break;
}
rcu_read_unlock();
}
EXPORT_SYMBOL(filemap_map_pages);
int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct page *page = vmf->page;
@ -2093,6 +2166,7 @@ EXPORT_SYMBOL(filemap_page_mkwrite);
const struct vm_operations_struct generic_file_vm_ops = {
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = filemap_page_mkwrite,
.remap_pages = generic_file_remap_pages,
};