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authorLinus Torvalds <torvalds@linux-foundation.org>2017-09-06 20:49:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-06 20:49:49 -0700
commitd34fc1adf01ff87026da85fb972dc259dc347540 (patch)
tree27356073d423187157b7cdb69da32b53102fb9e7 /mm/filemap.c
parent1c9fe4409ce3e9c78b1ed96ee8ed699d4f03bf33 (diff)
parentd2cd9ede6e193dd7d88b6d27399e96229a551b19 (diff)
downloadlinux-d34fc1adf01ff87026da85fb972dc259dc347540.tar.bz2
Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton: - various misc bits - DAX updates - OCFS2 - most of MM * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (119 commits) mm,fork: introduce MADV_WIPEONFORK x86,mpx: make mpx depend on x86-64 to free up VMA flag mm: add /proc/pid/smaps_rollup mm: hugetlb: clear target sub-page last when clearing huge page mm: oom: let oom_reap_task and exit_mmap run concurrently swap: choose swap device according to numa node mm: replace TIF_MEMDIE checks by tsk_is_oom_victim mm, oom: do not rely on TIF_MEMDIE for memory reserves access z3fold: use per-cpu unbuddied lists mm, swap: don't use VMA based swap readahead if HDD is used as swap mm, swap: add sysfs interface for VMA based swap readahead mm, swap: VMA based swap readahead mm, swap: fix swap readahead marking mm, swap: add swap readahead hit statistics mm/vmalloc.c: don't reinvent the wheel but use existing llist API mm/vmstat.c: fix wrong comment selftests/memfd: add memfd_create hugetlbfs selftest mm/shmem: add hugetlbfs support to memfd_create() mm, devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups mm/vmalloc.c: halve the number of comparisons performed in pcpu_get_vm_areas() ...
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c67
1 files changed, 39 insertions, 28 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 1e01cb6e5173..9d21afd692b9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -130,17 +130,8 @@ static int page_cache_tree_insert(struct address_space *mapping,
return -EEXIST;
mapping->nrexceptional--;
- if (!dax_mapping(mapping)) {
- if (shadowp)
- *shadowp = p;
- } else {
- /* DAX can replace empty locked entry with a hole */
- WARN_ON_ONCE(p !=
- dax_radix_locked_entry(0, RADIX_DAX_EMPTY));
- /* Wakeup waiters for exceptional entry lock */
- dax_wake_mapping_entry_waiter(mapping, page->index, p,
- true);
- }
+ if (shadowp)
+ *shadowp = p;
}
__radix_tree_replace(&mapping->page_tree, node, slot, page,
workingset_update_node, mapping);
@@ -402,8 +393,7 @@ bool filemap_range_has_page(struct address_space *mapping,
{
pgoff_t index = start_byte >> PAGE_SHIFT;
pgoff_t end = end_byte >> PAGE_SHIFT;
- struct pagevec pvec;
- bool ret;
+ struct page *page;
if (end_byte < start_byte)
return false;
@@ -411,12 +401,10 @@ bool filemap_range_has_page(struct address_space *mapping,
if (mapping->nrpages == 0)
return false;
- pagevec_init(&pvec, 0);
- if (!pagevec_lookup(&pvec, mapping, index, 1))
+ if (!find_get_pages_range(mapping, &index, end, 1, &page))
return false;
- ret = (pvec.pages[0]->index <= end);
- pagevec_release(&pvec);
- return ret;
+ put_page(page);
+ return true;
}
EXPORT_SYMBOL(filemap_range_has_page);
@@ -1564,23 +1552,29 @@ export:
}
/**
- * find_get_pages - gang pagecache lookup
+ * find_get_pages_range - gang pagecache lookup
* @mapping: The address_space to search
* @start: The starting page index
+ * @end: The final page index (inclusive)
* @nr_pages: The maximum number of pages
* @pages: Where the resulting pages are placed
*
- * find_get_pages() will search for and return a group of up to
- * @nr_pages pages in the mapping. The pages are placed at @pages.
- * find_get_pages() takes a reference against the returned pages.
+ * find_get_pages_range() will search for and return a group of up to @nr_pages
+ * pages in the mapping starting at index @start and up to index @end
+ * (inclusive). The pages are placed at @pages. find_get_pages_range() takes
+ * a reference against the returned pages.
*
* The search returns a group of mapping-contiguous pages with ascending
* indexes. There may be holes in the indices due to not-present pages.
+ * We also update @start to index the next page for the traversal.
*
- * find_get_pages() returns the number of pages which were found.
+ * find_get_pages_range() returns the number of pages which were found. If this
+ * number is smaller than @nr_pages, the end of specified range has been
+ * reached.
*/
-unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
- unsigned int nr_pages, struct page **pages)
+unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
+ pgoff_t end, unsigned int nr_pages,
+ struct page **pages)
{
struct radix_tree_iter iter;
void **slot;
@@ -1590,8 +1584,11 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
return 0;
rcu_read_lock();
- radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
+ radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, *start) {
struct page *head, *page;
+
+ if (iter.index > end)
+ break;
repeat:
page = radix_tree_deref_slot(slot);
if (unlikely(!page))
@@ -1627,11 +1624,25 @@ repeat:
}
pages[ret] = page;
- if (++ret == nr_pages)
- break;
+ if (++ret == nr_pages) {
+ *start = pages[ret - 1]->index + 1;
+ goto out;
+ }
}
+ /*
+ * We come here when there is no page beyond @end. We take care to not
+ * overflow the index @start as it confuses some of the callers. This
+ * breaks the iteration when there is page at index -1 but that is
+ * already broken anyway.
+ */
+ if (end == (pgoff_t)-1)
+ *start = (pgoff_t)-1;
+ else
+ *start = end + 1;
+out:
rcu_read_unlock();
+
return ret;
}