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authorMatthew Wilcox <willy@infradead.org>2017-11-03 13:30:42 -0400
committerMatthew Wilcox <willy@infradead.org>2018-09-29 22:47:49 -0400
commit3159f943aafdbacb2f94c38fdaadabf2bbde2a14 (patch)
tree7e06823a1ab7e90774535d17a217a939bdddda3b /mm/filemap.c
parent66ee620f06f99d72475db6eb638559ba608c7dee (diff)
downloadlinux-3159f943aafdbacb2f94c38fdaadabf2bbde2a14.tar.bz2
xarray: Replace exceptional entries
Introduce xarray value entries and tagged pointers to replace radix tree exceptional entries. This is a slight change in encoding to allow the use of an extra bit (we can now store BITS_PER_LONG - 1 bits in a value entry). It is also a change in emphasis; exceptional entries are intimidating and different. As the comment explains, you can choose to store values or pointers in the xarray and they are both first-class citizens. Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Josef Bacik <jbacik@fb.com>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 52517f28e6f4..4de14e75c4ec 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -127,7 +127,7 @@ static int page_cache_tree_insert(struct address_space *mapping,
p = radix_tree_deref_slot_protected(slot,
&mapping->i_pages.xa_lock);
- if (!radix_tree_exceptional_entry(p))
+ if (!xa_is_value(p))
return -EEXIST;
mapping->nrexceptional--;
@@ -336,7 +336,7 @@ page_cache_tree_delete_batch(struct address_space *mapping,
break;
page = radix_tree_deref_slot_protected(slot,
&mapping->i_pages.xa_lock);
- if (radix_tree_exceptional_entry(page))
+ if (xa_is_value(page))
continue;
if (!tail_pages) {
/*
@@ -1355,7 +1355,7 @@ pgoff_t page_cache_next_hole(struct address_space *mapping,
struct page *page;
page = radix_tree_lookup(&mapping->i_pages, index);
- if (!page || radix_tree_exceptional_entry(page))
+ if (!page || xa_is_value(page))
break;
index++;
if (index == 0)
@@ -1396,7 +1396,7 @@ pgoff_t page_cache_prev_hole(struct address_space *mapping,
struct page *page;
page = radix_tree_lookup(&mapping->i_pages, index);
- if (!page || radix_tree_exceptional_entry(page))
+ if (!page || xa_is_value(page))
break;
index--;
if (index == ULONG_MAX)
@@ -1539,7 +1539,7 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset,
repeat:
page = find_get_entry(mapping, offset);
- if (radix_tree_exceptional_entry(page))
+ if (xa_is_value(page))
page = NULL;
if (!page)
goto no_page;