The patch titled
Subject: mm: add find_get_entries_tag()
has been added to the -mm tree. Its filename is
mm-add-find_get_entries_tag.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-add-find_get_entries_tag.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-add-find_get_entries_tag.patch
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------------------------------------------------------
From: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Subject: mm: add find_get_entries_tag()
Add find_get_entries_tag() to the family of functions that include
find_get_entries(), find_get_pages() and find_get_pages_tag(). This is
needed for DAX dirty page handling because we need a list of both page
offsets and radix tree entries ('indices' and 'entries' in this function)
that are marked with the PAGECACHE_TAG_TOWRITE tag.
Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: "J. Bruce Fields" <bfields@xxxxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pagemap.h | 3 +
mm/filemap.c | 68 ++++++++++++++++++++++++++++++++++++++
2 files changed, 71 insertions(+)
diff -puN include/linux/pagemap.h~mm-add-find_get_entries_tag include/linux/pagemap.h
--- a/include/linux/pagemap.h~mm-add-find_get_entries_tag
+++ a/include/linux/pagemap.h
@@ -361,6 +361,9 @@ unsigned find_get_pages_contig(struct ad
unsigned int nr_pages, struct page **pages);
unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
int tag, unsigned int nr_pages, struct page **pages);
+unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
+ int tag, unsigned int nr_entries,
+ struct page **entries, pgoff_t *indices);
struct page *grab_cache_page_write_begin(struct address_space *mapping,
pgoff_t index, unsigned flags);
diff -puN mm/filemap.c~mm-add-find_get_entries_tag mm/filemap.c
--- a/mm/filemap.c~mm-add-find_get_entries_tag
+++ a/mm/filemap.c
@@ -1499,6 +1499,74 @@ repeat:
}
EXPORT_SYMBOL(find_get_pages_tag);
+/**
+ * find_get_entries_tag - find and return entries that match @tag
+ * @mapping: the address_space to search
+ * @start: the starting page cache index
+ * @tag: the tag index
+ * @nr_entries: the maximum number of entries
+ * @entries: where the resulting entries are placed
+ * @indices: the cache indices corresponding to the entries in @entries
+ *
+ * Like find_get_entries, except we only return entries which are tagged with
+ * @tag.
+ */
+unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
+ int tag, unsigned int nr_entries,
+ struct page **entries, pgoff_t *indices)
+{
+ void **slot;
+ unsigned int ret = 0;
+ struct radix_tree_iter iter;
+
+ if (!nr_entries)
+ return 0;
+
+ rcu_read_lock();
+restart:
+ radix_tree_for_each_tagged(slot, &mapping->page_tree,
+ &iter, start, tag) {
+ struct page *page;
+repeat:
+ page = radix_tree_deref_slot(slot);
+ if (unlikely(!page))
+ continue;
+ if (radix_tree_exception(page)) {
+ if (radix_tree_deref_retry(page)) {
+ /*
+ * Transient condition which can only trigger
+ * when entry at index 0 moves out of or back
+ * to root: none yet gotten, safe to restart.
+ */
+ goto restart;
+ }
+
+ /*
+ * A shadow entry of a recently evicted page, a swap
+ * entry from shmem/tmpfs or a DAX entry. Return it
+ * without attempting to raise page count.
+ */
+ goto export;
+ }
+ if (!page_cache_get_speculative(page))
+ goto repeat;
+
+ /* Has the page moved? */
+ if (unlikely(page != *slot)) {
+ page_cache_release(page);
+ goto repeat;
+ }
+export:
+ indices[ret] = iter.index;
+ entries[ret] = page;
+ if (++ret == nr_entries)
+ break;
+ }
+ rcu_read_unlock();
+ return ret;
+}
+EXPORT_SYMBOL(find_get_entries_tag);
+
/*
* CD/DVDs are error prone. When a medium error occurs, the driver may fail
* a _large_ part of the i/o request. Imagine the worst scenario:
_
Patches currently in -mm which might be from ross.zwisler@xxxxxxxxxxxxxxx are
mm-dax-fix-livelock-allow-dax-pmd-mappings-to-become-writeable.patch
pmem-add-wb_cache_pmem-to-the-pmem-api.patch
dax-support-dirty-dax-entries-in-radix-tree.patch
mm-add-find_get_entries_tag.patch
dax-add-support-for-fsync-sync.patch
ext2-call-dax_pfn_mkwrite-for-dax-fsync-msync.patch
ext4-call-dax_pfn_mkwrite-for-dax-fsync-msync.patch
xfs-call-dax_pfn_mkwrite-for-dax-fsync-msync.patch
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