linux-kernel - [PATCH v13 36/72] mm: Convert truncate to XArray

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 11 Jun 2018 07:06:03 -0700
From:   Matthew Wilcox <willy@...radead.org>
To:     linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Matthew Wilcox <mawilcox@...rosoft.com>, Jan Kara <jack@...e.cz>,
        Jeff Layton <jlayton@...hat.com>,
        Lukas Czerner <lczerner@...hat.com>,
        Ross Zwisler <ross.zwisler@...ux.intel.com>,
        Christoph Hellwig <hch@....de>,
        Goldwyn Rodrigues <rgoldwyn@...e.com>,
        Nicholas Piggin <npiggin@...il.com>,
        Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>,
        linux-nilfs@...r.kernel.org, Jaegeuk Kim <jaegeuk@...nel.org>,
        Chao Yu <yuchao0@...wei.com>,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: [PATCH v13 36/72] mm: Convert truncate to XArray

From: Matthew Wilcox <mawilcox@...rosoft.com>

This is essentially xa_cmpxchg() with the locking handled above us,
and it doesn't have to handle replacing a NULL entry.

Signed-off-by: Matthew Wilcox <mawilcox@...rosoft.com>
---
 mm/truncate.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/mm/truncate.c b/mm/truncate.c
index ed778555c9f3..45d68e90b703 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -33,15 +33,12 @@
 static inline void __clear_shadow_entry(struct address_space *mapping,
 				pgoff_t index, void *entry)
 {
-	struct radix_tree_node *node;
-	void **slot;
+	XA_STATE(xas, &mapping->i_pages, index);
 
-	if (!__radix_tree_lookup(&mapping->i_pages, index, &node, &slot))
+	xas_set_update(&xas, workingset_update_node);
+	if (xas_load(&xas) != entry)
 		return;
-	if (*slot != entry)
-		return;
-	__radix_tree_replace(&mapping->i_pages, node, slot, NULL,
-			     workingset_update_node);
+	xas_store(&xas, NULL);
 	mapping->nrexceptional--;
 }
 
@@ -738,10 +735,10 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 		index++;
 	}
 	/*
-	 * For DAX we invalidate page tables after invalidating radix tree.  We
+	 * For DAX we invalidate page tables after invalidating page cache.  We
 	 * could invalidate page tables while invalidating each entry however
 	 * that would be expensive. And doing range unmapping before doesn't
-	 * work as we have no cheap way to find whether radix tree entry didn't
+	 * work as we have no cheap way to find whether page cache entry didn't
 	 * get remapped later.
 	 */
 	if (dax_mapping(mapping)) {
-- 
2.17.1