linux-kernel - [PATCH v6 63/99] dax: Convert dax_insert_mapping

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Message-Id: <20180117202203.19756-64-willy@infradead.org>
Date:   Wed, 17 Jan 2018 12:21:27 -0800
From:   Matthew Wilcox <willy@...radead.org>
To:     linux-kernel@...r.kernel.org
Cc:     Matthew Wilcox <mawilcox@...rosoft.com>, linux-mm@...ck.org,
        linux-fsdevel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-nilfs@...r.kernel.org, linux-btrfs@...r.kernel.org,
        linux-xfs@...r.kernel.org, linux-usb@...r.kernel.org,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Stefano Stabellini <sstabellini@...nel.org>,
        iommu@...ts.linux-foundation.org, linux-remoteproc@...r.kernel.org,
        linux-s390@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
        cgroups@...r.kernel.org, linux-sh@...r.kernel.org,
        David Howells <dhowells@...hat.com>
Subject: [PATCH v6 63/99] dax: Convert dax_insert_mapping_entry to XArray

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

Signed-off-by: Matthew Wilcox <mawilcox@...rosoft.com>
---
 fs/dax.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index e6b25ef112f2..494e8fb7a98f 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -498,9 +498,9 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
 				      void *entry, sector_t sector,
 				      unsigned long flags, bool dirty)
 {
-	struct radix_tree_root *pages = &mapping->pages;
 	void *new_entry;
 	pgoff_t index = vmf->pgoff;
+	XA_STATE(xas, &mapping->pages, index);
 
 	if (dirty)
 		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
@@ -516,7 +516,7 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
 					PAGE_SIZE, 0);
 	}
 
-	xa_lock_irq(&mapping->pages);
+	xas_lock_irq(&xas);
 	new_entry = dax_radix_locked_entry(sector, flags);
 
 	if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
@@ -528,21 +528,15 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
 		 * existing entry is a PMD, we will just leave the PMD in the
 		 * tree and dirty it if necessary.
 		 */
-		struct radix_tree_node *node;
-		void **slot;
-		void *ret;
-
-		ret = __radix_tree_lookup(pages, index, &node, &slot);
-		WARN_ON_ONCE(ret != entry);
-		__radix_tree_replace(pages, node, slot,
-				     new_entry, NULL);
+		void *prev = xas_store(&xas, new_entry);
+		WARN_ON_ONCE(prev != entry);
 		entry = new_entry;
 	}
 
 	if (dirty)
-		radix_tree_tag_set(pages, index, PAGECACHE_TAG_DIRTY);
+		xas_set_tag(&xas, PAGECACHE_TAG_DIRTY);
 
-	xa_unlock_irq(&mapping->pages);
+	xas_unlock_irq(&xas);
 	return entry;
 }
 
-- 
2.15.1