page cache: use xa_lock

Remove the address_space ->tree_lock and use the xa_lock newly added to
the radix_tree_root.  Rename the address_space ->page_tree to ->i_pages,
since we don't really care that it's a tree.

[willy@infradead.org: fix nds32, fs/dax.c]
  Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 16 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index 51b55f2d2db5..f65dd69e1fd1 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -467,20 +467,21 @@ int migrate_page_move_mapping(struct address_space *mapping,
 	oldzone = page_zone(page);
 	newzone = page_zone(newpage);
 
-	spin_lock_irq(&mapping->tree_lock);
+	xa_lock_irq(&mapping->i_pages);
 
-	pslot = radix_tree_lookup_slot(&mapping->page_tree,
+	pslot = radix_tree_lookup_slot(&mapping->i_pages,
  					page_index(page));
 
 	expected_count += 1 + page_has_private(page);
 	if (page_count(page) != expected_count ||
-		radix_tree_deref_slot_protected(pslot, &mapping->tree_lock) != page) {
-		spin_unlock_irq(&mapping->tree_lock);
+		radix_tree_deref_slot_protected(pslot,
+					&mapping->i_pages.xa_lock) != page) {
+		xa_unlock_irq(&mapping->i_pages);
 		return -EAGAIN;
 	}
 
 	if (!page_ref_freeze(page, expected_count)) {
-		spin_unlock_irq(&mapping->tree_lock);
+		xa_unlock_irq(&mapping->i_pages);
 		return -EAGAIN;
 	}
 
@@ -494,7 +495,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
 	if (mode == MIGRATE_ASYNC && head &&
 			!buffer_migrate_lock_buffers(head, mode)) {
 		page_ref_unfreeze(page, expected_count);
-		spin_unlock_irq(&mapping->tree_lock);
+		xa_unlock_irq(&mapping->i_pages);
 		return -EAGAIN;
 	}
 
@@ -522,7 +523,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
 		SetPageDirty(newpage);
 	}
 
-	radix_tree_replace_slot(&mapping->page_tree, pslot, newpage);
+	radix_tree_replace_slot(&mapping->i_pages, pslot, newpage);
 
 	/*
 	 * Drop cache reference from old page by unfreezing
@@ -531,7 +532,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
 	 */
 	page_ref_unfreeze(page, expected_count - 1);
 
-	spin_unlock(&mapping->tree_lock);
+	xa_unlock(&mapping->i_pages);
 	/* Leave irq disabled to prevent preemption while updating stats */
 
 	/*
@@ -574,20 +575,19 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
 	int expected_count;
 	void **pslot;
 
-	spin_lock_irq(&mapping->tree_lock);
+	xa_lock_irq(&mapping->i_pages);
 
-	pslot = radix_tree_lookup_slot(&mapping->page_tree,
-					page_index(page));
+	pslot = radix_tree_lookup_slot(&mapping->i_pages, page_index(page));
 
 	expected_count = 2 + page_has_private(page);
 	if (page_count(page) != expected_count ||
-		radix_tree_deref_slot_protected(pslot, &mapping->tree_lock) != page) {
-		spin_unlock_irq(&mapping->tree_lock);
+		radix_tree_deref_slot_protected(pslot, &mapping->i_pages.xa_lock) != page) {
+		xa_unlock_irq(&mapping->i_pages);
 		return -EAGAIN;
 	}
 
 	if (!page_ref_freeze(page, expected_count)) {
-		spin_unlock_irq(&mapping->tree_lock);
+		xa_unlock_irq(&mapping->i_pages);
 		return -EAGAIN;
 	}
 
@@ -596,11 +596,11 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
 
 	get_page(newpage);
 
-	radix_tree_replace_slot(&mapping->page_tree, pslot, newpage);
+	radix_tree_replace_slot(&mapping->i_pages, pslot, newpage);
 
 	page_ref_unfreeze(page, expected_count - 1);
 
-	spin_unlock_irq(&mapping->tree_lock);
+	xa_unlock_irq(&mapping->i_pages);
 
 	return MIGRATEPAGE_SUCCESS;
 }