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authorNick Piggin <npiggin@suse.de>2008-07-25 19:45:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-26 12:00:06 -0700
commit19fd6231279be3c3bdd02ed99f9b0eb195978064 (patch)
treeee09121054262d73c551b57114acd855b82a7a82 /mm/swap_state.c
parenta60637c85893e7191faaafa6a72e197c24386727 (diff)
downloadlinux-19fd6231279be3c3bdd02ed99f9b0eb195978064.tar.gz
mm: spinlock tree_lock
mapping->tree_lock has no read lockers.  convert the lock from an rwlock
to a spinlock.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swap_state.c')
-rw-r--r--mm/swap_state.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 3e3381d6c7ee..2c217e33d497 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -39,7 +39,7 @@ static struct backing_dev_info swap_backing_dev_info = {
 
 struct address_space swapper_space = {
 	.page_tree	= RADIX_TREE_INIT(GFP_ATOMIC|__GFP_NOWARN),
-	.tree_lock	= __RW_LOCK_UNLOCKED(swapper_space.tree_lock),
+	.tree_lock	= __SPIN_LOCK_UNLOCKED(swapper_space.tree_lock),
 	.a_ops		= &swap_aops,
 	.i_mmap_nonlinear = LIST_HEAD_INIT(swapper_space.i_mmap_nonlinear),
 	.backing_dev_info = &swap_backing_dev_info,
@@ -80,7 +80,7 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
 		SetPageSwapCache(page);
 		set_page_private(page, entry.val);
 
-		write_lock_irq(&swapper_space.tree_lock);
+		spin_lock_irq(&swapper_space.tree_lock);
 		error = radix_tree_insert(&swapper_space.page_tree,
 						entry.val, page);
 		if (likely(!error)) {
@@ -88,7 +88,7 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
 			__inc_zone_page_state(page, NR_FILE_PAGES);
 			INC_CACHE_INFO(add_total);
 		}
-		write_unlock_irq(&swapper_space.tree_lock);
+		spin_unlock_irq(&swapper_space.tree_lock);
 		radix_tree_preload_end();
 
 		if (unlikely(error)) {
@@ -182,9 +182,9 @@ void delete_from_swap_cache(struct page *page)
 
 	entry.val = page_private(page);
 
-	write_lock_irq(&swapper_space.tree_lock);
+	spin_lock_irq(&swapper_space.tree_lock);
 	__delete_from_swap_cache(page);
-	write_unlock_irq(&swapper_space.tree_lock);
+	spin_unlock_irq(&swapper_space.tree_lock);
 
 	swap_free(entry);
 	page_cache_release(page);