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authorNick Piggin <npiggin@suse.de>2008-07-25 19:45:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-26 12:00:06 -0700
commit30002ed2e41830ec03ec3e577ad83ac6b188f96e (patch)
tree13896f3038e391eb41246455239d7678cf51b011
parent652ea695364142b2464744746beac206d050ef19 (diff)
mm: readahead scan lockless
radix_tree_next_hole() is implemented as a series of radix_tree_lookup()s. So it can be called locklessly, under rcu_read_lock(). 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>
-rw-r--r--mm/readahead.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/readahead.c b/mm/readahead.c
index d8723a5f649..77e8ddf945e 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -382,9 +382,9 @@ ondemand_readahead(struct address_space *mapping,
if (hit_readahead_marker) {
pgoff_t start;
- read_lock_irq(&mapping->tree_lock);
- start = radix_tree_next_hole(&mapping->page_tree, offset, max+1);
- read_unlock_irq(&mapping->tree_lock);
+ rcu_read_lock();
+ start = radix_tree_next_hole(&mapping->page_tree, offset,max+1);
+ rcu_read_unlock();
if (!start || start - offset > max)
return 0;