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Commit edcd1d84 authored by Cesar Eduardo Barros's avatar Cesar Eduardo Barros Committed by Linus Torvalds
Browse files

radix-tree: fix radix_tree_prev_hole() underflow case 



radix_tree_prev_hole() used LONG_MAX to detect underflow; however,
ULONG_MAX is clearly what was intended, both here and by its only user
(count_history_pages at mm/readahead.c).

Reviewed-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: default avatarCesar Eduardo Barros <cesarb@cesarb.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9d85cba7

lib/radix-tree.c

+2 −2
Original line number Diff line number Diff line
@@ -656,7 +656,7 @@ EXPORT_SYMBOL(radix_tree_next_hole); 
 *

 *	Returns: the index of the hole if found, otherwise returns an index

 *	outside of the set specified (in which case 'index - return >= max_scan'

 *	will be true). In rare cases of wrap-around, LONG_MAX will be returned.

 *	will be true). In rare cases of wrap-around, ULONG_MAX will be returned.

 *

 *	radix_tree_next_hole may be called under rcu_read_lock. However, like

 *	radix_tree_gang_lookup, this will not atomically search a snapshot of
@@ -674,7 +674,7 @@ unsigned long radix_tree_prev_hole(struct radix_tree_root *root, 
		if (!radix_tree_lookup(root, index))

			break;

		index--;

		if (index == LONG_MAX)

		if (index == ULONG_MAX)

			break;

	}