Commit bc147f0f authored by Peng Zhang's avatar Peng Zhang Committed by Andrew Morton
Browse files

maple_tree: simplify mas_is_span_wr() 

Make the code for detecting spanning writes more concise.

Link: https://lkml.kernel.org/r/20230524031247.65949-5-zhangpeng.00@bytedance.com


Signed-off-by: default avatarPeng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: default avatarLiam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 14c4b5ab

lib/maple_tree.c

+11 −23
Original line number Diff line number Diff line
@@ -3728,43 +3728,31 @@ static inline void mas_store_root(struct ma_state *mas, void *entry) 
 */

static bool mas_is_span_wr(struct ma_wr_state *wr_mas)

{

	unsigned long max;

	unsigned long max = wr_mas->r_max;

	unsigned long last = wr_mas->mas->last;

	unsigned long piv = wr_mas->r_max;

	enum maple_type type = wr_mas->type;

	void *entry = wr_mas->entry;



	/* Contained in this pivot */

	if (piv > last)

	/* Contained in this pivot, fast path */

	if (last < max)

		return false;



	if (ma_is_leaf(type)) {

		max = wr_mas->mas->max;

	if (unlikely(ma_is_leaf(type))) {

		/* Fits in the node, but may span slots. */

		if (last < max)

			return false;

	}



		/* Writes to the end of the node but not null. */

		if ((last == max) && entry)

			return false;



	if (last == max) {

		/*

		 * Writing ULONG_MAX is not a spanning write regardless of the

		 * value being written as long as the range fits in the node.

		 * The last entry of leaf node cannot be NULL unless it is the

		 * rightmost node (writing ULONG_MAX), otherwise it spans slots.

		 */

		if ((last == ULONG_MAX) && (last == max))

			return false;

	} else if (piv == last) {

		if (entry)

			return false;



		/* Detect spanning store wr walk */

		if (last == ULONG_MAX)

		if (entry || last == ULONG_MAX)

			return false;

	}



	trace_ma_write(__func__, wr_mas->mas, piv, entry);



	trace_ma_write(__func__, wr_mas->mas, wr_mas->r_max, entry);

	return true;

}