[PATCH v2 05/19] maple_tree: Drop dead code from mas_extend_spanning_null()

["Liam R. Howlett (Oracle)" <liam@infradead.org>]

mas_extend_spanning_null() had a clause if the end of the range being
written (mas->last) is the same as the end of the existing range it is
overwriting (wr_mas->r_max), action will be taken.

This code path is not possible because the only calling function
increments mas->last (unless it's ULONG_MAX) to walk to one beyond the
write and then resets the value back to the initial value.

In the case of mas->last == ULONG_MAX, then the second part of the
statement will always be false - mas->last cannot be less than the node
max.

This code never executed and is flawed anyways (the arguments are
incorrectly ordered), so removing it is the safest action.  Since the
code never executes, it is not fixing any issue so Fixes tag is not
given.

Signed-off-by: Liam R. Howlett (Oracle) <liam@infradead.org>
---
 lib/maple_tree.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index e2f7474572319..97849db132e7a 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -2996,13 +2996,6 @@ static inline void mas_extend_spanning_null(struct ma_wr_state *l_wr_mas,
 		if (r_mas->last < r_wr_mas->r_max)
 			r_mas->last = r_wr_mas->r_max;
 		r_mas->offset++;
-	} else if ((r_mas->last == r_wr_mas->r_max) &&
-	    (r_mas->last < r_mas->max) &&
-	    !mas_slot_locked(r_mas, r_wr_mas->slots, r_mas->offset + 1)) {
-		r_mas->last = mas_safe_pivot(r_mas, r_wr_mas->pivots,
-					     r_wr_mas->type, r_mas->offset + 1);
-		r_mas->offset++;
-		r_wr_mas->r_max = r_mas->last;
 	}
 }
 
-- 
2.47.3