From bc147f0f70a3f0ce3f3978d9476a4e894e1aad88 Mon Sep 17 00:00:00 2001 From: Peng Zhang Date: Wed, 24 May 2023 11:12:41 +0800 Subject: [PATCH] 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: Peng Zhang Reviewed-by: Liam R. Howlett Signed-off-by: Andrew Morton --- lib/maple_tree.c | 34 +++++++++++----------------------- 1 file changed, 11 insertions(+), 23 deletions(-) diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 3fe6a66..41a105e 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -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; - max = wr_mas->mas->max; - if (unlikely(ma_is_leaf(type))) { - /* Fits in the node, but may span slots. */ + if (ma_is_leaf(type)) { + max = wr_mas->mas->max; 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; } -- 2.7.4