From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
To: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, maple-tree@lists.infradead.org
Subject: Re: [PATCH 6/9] maple_tree: Remove a confusing check
Date: Tue, 25 Apr 2023 12:23:44 -0400 [thread overview]
Message-ID: <20230425162344.akgvzb2x5n6zsojh@revolver> (raw)
In-Reply-To: <20230425110511.11680-7-zhangpeng.00@bytedance.com>
* Peng Zhang <zhangpeng.00@bytedance.com> [230425 07:05]:
> After this loop, we are at the last slot of a node. Our purpose is to
> find an entry that is not NULL, but the pivot is checked here, delete
> it, and change to mas_logical_pivot() to get the pivot. Finally, only
> check whether the entry is NULL.
>
> Why is this confusing? If the pivot is equal to 0, but if the entry is
> not NULL at this time, it will return NULL because of the pivot, but it
> should not do this, the entry is valid.
Please avoid titles that don't say much at all.. and it's borderline
insulting. I could go into the reasons this was written this way, but
that would be a waste of time.. which is another reason to focus on what
you did in your commit message.
I've removed this function entirely in my patch set, so this isn't
needed.
>
> Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
> ---
> lib/maple_tree.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index 7f4b2ce84ce61..83441ef2e1f57 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -4742,17 +4742,13 @@ static inline void *mas_next_nentry(struct ma_state *mas,
> return NULL;
> }
>
> - pivot = mas_safe_pivot(mas, pivots, mas->offset, type);
> + pivot = mas_logical_pivot(mas, pivots, mas->offset, type);
> entry = mas_slot(mas, slots, mas->offset);
> if (ma_dead_node(node))
> return NULL;
>
> - if (!pivot)
> - return NULL;
> -
> if (!entry)
> return NULL;
> -
> found:
> mas->last = pivot;
> return entry;
> --
> 2.20.1
>
next prev parent reply other threads:[~2023-04-25 16:24 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-25 11:05 [PATCH 0/9] fix, rework and clean up for maple tree Peng Zhang
2023-04-25 11:05 ` [PATCH 1/9] maple_tree: Fix allocation when min is equal to max in mas_empty_area/_area_rev() Peng Zhang
2023-04-25 11:05 ` [PATCH 2/9] maple_tree: Make maple state reusable after mas_empty_area() Peng Zhang
2023-04-25 16:00 ` Liam R. Howlett
2023-04-25 11:05 ` [PATCH 3/9] maple_tree: Modify the allocation method of mtree_alloc_range/rrange() Peng Zhang
2023-04-25 16:08 ` Liam R. Howlett
2023-04-26 12:34 ` Peng Zhang
2023-04-27 1:10 ` Liam R. Howlett
2023-04-25 11:05 ` [PATCH 4/9] maple_tree: Update mtree_alloc_rrange() and mtree_alloc_range() testing Peng Zhang
2023-04-25 16:09 ` Liam R. Howlett
2023-04-25 11:05 ` [PATCH 5/9] maple_tree: Remove an if statement that cannot be true Peng Zhang
2023-04-25 16:16 ` Liam R. Howlett
2023-04-25 11:05 ` [PATCH 6/9] maple_tree: Remove a confusing check Peng Zhang
2023-04-25 16:23 ` Liam R. Howlett [this message]
2023-04-25 11:05 ` [PATCH 7/9] maple_tree: Delete redundant code in mas_next_node() Peng Zhang
2023-04-25 16:45 ` Liam R. Howlett
2023-04-26 11:43 ` Peng Zhang
2023-04-25 11:05 ` [PATCH 8/9] maple_tree: Remove the redundant check of mas->offset in mas_empty_area/area_rev() Peng Zhang
2023-04-25 17:00 ` Liam R. Howlett
2023-04-25 11:05 ` [PATCH 9/9] maple_tree: Move declaration of mas_empty_area_rev() to a better place Peng Zhang
2023-04-25 17:04 ` Liam R. Howlett
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