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From: Lukas Bulwahn <lukas.bulwahn@gmail.com>
To: "Liam R . Howlett" <Liam.Howlett@oracle.com>,
	Matthew Wilcox <willy@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org,
	Lukas Bulwahn <lukas.bulwahn@gmail.com>
Subject: [PATCH 0/1] Dead stores in maple-tree
Date: Wed, 26 Oct 2022 14:00:28 +0200	[thread overview]
Message-ID: <20221026120029.12555-1-lukas.bulwahn@gmail.com> (raw)

Dear maple-tree authors, dear Liam, dear Matthew,

there are some Dead Stores that clang-analyzer reports:

lib/maple_tree.c:2906:2: warning: Value stored to 'last' is never read [clang-analyzer-deadcode.DeadStores]
lib/maple_tree.c:2907:2: warning: Value stored to 'prev_min' is never read [clang-analyzer-deadcode.DeadStores]

I addressed these two cases, which were most obvious and clear to fix;
see patch of this one-element series.

Further, clang-analyzer reports more, which I did not address:

lib/maple_tree.c:332:2: warning: Value stored to 'node' is never read [clang-analyzer-deadcode.DeadStores]
lib/maple_tree.c:337:2: warning: Value stored to 'node' is never read [clang-analyzer-deadcode.DeadStores]

Unclear to me if the tool is wrong or right in its analysis here for the two functions above.

lib/maple_tree.c:1212:23: warning: Value stored to 'nodep' during its initialization is never read [clang-analyzer-deadcode.DeadStores]

A lot of pointer magic. Unclear to me if the tool is wrong or right in its analysis here.

lib/maple_tree.c:5014:5: warning: Value stored to 'count' is never read [clang-analyzer-deadcode.DeadStores]

Unclear if the code is intended as it is now.

In mas_anode_descend(), the variable count is really just assigned and used once
effectively. The second assignment is never read. So, the variable count could
just be removed in mas_anode_descend().


Maybe these further warnings are helpful to clean up the code or find an issue
that was overlooked so far.


Best regards,

Lukas


Lukas Bulwahn (1):
  lib: maple_tree: remove unneeded initialization in mtree_range_walk()

 lib/maple_tree.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
2.17.1


             reply	other threads:[~2022-10-26 12:01 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-26 12:00 Lukas Bulwahn [this message]
2022-10-26 12:00 ` [PATCH 1/1] lib: maple_tree: remove unneeded initialization in mtree_range_walk() Lukas Bulwahn
2022-10-26 14:25   ` Liam Howlett
2022-10-26 14:23 ` [PATCH 0/1] Dead stores in maple-tree Liam Howlett
2022-10-27  7:43   ` Dan Carpenter
2022-10-27 17:16     ` Liam Howlett

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