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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue, 27 Apr 2021 11:54:17 -0700
Message-ID: <CAKwvOd=-NdUHevj9eBtKmihL8D0BSVyiOr9pMUNMYTWm1Y=KGg@mail.gmail.com>
Subject: Re: [PATCH] fs/ntfs: drop unneeded assignment in ntfs_perform_write()
To:     Yang Li <yang.lee@linux.alibaba.com>
Cc:     Anton Altaparmakov <anton@tuxera.com>,
        Nathan Chancellor <nathan@kernel.org>,
        linux-ntfs-dev@lists.sourceforge.net,
        LKML <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>,
        Nathan Huckleberry <nhuck15@gmail.com>
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On Sun, Apr 25, 2021 at 3:16 AM Yang Li <yang.lee@linux.alibaba.com> wrote:
>
> It is not required to initialize the local variable idx in
> ntfs_perform_write(), the value is never actually read from
> it.
>
> make clang-analyzer on x86_64 allyesconfig reports:
>
> fs/ntfs/file.c:1781:15: warning: Although the value stored to 'idx' is
> used in the enclosing expression, the value is never actually read from
> 'idx'
>
> Simplify the code and remove unneeded assignment to make clang-analyzer
> happy.

Thank you for the patch.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Is there someplace where I can learn more about "Abaci Robot?"  I'm
happy to see it running clang-analyzer. :)

>
> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
> ---
>  fs/ntfs/file.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
> index e5aab26..e39a26f 100644
> --- a/fs/ntfs/file.c
> +++ b/fs/ntfs/file.c
> @@ -1774,11 +1774,11 @@ static ssize_t ntfs_perform_write(struct file *file, struct iov_iter *i,
>         last_vcn = -1;
>         do {
>                 VCN vcn;
> -               pgoff_t idx, start_idx;
> +               pgoff_t start_idx;
>                 unsigned ofs, do_pages, u;
>                 size_t copied;
>
> -               start_idx = idx = pos >> PAGE_SHIFT;
> +               start_idx = pos >> PAGE_SHIFT;
>                 ofs = pos & ~PAGE_MASK;
>                 bytes = PAGE_SIZE - ofs;
>                 do_pages = 1;
> --
> 1.8.3.1
>
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-- 
Thanks,
~Nick Desaulniers