Date: Mon, 15 Jun 2020 16:38:37 +0800 From: Jason Yan <yanaijie@...wei.com> To: Chao Yu <yuchao0@...wei.com>, <jaegeuk@...nel.org>, <chao@...nel.org>, <linux-f2fs-devel@...ts.sourceforge.net>, <linux-kernel@...r.kernel.org> CC: Kees Cook <keescook@...omium.org>, <kernel-hardening@...ts.openwall.com> Subject: Re: [f2fs-dev] [PATCH] f2fs: Eliminate usage of uninitialized_var() macro 在 2020/6/15 16:26, Chao Yu 写道: > On 2020/6/15 12:02, Jason Yan wrote: >> This is an effort to eliminate the uninitialized_var() macro. >> >> The use of this macro is the wrong solution because it forces off ANY >> analysis by the compiler for a given variable. It even masks "unused >> variable" warnings. >> >> Quoted from Linus: >> >> "It's a horrible thing to use, in that it adds extra cruft to the >> source code, and then shuts up a compiler warning (even the _reliable_ >> warnings from gcc)." >> >> The gcc option "-Wmaybe-uninitialized" has been disabled and this change >> will not produce any warnnings even with "make W=1". >> >>  https://github.com/KSPP/linux/issues/81 >>  https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ >> >> Cc: Kees Cook <keescook@...omium.org> >> Signed-off-by: Jason Yan <yanaijie@...wei.com> >> --- >> fs/f2fs/data.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >> index 326c63879ddc..e6ec61274d76 100644 >> --- a/fs/f2fs/data.c >> +++ b/fs/f2fs/data.c >> @@ -2856,7 +2856,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping, >> }; >> #endif >> int nr_pages; >> - pgoff_t uninitialized_var(writeback_index); >> + pgoff_t writeback_index; > > I suggest to delete this variable directly, as we did for mm in > commit 28659cc8cc87 (mm/page-writeback.c: remove unused variable). > Good suggestion, I will send v2. Thanks, Jason > Thanks, > >> pgoff_t index; >> pgoff_t end; /* Inclusive */ >> pgoff_t done_index; >> > > . >
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