From: Jason Yan <yanaijie@huawei.com> To: <jaegeuk@kernel.org>, <chao@kernel.org>, <linux-f2fs-devel@lists.sourceforge.net>, <linux-kernel@vger.kernel.org> Cc: <kernel-hardening@lists.openwall.com>, Jason Yan <yanaijie@huawei.com>, Kees Cook <keescook@chromium.org>, Chao Yu <yuchao0@huawei.com> Subject: [PATCH] f2fs: Eliminate usage of uninitialized_var() macro Date: Mon, 15 Jun 2020 16:51:32 +0800 [thread overview] Message-ID: <20200615085132.166470-1-yanaijie@huawei.com> (raw) This is an effort to eliminate the uninitialized_var() macro[1]. 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[2]: "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)." Fix it by remove this variable since it is not needed at all. [1] https://github.com/KSPP/linux/issues/81 [2] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Cc: Kees Cook <keescook@chromium.org> Suggested-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jason Yan <yanaijie@huawei.com> --- v2: Directly remove this variable. fs/f2fs/data.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 326c63879ddc..3753ba06531b 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2856,7 +2856,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping, }; #endif int nr_pages; - pgoff_t uninitialized_var(writeback_index); pgoff_t index; pgoff_t end; /* Inclusive */ pgoff_t done_index; @@ -2875,8 +2874,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping, clear_inode_flag(mapping->host, FI_HOT_DATA); if (wbc->range_cyclic) { - writeback_index = mapping->writeback_index; /* prev offset */ - index = writeback_index; + index = mapping->writeback_index; /* prev offset */ end = -1; } else { index = wbc->range_start >> PAGE_SHIFT; -- 2.25.4
WARNING: multiple messages have this Message-ID (diff)
From: Jason Yan <yanaijie@huawei.com> To: <jaegeuk@kernel.org>, <chao@kernel.org>, <linux-f2fs-devel@lists.sourceforge.net>, <linux-kernel@vger.kernel.org> Cc: Jason Yan <yanaijie@huawei.com>, Kees Cook <keescook@chromium.org>, kernel-hardening@lists.openwall.com Subject: [f2fs-dev] [PATCH] f2fs: Eliminate usage of uninitialized_var() macro Date: Mon, 15 Jun 2020 16:51:32 +0800 [thread overview] Message-ID: <20200615085132.166470-1-yanaijie@huawei.com> (raw) This is an effort to eliminate the uninitialized_var() macro[1]. 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[2]: "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)." Fix it by remove this variable since it is not needed at all. [1] https://github.com/KSPP/linux/issues/81 [2] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Cc: Kees Cook <keescook@chromium.org> Suggested-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jason Yan <yanaijie@huawei.com> --- v2: Directly remove this variable. fs/f2fs/data.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 326c63879ddc..3753ba06531b 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2856,7 +2856,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping, }; #endif int nr_pages; - pgoff_t uninitialized_var(writeback_index); pgoff_t index; pgoff_t end; /* Inclusive */ pgoff_t done_index; @@ -2875,8 +2874,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping, clear_inode_flag(mapping->host, FI_HOT_DATA); if (wbc->range_cyclic) { - writeback_index = mapping->writeback_index; /* prev offset */ - index = writeback_index; + index = mapping->writeback_index; /* prev offset */ end = -1; } else { index = wbc->range_start >> PAGE_SHIFT; -- 2.25.4 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
next reply other threads:[~2020-06-15 8:50 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-15 8:51 Jason Yan [this message] 2020-06-15 8:51 ` [f2fs-dev] [PATCH] f2fs: Eliminate usage of uninitialized_var() macro Jason Yan 2020-06-15 9:04 ` Chao Yu 2020-06-15 9:04 ` [f2fs-dev] " Chao Yu 2020-06-15 20:11 ` Kees Cook 2020-06-15 20:11 ` [f2fs-dev] " Kees Cook -- strict thread matches above, loose matches on Subject: below -- 2020-06-15 4:02 Jason Yan
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