From: Abhinav Saxena <xandfury@gmail.com>
To: linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev
Cc: Shuah Khan <shuah@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Abhinav Saxena <xandfury@gmail.com>
Subject: [RFC PATCH 3/4] selftests/binderfs: Macro argument 'fd' may be better as '(fd)' to avoid precedence issues
Date: Wed, 15 May 2024 01:08:04 +0000 [thread overview]
Message-ID: <20240515010805.605511-4-xandfury@gmail.com> (raw)
In-Reply-To: <20240515010805.605511-1-xandfury@gmail.com>
Change the macro argument 'fd' to '(fd)' to avoid potential precedence
issues. Without parentheses, the macro expansion could lead to
unexpected behavior when used with an expression having different
precedence levels.
Example Code:
#define CALC_SQR_BAD(x) (x*x)
#define CALC_SQR_GOOD(x) ((x)*(x))
CALC_SQR_BAD(2+3) expands to 2+(3*3)+2, giving 11 as the incorrect
answer. Enclosing with parathesis CALC_SQR_GOOD(2+3) sets the correct
order of precedence and expands to (2+3)*(2+3), giving 25 as the
correct answer.
Signed-off-by: Abhinav Saxena <xandfury@gmail.com>
---
.../testing/selftests/filesystems/binderfs/binderfs_test.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
index 4a149e3d4ba4..d5dba6c1e07f 100644
--- a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
+++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
@@ -30,11 +30,11 @@
#define close_prot_errno_disarm(fd) \
do { \
- if (fd >= 0) { \
+ if ((fd) >= 0) { \
int _e_ = errno; \
- close(fd); \
+ close((fd)); \
errno = _e_; \
- fd = -EBADF; \
+ (fd) = -EBADF; \
} \
} while (false)
--
2.34.1
next prev parent reply other threads:[~2024-05-15 1:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-15 1:08 [RFC PATCH 0/4] selftests/binderfs: Fixes to binderfs_test Abhinav Saxena
2024-05-15 1:08 ` [RFC PATCH 1/4] selftests/binderfs: Run clang-format on binderfs test Abhinav Saxena
2024-05-15 1:08 ` [RFC PATCH 2/4] selftests/binderfs: Update close_prot_errno_disarm macro to do{...}while(false) structure for safety Abhinav Saxena
2024-05-15 1:08 ` Abhinav Saxena [this message]
2024-05-15 18:32 ` [RFC PATCH 3/4] selftests/binderfs: Macro argument 'fd' may be better as '(fd)' to avoid precedence issues Bill Wendling
2024-05-15 1:08 ` [RFC PATCH 4/4] selftests/binderfs: Add missing a blank line after declarations Abhinav Saxena
2024-05-15 4:27 ` [RFC PATCH 0/4] selftests/binderfs: Fixes to binderfs_test Abhinav Saxena
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240515010805.605511-4-xandfury@gmail.com \
--to=xandfury@gmail.com \
--cc=justinstitt@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=llvm@lists.linux.dev \
--cc=morbo@google.com \
--cc=nathan@kernel.org \
--cc=ndesaulniers@google.com \
--cc=shuah@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).