[PATCH v2] scsi: ufs: Fix the build for gcc 9 and before

From: Bart Van Assche <bvanassche@acm.org>
To: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Naresh Kamboju <naresh.kamboju@linaro.org>,
	Nathan Chancellor <nathan@kernel.org>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	Stanley Chu <stanley.chu@mediatek.com>,
	Avri Altman <avri.altman@wdc.com>, Bean Huo <beanhuo@micron.com>,
	Asutosh Das <quic_asutoshd@quicinc.com>,
	"Bao D. Nguyen" <quic_nguyenb@quicinc.com>,
	Arthur Simchaev <Arthur.Simchaev@wdc.com>,
	Can Guo <quic_cang@quicinc.com>
Subject: [PATCH v2] scsi: ufs: Fix the build for gcc 9 and before
Date: Tue,  1 Aug 2023 16:21:50 -0700	[thread overview]
Message-ID: <20230801232204.1481902-1-bvanassche@acm.org> (raw)

gcc compilers before version 10 cannot do constant-folding for sub-byte
bitfields. This makes the compiler layout tests fail. Hence skip the
layout checks for gcc 9 and before.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/ufs/core/ufshcd.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 23335aaa6a66..4f5174735a4c 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -10564,6 +10564,14 @@ static const struct dev_pm_ops ufshcd_wl_pm_ops = {
 
 static void ufshcd_check_header_layout(void)
 {
+	/*
+	 * gcc compilers before version 10 cannot do constant-folding for
+	 * sub-byte bitfields. Hence skip the layout checks for gcc 9 and
+	 * before.
+	 */
+	if (IS_ENABLED(CONFIG_CC_IS_GCC) && CONFIG_GCC_VERSION < 100000)
+		return;
+
 	BUILD_BUG_ON(((u8 *)&(struct request_desc_header){
 				.cci = 3})[0] != 3);
 
