linux-kernel - [PATCH AUTOSEL 3.18 3/5] net: qla3xxx: Remove overflowing shift statement

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Date:   Tue, 30 Oct 2018 09:32:32 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     stable@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Nathan Chancellor <natechancellor@...il.com>,
        "David S . Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 3.18 3/5] net: qla3xxx: Remove overflowing shift statement

From: Nathan Chancellor <natechancellor@...il.com>

[ Upstream commit 8c3bf9b62b667456a57aefcf1689e826df146159 ]

Clang currently warns:

drivers/net/ethernet/qlogic/qla3xxx.c:384:24: warning: signed shift
result (0xF00000000) requires 37 bits to represent, but 'int' only has
32 bits [-Wshift-overflow]
                    ((ISP_NVRAM_MASK << 16) | qdev->eeprom_cmd_data));
                      ~~~~~~~~~~~~~~ ^  ~~
1 warning generated.

The warning is certainly accurate since ISP_NVRAM_MASK is defined as
(0x000F << 16) which is then shifted by 16, resulting in 64424509440,
well above UINT_MAX.

Given that this is the only location in this driver where ISP_NVRAM_MASK
is shifted again, it seems likely that ISP_NVRAM_MASK was originally
defined without a shift and during the move of the shift to the
definition, this statement wasn't properly removed (since ISP_NVRAM_MASK
is used in the statenent right above this). Only the maintainers can
confirm this since this statment has been here since the driver was
first added to the kernel.

Link: https://github.com/ClangBuiltLinux/linux/issues/127
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/ethernet/qlogic/qla3xxx.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qla3xxx.c b/drivers/net/ethernet/qlogic/qla3xxx.c
index c2f09af5c25b..a51506b6901c 100644
--- a/drivers/net/ethernet/qlogic/qla3xxx.c
+++ b/drivers/net/ethernet/qlogic/qla3xxx.c
@@ -382,8 +382,6 @@ static void fm93c56a_select(struct ql3_adapter *qdev)
 
 	qdev->eeprom_cmd_data = AUBURN_EEPROM_CS_1;
 	ql_write_nvram_reg(qdev, spir, ISP_NVRAM_MASK | qdev->eeprom_cmd_data);
-	ql_write_nvram_reg(qdev, spir,
-			   ((ISP_NVRAM_MASK << 16) | qdev->eeprom_cmd_data));
 }
 
 /*
-- 
2.17.1