linux-kernel - [PATCH] chelsio: use BUG() instead of BUG

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Date:   Mon, 25 Mar 2019 13:49:16 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Vishal Kulkarni <vishal@...lsio.com>,
        "David S. Miller" <davem@...emloft.net>
Cc:     clang-built-linux@...glegroups.com,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Nathan Chancellor <natechancellor@...il.com>,
        Arnd Bergmann <arnd@...db.de>,
        Ganesh Goudar <ganeshgr@...lsio.com>,
        Casey Leedom <leedom@...lsio.com>,
        Rahul Lakkireddy <rahul.lakkireddy@...lsio.com>,
        Arjun Vynipadath <arjun@...lsio.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] chelsio: use BUG() instead of BUG_ON(1)

clang warns about possible bugs in a dead code branch after
BUG_ON(1) when CONFIG_PROFILE_ALL_BRANCHES is enabled:

 drivers/net/ethernet/chelsio/cxgb4/sge.c:479:3: error: variable 'buf_size' is used uninitialized whenever 'if'
      condition is false [-Werror,-Wsometimes-uninitialized]
                BUG_ON(1);
                ^~~~~~~~~
 include/asm-generic/bug.h:61:36: note: expanded from macro 'BUG_ON'
 #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
                                   ^~~~~~~~~~~~~~~~~~~
 include/linux/compiler.h:48:23: note: expanded from macro 'unlikely'
 #  define unlikely(x)   (__branch_check__(x, 0, __builtin_constant_p(x)))
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 drivers/net/ethernet/chelsio/cxgb4/sge.c:482:9: note: uninitialized use occurs here
        return buf_size;
               ^~~~~~~~
 drivers/net/ethernet/chelsio/cxgb4/sge.c:479:3: note: remove the 'if' if its condition is always true
                BUG_ON(1);
                ^
 include/asm-generic/bug.h:61:32: note: expanded from macro 'BUG_ON'
 #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
                               ^
 drivers/net/ethernet/chelsio/cxgb4/sge.c:459:14: note: initialize the variable 'buf_size' to silence this warning
        int buf_size;
                    ^
                     = 0

Use BUG() here to create simpler code that clang understands
correctly.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c | 2 +-
 drivers/net/ethernet/chelsio/cxgb4/sge.c           | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
index 3130b43bba52..02959035ed3f 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
@@ -2620,7 +2620,7 @@ static inline struct port_info *ethqset2pinfo(struct adapter *adap, int qset)
 	}
 
 	/* should never happen! */
-	BUG_ON(1);
+	BUG();
 	return NULL;
 }
 
diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c b/drivers/net/ethernet/chelsio/cxgb4/sge.c
index 88773ca58e6b..b3da81e90132 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c
@@ -476,7 +476,7 @@ static inline int get_buf_size(struct adapter *adapter,
 		break;
 
 	default:
-		BUG_ON(1);
+		BUG();
 	}
 
 	return buf_size;
-- 
2.20.0