[PATCH] x86/qspinlock: Fix compile error

[Peter Zijlstra]

commit b987ffc18fb3b3b76b059aa9e372dbee26f7c4f2 upstream

With a compiler that has asm-goto but not asm-cc-output and
CONFIG_PROFILE_ALL_BRANCHES=y we get a compiler error:

  arch/x86/include/asm/rmwcc.h:23:17: error: jump into statement expression

Fix this by writing the if() as a boolean multiplication instead.

Reported-by: kbuild test robot <lkp@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Fixes: 7aa54be29765 ("locking/qspinlock, x86: Provide liveness guarantee")
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
---
 arch/x86/include/asm/qspinlock.h | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h
index f784b95e44df..f0f2dd74b8c9 100644
--- a/arch/x86/include/asm/qspinlock.h
+++ b/arch/x86/include/asm/qspinlock.h
@@ -19,10 +19,14 @@ static __always_inline bool __queued_RMW_btsl(struct qspinlock *lock)
 
 static __always_inline u32 queued_fetch_set_pending_acquire(struct qspinlock *lock)
 {
-	u32 val = 0;
+	u32 val;
 
-	if (__queued_RMW_btsl(lock))
-		val |= _Q_PENDING_VAL;
+	/*
+	 * We can't use GEN_BINARY_RMWcc() inside an if() stmt because asm goto
+	 * and CONFIG_PROFILE_ALL_BRANCHES=y results in a label inside a
+	 * statement expression, which GCC doesn't like.
+	 */
+	val = __queued_RMW_btsl(lock) * _Q_PENDING_VAL;
 
 	val |= atomic_read(&lock->val) & ~_Q_PENDING_MASK;
 
-- 
2.11.0


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