From: Jeremy Kerr <j...@ozlabs.org> [ Upstream commit 5d4bac9a5f4ef24b2482529bda6661a58e5b5b65 ]
Although irqreturn_t is an enum, we treat it (and its enumeration constants) as a bitmask. However, bad_action_ret() uses a less-than operator to determine whether an irqreturn_t falls within allowable bit values, which means we need to know the signededness of an enum type to read the logic, which is implementation-dependent. This change explicitly uses an unsigned type for the comparison. We do this instead of changing to a bitwise test, as the latter compiles to increased instructions in this hot path. It looks like we get the correct behaviour currently (bad_action_ret(-1) returns 1), so this is purely a readability fix. Signed-off-by: Jeremy Kerr <j...@ozlabs.org> Link: http://lkml.kernel.org/r/1487219049-4061-1-git-send-email...@ozlabs.org Signed-off-by: Thomas Gleixner <t...@linutronix.de> Signed-off-by: Sasha Levin <alexander.le...@verizon.com> --- kernel/irq/spurious.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c index 5707f97a3e6a..061ba7eed4ed 100644 --- a/kernel/irq/spurious.c +++ b/kernel/irq/spurious.c @@ -175,7 +175,9 @@ out: static inline int bad_action_ret(irqreturn_t action_ret) { - if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD))) + unsigned int r = action_ret; + + if (likely(r <= (IRQ_HANDLED | IRQ_WAKE_THREAD))) return 0; return 1; } -- 2.11.0
