[PATCH 4/8] random: remove unused branch in hot code path

From: Stephan Müller
Date: Tue Dec 27 2016 - 17:45:50 EST


The variable ip is defined to be a __u64 which is always 8 bytes on any
architecture. Thus, the check for sizeof(ip) > 4 will always be true.

As the check happens in a hot code path, remove the branch.

Signed-off-by: Stephan Mueller <smueller@xxxxxxxxxx>
---
drivers/char/random.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 5c26b1c..8d4d720 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1136,8 +1136,7 @@ void add_interrupt_randomness(int irq, int irq_flags)
fast_pool->pool[1] ^= now ^ c_high;
ip = regs ? instruction_pointer(regs) : _RET_IP_;
fast_pool->pool[2] ^= ip;
- fast_pool->pool[3] ^= (sizeof(ip) > 4) ? ip >> 32 :
- get_reg(fast_pool, regs);
+ fast_pool->pool[3] ^= ip >> 32;

fast_mix(fast_pool);
add_interrupt_bench(cycles);
--
2.9.3