[PATCH v2] kernel/module: Use BUG_ON instead of if condition followed by BUG

[PATCH v2] kernel/module: Use BUG_ON instead of if condition followed by BUG

[zhouchuangao]

Fix the following coccinelle report:

kernel/module.c:1018:2-5:
WARNING: Use BUG_ON instead of if condition followed by BUG.

BUG_ON uses unlikely in if(). Through disassembly, we can see that
brk #0x800 is compiled to the end of the function.
As you can see below:
    ......
    ffffff8008660bec:   d65f03c0    ret
    ffffff8008660bf0:   d4210000    brk #0x800

Usually, the condition in if () is not satisfied. For the
multi-stage pipeline, we do not need to perform fetch decode
and excute operation on brk instruction.

In my opinion, this can improve the efficiency of the
multi-stage pipeline.

Signed-off-by: zhouchuangao <zhouchuangao@vivo.com>
---
 kernel/module.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index b5dd92e..faf9114 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1014,8 +1014,7 @@ void __symbol_put(const char *symbol)
 	};
 
 	preempt_disable();
-	if (!find_symbol(&fsa))
-		BUG();
+	BUG_ON(!find_symbol(&fsa));
 	module_put(fsa.owner);
 	preempt_enable();
 }
-- 
2.7.4

Re: [PATCH v2] kernel/module: Use BUG_ON instead of if condition followed by BUG

[Jessica Yu]

+++ zhouchuangao [12/05/21 07:01 -0700]:
>Fix the following coccinelle report:
>
>kernel/module.c:1018:2-5:
>WARNING: Use BUG_ON instead of if condition followed by BUG.
>
>BUG_ON uses unlikely in if(). Through disassembly, we can see that
>brk #0x800 is compiled to the end of the function.
>As you can see below:
>    ......
>    ffffff8008660bec:   d65f03c0    ret
>    ffffff8008660bf0:   d4210000    brk #0x800
>
>Usually, the condition in if () is not satisfied. For the
>multi-stage pipeline, we do not need to perform fetch decode
>and excute operation on brk instruction.
>
>In my opinion, this can improve the efficiency of the
>multi-stage pipeline.
>
>Signed-off-by: zhouchuangao <zhouchuangao@vivo.com>

Thanks for fixing the changelog. Queued on modules-next.

Jessica