[PATCH v8 2/6] powerpc/code-patching: Use WARN_ON and fix check in poking_init

[Benjamin Gray <bgray@linux.ibm.com>]

From: "Christopher M. Riedl" <cmr@bluescreens.de>

The latest kernel docs list BUG_ON() as 'deprecated' and that they
should be replaced with WARN_ON() (or pr_warn()) when possible. The
BUG_ON() in poking_init() warrants a WARN_ON() rather than a pr_warn()
since the error condition is deemed "unreachable".

Also take this opportunity to fix the failure check in the WARN_ON():
cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, ...) returns a positive integer
on success and a negative integer on failure.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
---
 arch/powerpc/lib/code-patching.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index ad0cf3108dd0..34fc7ac34d91 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -81,16 +81,13 @@ static int text_area_cpu_down(unsigned int cpu)
 
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(poking_init_done);
 
-/*
- * Although BUG_ON() is rude, in this case it should only happen if ENOMEM, and
- * we judge it as being preferable to a kernel that will crash later when
- * someone tries to use patch_instruction().
- */
 void __init poking_init(void)
 {
-	BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
-		"powerpc/text_poke:online", text_area_cpu_up,
-		text_area_cpu_down));
+	WARN_ON(cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
+				  "powerpc/text_poke:online",
+				  text_area_cpu_up,
+				  text_area_cpu_down) < 0);
+
 	static_branch_enable(&poking_init_done);
 }
 
-- 
2.37.3