[PATCH v5 3/3] x86/mce/mce-inject: Return appropriate error code if CPUs are offline

[Smita Koralahalli]

Assign appropriate error code when no CPUs are available online.

Return this error code with appropriate message to user when injection
fails.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@xxxxxxx>
Reviewed-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
---
Link:
https://lkml.kernel.org/r/20220214233640.70510-3-Smita.KoralahalliChannabasappa@xxxxxxx

v2:
	Added pr_err() along with error code.
v3:
	Rephrased the statement: No online CPUs available for error
	injection -> Chosen CPU is not online.
v4:
	Prefixed "mce-inject" so the user knows that the message is
	coming from this module.
	Printed CPU number along with the error message.
v5:
	Used the new descriptor for writing errors.
---
 arch/x86/kernel/cpu/mce/inject.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c
index cce068a4478c..efae0e938293 100644
--- a/arch/x86/kernel/cpu/mce/inject.c
+++ b/arch/x86/kernel/cpu/mce/inject.c
@@ -575,8 +575,11 @@ static int do_inject(void)
 	}
 
 	cpus_read_lock();
-	if (!cpu_online(cpu))
+	if (!cpu_online(cpu)) {
+		pr_err("mce-inject: Chosen CPU %d is not online\n", cpu);
+		inj_desc.err = -ENODEV;
 		goto err;
+	}
 
 	toggle_hw_mce_inject(cpu, true);
 
-- 
2.17.1