From: "Srivatsa S. Bhat (VMware)" <srivatsa@csail.mit.edu>

The comment that says mwait_play_dead() returns only on failure is a
bit misleading because mwait_play_dead() could actually return for
valid reasons (such as mwait not being supported by the platform) that
do not indicate a failure of the CPU offline operation. So, remove the
comment.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
---
 arch/x86/kernel/smpboot.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 55cad72715d9..9013bb28255a 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1833,7 +1833,7 @@ void native_play_dead(void)
 	play_dead_common();
 	tboot_shutdown(TB_SHUTDOWN_WFS);
 
-	mwait_play_dead();	/* Only returns on failure */
+	mwait_play_dead();
 	if (cpuidle_play_dead())
 		hlt_play_dead();
 }
-- 
2.25.1

Hi,

On 1/27/23 4:37 PM, Srivatsa S. Bhat wrote:
> From: "Srivatsa S. Bhat (VMware)" <srivatsa@csail.mit.edu>
> 
> The comment that says mwait_play_dead() returns only on failure is a
> bit misleading because mwait_play_dead() could actually return for
> valid reasons (such as mwait not being supported by the platform) that
> do not indicate a failure of the CPU offline operation. So, remove the
> comment.
> 
> Suggested-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>


Gentle ping for review. Thank you!

Regards,
Srivatsa

> ---
>  arch/x86/kernel/smpboot.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 55cad72715d9..9013bb28255a 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -1833,7 +1833,7 @@ void native_play_dead(void)
>  	play_dead_common();
>  	tboot_shutdown(TB_SHUTDOWN_WFS);
>  
> -	mwait_play_dead();	/* Only returns on failure */
> +	mwait_play_dead();
>  	if (cpuidle_play_dead())
>  		hlt_play_dead();
>  }
>

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID:     fcb3a81d221750d2a54b4e3a82b3efbbeab8780c
Gitweb:        https://git.kernel.org/tip/fcb3a81d221750d2a54b4e3a82b3efbbeab8780c
Author:        Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
AuthorDate:    Fri, 27 Jan 2023 16:37:51 -08:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Tue, 14 Feb 2023 23:44:34 +01:00

x86/hotplug: Remove incorrect comment about mwait_play_dead()

The comment that says mwait_play_dead() returns only on failure is a bit
misleading because mwait_play_dead() could actually return for valid
reasons (such as mwait not being supported by the platform) that do not
indicate a failure of the CPU offline operation. So, remove the comment.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230128003751.141317-1-srivatsa@csail.mit.edu

---
 arch/x86/kernel/smpboot.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 55cad72..9013bb2 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1833,7 +1833,7 @@ void native_play_dead(void)
 	play_dead_common();
 	tboot_shutdown(TB_SHUTDOWN_WFS);
 
-	mwait_play_dead();	/* Only returns on failure */
+	mwait_play_dead();
 	if (cpuidle_play_dead())
 		hlt_play_dead();
 }