[v6,3/6] coroutine-lock: Store the coroutine in the CoWaitRecord only once

Commit Message

Paolo Bonzini March 25, 2021, 11:29 a.m. UTC

From: David Edmondson <[e-mail]>

When taking the slow path for mutex acquisition, set the coroutine
value in the CoWaitRecord in push_waiter(), rather than both there and
in the caller.

Reviewed-by: Paolo Bonzini <[e-mail]>
Reviewed-by: Philippe Mathieu-Daudé <[e-mail]>
Signed-off-by: David Edmondson <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Paolo Bonzini <[e-mail]>
---
 util/qemu-coroutine-lock.c | 1 -
 1 file changed, 1 deletion(-)

Comments

Stefan Hajnoczi March 30, 2021, 3:29 p.m. UTC | #1

On Thu, Mar 25, 2021 at 12:29:38PM +0100, Paolo Bonzini wrote:
> From: David Edmondson <[e-mail]>
> 
> When taking the slow path for mutex acquisition, set the coroutine
> value in the CoWaitRecord in push_waiter(), rather than both there and
> in the caller.
> 
> Reviewed-by: Paolo Bonzini <[e-mail]>
> Reviewed-by: Philippe Mathieu-Daudé <[e-mail]>
> Signed-off-by: David Edmondson <[e-mail]>
> Message-Id: <[e-mail]>
> Signed-off-by: Paolo Bonzini <[e-mail]>
> ---
>  util/qemu-coroutine-lock.c | 1 -
>  1 file changed, 1 deletion(-)

Reviewed-by: Stefan Hajnoczi <[e-mail]>

Patch

diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index 5816bf8900..eb73cf11dc 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -204,7 +204,6 @@  static void coroutine_fn qemu_co_mutex_lock_slowpath(AioContext *ctx,
     unsigned old_handoff;
 
     trace_qemu_co_mutex_lock_entry(mutex, self);
-    w.co = self;
     push_waiter(mutex, &w);
 
     /* This is the "Responsibility Hand-Off" protocol; a lock() picks from