[PATCH] xen/common: Constify the parameter of _spin_is_locked()

[PATCH] xen/common: Constify the parameter of _spin_is_locked()

[Julien Grall]

From: Julien Grall <jgrall@amazon.com>

The lock is not meant to be modified by _spin_is_locked(). So constify
it.

This is helpful to be able to assert the locked is taken when the
underlying structure is const.

Signed-off-by: Julien Grall <jgrall@amazon.com>
---
 xen/common/spinlock.c      | 2 +-
 xen/include/xen/spinlock.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index 84996c3fbc1f..a15f0a2eb667 100644
--- a/xen/common/spinlock.c
+++ b/xen/common/spinlock.c
@@ -368,7 +368,7 @@ void _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
     local_irq_restore(flags);
 }
 
-int _spin_is_locked(spinlock_t *lock)
+int _spin_is_locked(const spinlock_t *lock)
 {
     /*
      * Recursive locks may be locked by another CPU, yet we return
diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index 2fa6ba36548e..ca40c71c88f9 100644
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -185,7 +185,7 @@ void _spin_unlock(spinlock_t *lock);
 void _spin_unlock_irq(spinlock_t *lock);
 void _spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags);
 
-int _spin_is_locked(spinlock_t *lock);
+int _spin_is_locked(const spinlock_t *lock);
 int _spin_trylock(spinlock_t *lock);
 void _spin_barrier(spinlock_t *lock);
 
-- 
2.38.1

RE: [PATCH] xen/common: Constify the parameter of _spin_is_locked()

[Henry Wang]

Hi Julien,

> -----Original Message-----
> Subject: [PATCH] xen/common: Constify the parameter of _spin_is_locked()
> 
> From: Julien Grall <jgrall@amazon.com>
> 
> The lock is not meant to be modified by _spin_is_locked(). So constify
> it.
> 
> This is helpful to be able to assert the locked is taken when the

Nit: s/locked/lock/
This definitely can be fixed on commit.

> underlying structure is const.
> 
> Signed-off-by: Julien Grall <jgrall@amazon.com>

I tried to test this patch on FVP (both Arm32 and Arm64) to play safe.
This patch is good (as expected of course :)), so:

Reviewed-by: Henry Wang <Henry.Wang@arm.com>
Tested-by: Henry Wang <Henry.Wang@arm.com> #Arm

Kind regards,
Henry

Re: [PATCH] xen/common: Constify the parameter of _spin_is_locked()

[Jan Beulich]

On 27.01.2023 20:05, Julien Grall wrote:
> From: Julien Grall <jgrall@amazon.com>
> 
> The lock is not meant to be modified by _spin_is_locked(). So constify
> it.
> 
> This is helpful to be able to assert the locked is taken when the
> underlying structure is const.
> 
> Signed-off-by: Julien Grall <jgrall@amazon.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>

But: Could I talk you into doing the same for _rw_is{,_write}_locked() for
consistency?

Jan

Re: [PATCH] xen/common: Constify the parameter of _spin_is_locked()

[Julien Grall]

On 30/01/2023 08:11, Jan Beulich wrote:
> On 27.01.2023 20:05, Julien Grall wrote:
>> From: Julien Grall <jgrall@amazon.com>
>>
>> The lock is not meant to be modified by _spin_is_locked(). So constify
>> it.
>>
>> This is helpful to be able to assert the locked is taken when the
>> underlying structure is const.
>>
>> Signed-off-by: Julien Grall <jgrall@amazon.com>
> 
> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> 
> But: Could I talk you into doing the same for _rw_is{,_write}_locked() for
> consistency?

Sure. Although, I would prefer to do it in a separate patch.

Cheers,

-- 
Julien Grall