[PATCH] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

[PATCH] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

[Waiman Long]

Both is_rwsem_reader_owned() and rwsem_owner() are currently only used when
CONFIG_DEBUG_RWSEMS is defined. This causes a compilation error with clang
when `make W=1` and CONFIG_WERROR=y:

kernel/locking/rwsem.c:187:20: error: unused function 'is_rwsem_reader_owned' [-Werror,-Wunused-function]
  187 | static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
      |                    ^~~~~~~~~~~~~~~~~~~~~
kernel/locking/rwsem.c:271:35: error: unused function 'rwsem_owner' [-Werror,-Wunused-function]
  271 | static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
      |                                   ^~~~~~~~~~~

Fix this by moving these two functions under the CONFIG_DEBUG_RWSEMS define.

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Waiman Long <longman@redhat.com>
---
 kernel/locking/rwsem.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 33cac79e3994..4b041e9c408f 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -181,12 +181,21 @@ static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
 	__rwsem_set_reader_owned(sem, current);
 }
 
+#ifdef CONFIG_DEBUG_RWSEMS
+/*
+ * Return just the real task structure pointer of the owner
+ */
+static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
+{
+	return (struct task_struct *)
+		(atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK);
+}
+
 /*
  * Return true if the rwsem is owned by a reader.
  */
 static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
 {
-#ifdef CONFIG_DEBUG_RWSEMS
 	/*
 	 * Check the count to see if it is write-locked.
 	 */
@@ -194,11 +203,9 @@ static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
 
 	if (count & RWSEM_WRITER_MASK)
 		return false;
-#endif
 	return rwsem_test_oflags(sem, RWSEM_READER_OWNED);
 }
 
-#ifdef CONFIG_DEBUG_RWSEMS
 /*
  * With CONFIG_DEBUG_RWSEMS configured, it will make sure that if there
  * is a task pointer in owner of a reader-owned rwsem, it will be the
@@ -265,15 +272,6 @@ static inline bool rwsem_write_trylock(struct rw_semaphore *sem)
 	return false;
 }
 
-/*
- * Return just the real task structure pointer of the owner
- */
-static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
-{
-	return (struct task_struct *)
-		(atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK);
-}
-
 /*
  * Return the real task structure pointer of the owner and the embedded
  * flags in the owner. pflags must be non-NULL.
-- 
2.43.5

Re: [PATCH] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

[Andy Shevchenko]

On Mon, Sep 09, 2024 at 02:29:05PM -0400, Waiman Long wrote:
> Both is_rwsem_reader_owned() and rwsem_owner() are currently only used when
> CONFIG_DEBUG_RWSEMS is defined. This causes a compilation error with clang
> when `make W=1` and CONFIG_WERROR=y:
> 
> kernel/locking/rwsem.c:187:20: error: unused function 'is_rwsem_reader_owned' [-Werror,-Wunused-function]
>   187 | static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
>       |                    ^~~~~~~~~~~~~~~~~~~~~
> kernel/locking/rwsem.c:271:35: error: unused function 'rwsem_owner' [-Werror,-Wunused-function]
>   271 | static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
>       |                                   ^~~~~~~~~~~
> 
> Fix this by moving these two functions under the CONFIG_DEBUG_RWSEMS define.

At least this solves my issue,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Thanks!

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

[Andy Shevchenko]

On Tue, Sep 10, 2024 at 11:15:54AM +0300, Andy Shevchenko wrote:
> On Mon, Sep 09, 2024 at 02:29:05PM -0400, Waiman Long wrote:
> > Both is_rwsem_reader_owned() and rwsem_owner() are currently only used when
> > CONFIG_DEBUG_RWSEMS is defined. This causes a compilation error with clang
> > when `make W=1` and CONFIG_WERROR=y:
> > 
> > kernel/locking/rwsem.c:187:20: error: unused function 'is_rwsem_reader_owned' [-Werror,-Wunused-function]
> >   187 | static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
> >       |                    ^~~~~~~~~~~~~~~~~~~~~
> > kernel/locking/rwsem.c:271:35: error: unused function 'rwsem_owner' [-Werror,-Wunused-function]
> >   271 | static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
> >       |                                   ^~~~~~~~~~~
> > 
> > Fix this by moving these two functions under the CONFIG_DEBUG_RWSEMS define.
> 
> At least this solves my issue,
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

...and

Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

[Waiman Long]

On 9/10/24 04:16, Andy Shevchenko wrote:
> On Tue, Sep 10, 2024 at 11:15:54AM +0300, Andy Shevchenko wrote:
>> On Mon, Sep 09, 2024 at 02:29:05PM -0400, Waiman Long wrote:
>>> Both is_rwsem_reader_owned() and rwsem_owner() are currently only used when
>>> CONFIG_DEBUG_RWSEMS is defined. This causes a compilation error with clang
>>> when `make W=1` and CONFIG_WERROR=y:
>>>
>>> kernel/locking/rwsem.c:187:20: error: unused function 'is_rwsem_reader_owned' [-Werror,-Wunused-function]
>>>    187 | static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
>>>        |                    ^~~~~~~~~~~~~~~~~~~~~
>>> kernel/locking/rwsem.c:271:35: error: unused function 'rwsem_owner' [-Werror,-Wunused-function]
>>>    271 | static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
>>>        |                                   ^~~~~~~~~~~
>>>
>>> Fix this by moving these two functions under the CONFIG_DEBUG_RWSEMS define.
>> At least this solves my issue,
>> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ...and
>
> Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Thanks for the testing.

No functional change is intended for this patch. Ingo & Peter, can this 
patch lands in v6.12 or has to wait until v6.13?

Thanks,
Longman

Re: [PATCH] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

[Andy Shevchenko]

On Tue, Sep 10, 2024 at 11:47:17AM -0400, Waiman Long wrote:
> On 9/10/24 04:16, Andy Shevchenko wrote:
> > On Tue, Sep 10, 2024 at 11:15:54AM +0300, Andy Shevchenko wrote:
> > > On Mon, Sep 09, 2024 at 02:29:05PM -0400, Waiman Long wrote:
> > > > Both is_rwsem_reader_owned() and rwsem_owner() are currently only used when
> > > > CONFIG_DEBUG_RWSEMS is defined. This causes a compilation error with clang
> > > > when `make W=1` and CONFIG_WERROR=y:
> > > > 
> > > > kernel/locking/rwsem.c:187:20: error: unused function 'is_rwsem_reader_owned' [-Werror,-Wunused-function]
> > > >    187 | static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
> > > >        |                    ^~~~~~~~~~~~~~~~~~~~~
> > > > kernel/locking/rwsem.c:271:35: error: unused function 'rwsem_owner' [-Werror,-Wunused-function]
> > > >    271 | static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
> > > >        |                                   ^~~~~~~~~~~
> > > > 
> > > > Fix this by moving these two functions under the CONFIG_DEBUG_RWSEMS define.
> > > At least this solves my issue,
> > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > ...and
> > 
> > Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
> Thanks for the testing.
> 
> No functional change is intended for this patch. Ingo & Peter, can this
> patch lands in v6.12 or has to wait until v6.13?

I see it already in PeterZ's tree.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

[Waiman Long]

On 9/10/24 12:01, Andy Shevchenko wrote:
> On Tue, Sep 10, 2024 at 11:47:17AM -0400, Waiman Long wrote:
>> On 9/10/24 04:16, Andy Shevchenko wrote:
>>> On Tue, Sep 10, 2024 at 11:15:54AM +0300, Andy Shevchenko wrote:
>>>> On Mon, Sep 09, 2024 at 02:29:05PM -0400, Waiman Long wrote:
>>>>> Both is_rwsem_reader_owned() and rwsem_owner() are currently only used when
>>>>> CONFIG_DEBUG_RWSEMS is defined. This causes a compilation error with clang
>>>>> when `make W=1` and CONFIG_WERROR=y:
>>>>>
>>>>> kernel/locking/rwsem.c:187:20: error: unused function 'is_rwsem_reader_owned' [-Werror,-Wunused-function]
>>>>>     187 | static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
>>>>>         |                    ^~~~~~~~~~~~~~~~~~~~~
>>>>> kernel/locking/rwsem.c:271:35: error: unused function 'rwsem_owner' [-Werror,-Wunused-function]
>>>>>     271 | static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
>>>>>         |                                   ^~~~~~~~~~~
>>>>>
>>>>> Fix this by moving these two functions under the CONFIG_DEBUG_RWSEMS define.
>>>> At least this solves my issue,
>>>> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>>> ...and
>>>
>>> Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>> Thanks for the testing.
>>
>> No functional change is intended for this patch. Ingo & Peter, can this
>> patch lands in v6.12 or has to wait until v6.13?
> I see it already in PeterZ's tree.
>
Right. It is in PeterZ's tree. I didn't check his tree that often. 
Thanks for letting me know.

Cheers,
Longman

[tip: locking/core] locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

[tip-bot2 for Waiman Long]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     d00b83d416e73bc3fa4d21b14bec920e88b70ce6
Gitweb:        https://git.kernel.org/tip/d00b83d416e73bc3fa4d21b14bec920e88b70ce6
Author:        Waiman Long <longman@redhat.com>
AuthorDate:    Mon, 09 Sep 2024 14:29:05 -04:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 10 Sep 2024 12:02:33 +02:00

locking/rwsem: Move is_rwsem_reader_owned() and rwsem_owner() under CONFIG_DEBUG_RWSEMS

Both is_rwsem_reader_owned() and rwsem_owner() are currently only used when
CONFIG_DEBUG_RWSEMS is defined. This causes a compilation error with clang
when `make W=1` and CONFIG_WERROR=y:

kernel/locking/rwsem.c:187:20: error: unused function 'is_rwsem_reader_owned' [-Werror,-Wunused-function]
  187 | static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
      |                    ^~~~~~~~~~~~~~~~~~~~~
kernel/locking/rwsem.c:271:35: error: unused function 'rwsem_owner' [-Werror,-Wunused-function]
  271 | static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
      |                                   ^~~~~~~~~~~

Fix this by moving these two functions under the CONFIG_DEBUG_RWSEMS define.

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240909182905.161156-1-longman@redhat.com
---
 kernel/locking/rwsem.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 33cac79..4b041e9 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -181,12 +181,21 @@ static inline void rwsem_set_reader_owned(struct rw_semaphore *sem)
 	__rwsem_set_reader_owned(sem, current);
 }
 
+#ifdef CONFIG_DEBUG_RWSEMS
+/*
+ * Return just the real task structure pointer of the owner
+ */
+static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
+{
+	return (struct task_struct *)
+		(atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK);
+}
+
 /*
  * Return true if the rwsem is owned by a reader.
  */
 static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
 {
-#ifdef CONFIG_DEBUG_RWSEMS
 	/*
 	 * Check the count to see if it is write-locked.
 	 */
@@ -194,11 +203,9 @@ static inline bool is_rwsem_reader_owned(struct rw_semaphore *sem)
 
 	if (count & RWSEM_WRITER_MASK)
 		return false;
-#endif
 	return rwsem_test_oflags(sem, RWSEM_READER_OWNED);
 }
 
-#ifdef CONFIG_DEBUG_RWSEMS
 /*
  * With CONFIG_DEBUG_RWSEMS configured, it will make sure that if there
  * is a task pointer in owner of a reader-owned rwsem, it will be the
@@ -266,15 +273,6 @@ static inline bool rwsem_write_trylock(struct rw_semaphore *sem)
 }
 
 /*
- * Return just the real task structure pointer of the owner
- */
-static inline struct task_struct *rwsem_owner(struct rw_semaphore *sem)
-{
-	return (struct task_struct *)
-		(atomic_long_read(&sem->owner) & ~RWSEM_OWNER_FLAGS_MASK);
-}
-
-/*
  * Return the real task structure pointer of the owner and the embedded
  * flags in the owner. pflags must be non-NULL.
  */