diff mbox series

[1/7] futex: abstract out futex_op_to_flags() helper

Message ID 20230712004705.316157-2-axboe@kernel.dk (mailing list archive)
State New
Headers show
Series Add io_uring futex/futexv support | expand

Commit Message

Jens Axboe July 12, 2023, 12:46 a.m. UTC 
Rather than needing to duplicate this for the io_uring hook of futexes,
abstract out a helper.

No functional changes intended in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 kernel/futex/futex.h    | 15 +++++++++++++++
 kernel/futex/syscalls.c | 11 ++---------
 2 files changed, 17 insertions(+), 9 deletions(-)

Comments

Peter Zijlstra July 12, 2023, 8:16 a.m. UTC | #1 
On Tue, Jul 11, 2023 at 06:46:59PM -0600, Jens Axboe wrote:
> Rather than needing to duplicate this for the io_uring hook of futexes,
> abstract out a helper.
> 
> No functional changes intended in this patch.
> 
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
>  kernel/futex/futex.h    | 15 +++++++++++++++
>  kernel/futex/syscalls.c | 11 ++---------
>  2 files changed, 17 insertions(+), 9 deletions(-)
> 
> diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
> index b5379c0e6d6d..d2949fca37d1 100644
> --- a/kernel/futex/futex.h
> +++ b/kernel/futex/futex.h
> @@ -291,4 +291,19 @@ extern int futex_unlock_pi(u32 __user *uaddr, unsigned int flags);
>  
>  extern int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int trylock);
>  
> +static inline bool futex_op_to_flags(int op, int cmd, unsigned int *flags)
> +{
	*flags = 0;

> +	if (!(op & FUTEX_PRIVATE_FLAG))
> +		*flags |= FLAGS_SHARED;
> +
> +	if (op & FUTEX_CLOCK_REALTIME) {
> +		*flags |= FLAGS_CLOCKRT;
> +		if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
> +		    cmd != FUTEX_LOCK_PI2)
> +			return false;
> +	}
> +
> +	return true;
> +}


> diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
> index a8074079b09e..75ca8c41cc94 100644
> --- a/kernel/futex/syscalls.c
> +++ b/kernel/futex/syscalls.c
> @@ -88,15 +88,8 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
>  	int cmd = op & FUTEX_CMD_MASK;
>  	unsigned int flags = 0;

and skip the initializer here.

>  
> -	if (!(op & FUTEX_PRIVATE_FLAG))
> -		flags |= FLAGS_SHARED;
> -
> -	if (op & FUTEX_CLOCK_REALTIME) {
> -		flags |= FLAGS_CLOCKRT;
> -		if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
> -		    cmd != FUTEX_LOCK_PI2)
> -			return -ENOSYS;
> -	}
> +	if (!futex_op_to_flags(op, cmd, &flags))
> +		return -ENOSYS;
>  

then the helper is more self sufficient and doesn't rely on the caller
to initialize the flags word.
Jens Axboe July 12, 2023, 2:59 p.m. UTC | #2 
On 7/12/23 2:16 AM, Peter Zijlstra wrote:
> On Tue, Jul 11, 2023 at 06:46:59PM -0600, Jens Axboe wrote:
>> Rather than needing to duplicate this for the io_uring hook of futexes,
>> abstract out a helper.
>>
>> No functional changes intended in this patch.
>>
>> Signed-off-by: Jens Axboe <axboe@kernel.dk>
>> ---
>>  kernel/futex/futex.h    | 15 +++++++++++++++
>>  kernel/futex/syscalls.c | 11 ++---------
>>  2 files changed, 17 insertions(+), 9 deletions(-)
>>
>> diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
>> index b5379c0e6d6d..d2949fca37d1 100644
>> --- a/kernel/futex/futex.h
>> +++ b/kernel/futex/futex.h
>> @@ -291,4 +291,19 @@ extern int futex_unlock_pi(u32 __user *uaddr, unsigned int flags);
>>  
>>  extern int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int trylock);
>>  
>> +static inline bool futex_op_to_flags(int op, int cmd, unsigned int *flags)
>> +{
> 	*flags = 0;
> 
>> +	if (!(op & FUTEX_PRIVATE_FLAG))
>> +		*flags |= FLAGS_SHARED;
>> +
>> +	if (op & FUTEX_CLOCK_REALTIME) {
>> +		*flags |= FLAGS_CLOCKRT;
>> +		if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
>> +		    cmd != FUTEX_LOCK_PI2)
>> +			return false;
>> +	}
>> +
>> +	return true;
>> +}
> 
> 
>> diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
>> index a8074079b09e..75ca8c41cc94 100644
>> --- a/kernel/futex/syscalls.c
>> +++ b/kernel/futex/syscalls.c
>> @@ -88,15 +88,8 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
>>  	int cmd = op & FUTEX_CMD_MASK;
>>  	unsigned int flags = 0;
> 
> and skip the initializer here.
> 
>>  
>> -	if (!(op & FUTEX_PRIVATE_FLAG))
>> -		flags |= FLAGS_SHARED;
>> -
>> -	if (op & FUTEX_CLOCK_REALTIME) {
>> -		flags |= FLAGS_CLOCKRT;
>> -		if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
>> -		    cmd != FUTEX_LOCK_PI2)
>> -			return -ENOSYS;
>> -	}
>> +	if (!futex_op_to_flags(op, cmd, &flags))
>> +		return -ENOSYS;
>>  
> 
> then the helper is more self sufficient and doesn't rely on the caller
> to initialize the flags word.

Good idea - done, thanks.
diff mbox series

Patch

diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
index b5379c0e6d6d..d2949fca37d1 100644
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -291,4 +291,19 @@  extern int futex_unlock_pi(u32 __user *uaddr, unsigned int flags);
 
 extern int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int trylock);
 
+static inline bool futex_op_to_flags(int op, int cmd, unsigned int *flags)
+{
+	if (!(op & FUTEX_PRIVATE_FLAG))
+		*flags |= FLAGS_SHARED;
+
+	if (op & FUTEX_CLOCK_REALTIME) {
+		*flags |= FLAGS_CLOCKRT;
+		if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
+		    cmd != FUTEX_LOCK_PI2)
+			return false;
+	}
+
+	return true;
+}
+
 #endif /* _FUTEX_H */
diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
index a8074079b09e..75ca8c41cc94 100644
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -88,15 +88,8 @@  long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 	int cmd = op & FUTEX_CMD_MASK;
 	unsigned int flags = 0;
 
-	if (!(op & FUTEX_PRIVATE_FLAG))
-		flags |= FLAGS_SHARED;
-
-	if (op & FUTEX_CLOCK_REALTIME) {
-		flags |= FLAGS_CLOCKRT;
-		if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
-		    cmd != FUTEX_LOCK_PI2)
-			return -ENOSYS;
-	}
+	if (!futex_op_to_flags(op, cmd, &flags))
+		return -ENOSYS;
 
 	switch (cmd) {
 	case FUTEX_WAIT: