From: Jens Axboe <[email protected]>
To: Peter Zijlstra <[email protected]>
Cc: [email protected], [email protected],
[email protected], [email protected]
Subject: Re: [PATCH 1/7] futex: abstract out futex_op_to_flags() helper
Date: Wed, 12 Jul 2023 08:59:47 -0600 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
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 <[email protected]>
>> ---
>> 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.
--
Jens Axboe
next prev parent reply other threads:[~2023-07-12 15:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-12 0:46 [PATCHSET 0/7] Add io_uring futex/futexv support Jens Axboe
2023-07-12 0:46 ` [PATCH 1/7] futex: abstract out futex_op_to_flags() helper Jens Axboe
2023-07-12 8:16 ` Peter Zijlstra
2023-07-12 14:59 ` Jens Axboe [this message]
2023-07-12 0:47 ` [PATCH 2/7] futex: factor out the futex wake handling Jens Axboe
2023-07-12 8:58 ` Peter Zijlstra
2023-07-12 15:02 ` Jens Axboe
2023-07-12 0:47 ` [PATCH 3/7] io_uring: add support for futex wake and wait Jens Axboe
2023-07-12 8:51 ` Peter Zijlstra
2023-07-12 15:05 ` Jens Axboe
2023-07-12 0:47 ` [PATCH 4/7] futex: add wake_data to struct futex_q Jens Axboe
2023-07-12 0:47 ` [PATCH 5/7] futex: make futex_parse_waitv() available as a helper Jens Axboe
2023-07-12 9:25 ` Peter Zijlstra
2023-07-12 15:06 ` Jens Axboe
2023-07-12 0:47 ` [PATCH 6/7] futex: make the vectored futex operations available Jens Axboe
2023-07-12 0:47 ` [PATCH 7/7] io_uring: add futex waitv Jens Axboe
2023-07-12 9:31 ` Peter Zijlstra
2023-07-12 15:10 ` Jens Axboe
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