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Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH 1/7] futex: abstract out futex_op_to_flags() helper Content-Language: en-US To: Peter Zijlstra Cc: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com References: <20230712004705.316157-1-axboe@kernel.dk> <20230712004705.316157-2-axboe@kernel.dk> <20230712081617.GB3100107@hirez.programming.kicks-ass.net> From: Jens Axboe In-Reply-To: <20230712081617.GB3100107@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org 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 >> --- >> 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