| Message ID | 20230807123322.814039156@infradead.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | futex: More futex2 bits | expand |
Hi Peter, thank you for your patches. Em 07/08/2023 09:18, Peter Zijlstra escreveu: > sys_futex_waitv() is part of the futex2 series (the first and only so > far) of syscalls and has a flags field per futex (as opposed to flags > being encoded in the futex op). > > This new flags field has a new namespace, which unfortunately isn't > super explicit. Notably it currently takes FUTEX_32 and > FUTEX_PRIVATE_FLAG. > > Introduce the FUTEX2 namespace to clarify this > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: André Almeida <andrealmeid@igalia.com> > --- > include/uapi/linux/futex.h | 16 +++++++++++++--- > kernel/futex/syscalls.c | 7 +++---- > 2 files changed, 16 insertions(+), 7 deletions(-) > > --- a/include/uapi/linux/futex.h > +++ b/include/uapi/linux/futex.h > @@ -44,10 +44,20 @@ > FUTEX_PRIVATE_FLAG) > > /* > - * Flags to specify the bit length of the futex word for futex2 syscalls. > - * Currently, only 32 is supported. > + * Flags for futex2 syscalls. > */ > -#define FUTEX_32 2 > + /* 0x00 */ > + /* 0x01 */ > +#define FUTEX2_SIZE_U32 0x02 > + /* 0x04 */ > + /* 0x08 */ > + /* 0x10 */ > + /* 0x20 */ > + /* 0x40 */ > +#define FUTEX2_PRIVATE FUTEX_PRIVATE_FLAG > + > +/* do not use */ > +#define FUTEX_32 FUTEX2_SIZE_U32 /* historical accident :-( */ > > /* > * Max numbers of elements in a futex_waitv array > --- a/kernel/futex/syscalls.c > +++ b/kernel/futex/syscalls.c > @@ -183,8 +183,7 @@ SYSCALL_DEFINE6(futex, u32 __user *, uad > return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3); > } > > -/* Mask of available flags for each futex in futex_waitv list */ > -#define FUTEXV_WAITER_MASK (FUTEX_32 | FUTEX_PRIVATE_FLAG) > +#define FUTEX2_VALID_MASK (FUTEX2_SIZE_U32 | FUTEX2_PRIVATE) > > /** > * futex_parse_waitv - Parse a waitv array from userspace > @@ -205,10 +204,10 @@ static int futex_parse_waitv(struct fute > if (copy_from_user(&aux, &uwaitv[i], sizeof(aux))) > return -EFAULT; > > - if ((aux.flags & ~FUTEXV_WAITER_MASK) || aux.__reserved) > + if ((aux.flags & ~FUTEX2_VALID_MASK) || aux.__reserved) > return -EINVAL; > > - if (!(aux.flags & FUTEX_32)) > + if (!(aux.flags & FUTEX2_SIZE_U32)) > return -EINVAL; > > futexv[i].w.flags = aux.flags; > >
--- a/include/uapi/linux/futex.h +++ b/include/uapi/linux/futex.h @@ -44,10 +44,20 @@ FUTEX_PRIVATE_FLAG) /* - * Flags to specify the bit length of the futex word for futex2 syscalls. - * Currently, only 32 is supported. + * Flags for futex2 syscalls. */ -#define FUTEX_32 2 + /* 0x00 */ + /* 0x01 */ +#define FUTEX2_SIZE_U32 0x02 + /* 0x04 */ + /* 0x08 */ + /* 0x10 */ + /* 0x20 */ + /* 0x40 */ +#define FUTEX2_PRIVATE FUTEX_PRIVATE_FLAG + +/* do not use */ +#define FUTEX_32 FUTEX2_SIZE_U32 /* historical accident :-( */ /* * Max numbers of elements in a futex_waitv array --- a/kernel/futex/syscalls.c +++ b/kernel/futex/syscalls.c @@ -183,8 +183,7 @@ SYSCALL_DEFINE6(futex, u32 __user *, uad return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3); } -/* Mask of available flags for each futex in futex_waitv list */ -#define FUTEXV_WAITER_MASK (FUTEX_32 | FUTEX_PRIVATE_FLAG) +#define FUTEX2_VALID_MASK (FUTEX2_SIZE_U32 | FUTEX2_PRIVATE) /** * futex_parse_waitv - Parse a waitv array from userspace @@ -205,10 +204,10 @@ static int futex_parse_waitv(struct fute if (copy_from_user(&aux, &uwaitv[i], sizeof(aux))) return -EFAULT; - if ((aux.flags & ~FUTEXV_WAITER_MASK) || aux.__reserved) + if ((aux.flags & ~FUTEX2_VALID_MASK) || aux.__reserved) return -EINVAL; - if (!(aux.flags & FUTEX_32)) + if (!(aux.flags & FUTEX2_SIZE_U32)) return -EINVAL; futexv[i].w.flags = aux.flags;