From: "André Almeida" <andrealmeid@igalia.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com,
dvhart@infradead.org, dave@stgolabs.net,
Andrew Morton <akpm@linux-foundation.org>,
urezki@gmail.com, hch@infradead.org, lstoakes@gmail.com,
Arnd Bergmann <arnd@arndb.de>,
tglx@linutronix.de, linux-api@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
malteskarupke@web.de, axboe@kernel.dk
Subject: Re: [PATCH v2 01/14] futex: Clarify FUTEX2 flags
Date: Mon, 7 Aug 2023 20:51:42 -0300 [thread overview]
Message-ID: <3e73ae5e-8550-42a7-82de-bea1ca57fe1e@igalia.com> (raw)
In-Reply-To: <20230807123322.814039156@infradead.org>
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;
>
>
next prev parent reply other threads:[~2023-08-07 23:52 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-07 12:18 [PATCH v2 00/14] futex: More futex2 bits Peter Zijlstra
2023-08-07 12:18 ` [PATCH v2 01/14] futex: Clarify FUTEX2 flags Peter Zijlstra
2023-08-07 23:51 ` André Almeida [this message]
2023-08-07 12:18 ` [PATCH v2 02/14] futex: Extend the " Peter Zijlstra
2023-08-07 18:56 ` Thomas Gleixner
2023-08-08 0:02 ` André Almeida
2023-08-07 12:18 ` [PATCH v2 03/14] futex: Flag conversion Peter Zijlstra
2023-08-07 18:58 ` Thomas Gleixner
2023-08-08 0:52 ` André Almeida
2023-08-07 12:18 ` [PATCH v2 04/14] futex: Validate futex value against futex size Peter Zijlstra
2023-08-07 12:18 ` [PATCH v2 05/14] futex: Add sys_futex_wake() Peter Zijlstra
2023-08-07 19:00 ` Thomas Gleixner
2023-08-09 22:25 ` André Almeida
2023-08-10 12:13 ` Peter Zijlstra
2023-08-10 17:01 ` André Almeida
2023-08-07 12:18 ` [PATCH v2 06/14] futex: Add sys_futex_wait() Peter Zijlstra
2023-08-07 12:18 ` [PATCH v2 07/14] futex: Propagate flags into get_futex_key() Peter Zijlstra
2023-08-07 12:18 ` [PATCH v2 08/14] futex: Add flags2 argument to futex_requeue() Peter Zijlstra
2023-08-07 19:01 ` Thomas Gleixner
2023-08-07 12:18 ` [PATCH v2 09/14] futex: Add sys_futex_requeue() Peter Zijlstra
2023-08-07 19:05 ` Thomas Gleixner
2023-08-07 12:18 ` [PATCH v2 10/14] mm: Add vmalloc_huge_node() Peter Zijlstra
2023-08-07 12:18 ` [PATCH v2 11/14] futex: Implement FUTEX2_NUMA Peter Zijlstra
2023-08-07 21:11 ` Thomas Gleixner
2023-08-08 8:54 ` Peter Zijlstra
2023-08-08 9:12 ` Thomas Gleixner
2023-08-07 12:18 ` [PATCH v2 12/14] futex: Propagate flags into futex_get_value_locked() Peter Zijlstra
2023-08-07 21:12 ` Thomas Gleixner
2023-08-07 12:18 ` [PATCH v2 13/14] futex: Enable FUTEX2_{8,16} Peter Zijlstra
2023-08-07 21:15 ` Thomas Gleixner
2023-08-07 12:18 ` [PATCH v2 14/14] futex,selftests: Extend the futex selftests Peter Zijlstra
2023-08-08 20:32 ` [PATCH v2 00/14] futex: More futex2 bits Jens Axboe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3e73ae5e-8550-42a7-82de-bea1ca57fe1e@igalia.com \
--to=andrealmeid@igalia.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=axboe@kernel.dk \
--cc=dave@stgolabs.net \
--cc=dvhart@infradead.org \
--cc=hch@infradead.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lstoakes@gmail.com \
--cc=malteskarupke@web.de \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=urezki@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).