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From: Matthew Wilcox <willy@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexey Gladkov <legion@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Christian Brauner <brauner@kernel.org>,
	Iurii Zaikin <yzaikin@google.com>,
	Kees Cook <keescook@chromium.org>,
	Linux Containers <containers@lists.linux.dev>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Vasily Averin <vvs@virtuozzo.com>
Subject: Re: [RFC PATCH 1/4] sysctl: API extension for handling sysctl
Date: Wed, 1 Jun 2022 20:25:20 +0100	[thread overview]
Message-ID: <Ype9ILKm+8WLOq9W@casper.infradead.org> (raw)
In-Reply-To: <CAHk-=wiTtYMia0FR4h7_nV2RZ5pq=wR-7oMMK3o8o=EgAxMsmg@mail.gmail.com>

On Wed, Jun 01, 2022 at 12:23:06PM -0700, Linus Torvalds wrote:
> On Wed, Jun 1, 2022 at 12:19 PM Matthew Wilcox <willy@infradead.org> wrote:
> >
> > Why not pass the iocb in ->read and ->write?  We're still regretting not
> > doing that with file_operations.
> 
> No, all the actual "io" is done by the caller.
> 
> There is no way in hell I want the sysctl callbacks to actually
> possibly do user space accesses etc.
> 
> They get a kernel buffer that has already been set up. There is no
> iocb or iovec left for them.

I wasn't suggesting the iovec.  Just the iocb, instead of passing in the
ki_filp and the ki_pos.

> (That also means that they can take whatever locks they need,
> including spinlocks, because there's not going to be any random user
> accesses or complex pipe buffer lookups or whatever).
> 
>                 Linus

  reply	other threads:[~2022-06-01 19:25 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-14 18:18 [PATCH v4 0/2] ipc: Store mq and ipc sysctls in the ipc namespace Alexey Gladkov
2022-02-14 18:18 ` [PATCH v4 1/2] ipc: Store mqueue " Alexey Gladkov
2022-02-14 18:18 ` [PATCH v4 2/2] ipc: Store ipc " Alexey Gladkov
2022-03-23 20:24 ` [GIT PULL] ipc: Bind to the ipc namespace at open time Eric W. Biederman
2022-03-24 18:12   ` Linus Torvalds
2022-03-24 21:48     ` Eric W. Biederman
2022-03-24 22:16       ` Linus Torvalds
2022-03-25 12:10     ` Alexey Gladkov
2022-04-22 12:53     ` [PATCH v1 0/4] ipc: Remove extra1 field abuse to pass ipc namespace Alexey Gladkov
2022-04-22 12:53       ` [PATCH v1 1/4] " Alexey Gladkov
2022-05-02 16:07         ` Eric W. Biederman
2022-04-22 12:53       ` [PATCH v1 2/4] ipc: Use proper " Alexey Gladkov
2022-05-02 16:09         ` Eric W. Biederman
2022-05-03 13:39           ` Alexey Gladkov
2022-05-03 13:39             ` [PATCH v2 1/4] ipc: Use the same namespace to modify and validate Alexey Gladkov
2022-05-03 13:39             ` [PATCH v2 2/4] ipc: Remove extra1 field abuse to pass ipc namespace Alexey Gladkov
2022-05-03 13:39             ` [PATCH v2 3/4] ipc: Check permissions for checkpoint_restart sysctls at open time Alexey Gladkov
2022-05-03 13:39             ` [PATCH v2 4/4] ipc: Remove extra braces Alexey Gladkov
2022-04-22 12:53       ` [PATCH v1 3/4] ipc: Check permissions for checkpoint_restart sysctls at open time Alexey Gladkov
2022-04-22 12:53       ` [PATCH v1 4/4] ipc: Remove extra braces Alexey Gladkov
2022-04-22 20:44       ` [PATCH v1 0/4] ipc: Remove extra1 field abuse to pass ipc namespace Linus Torvalds
2022-05-04  3:42         ` Philip Rhoades
2022-06-01 13:20         ` [RFC PATCH 0/4] API extension for handling sysctl Alexey Gladkov
2022-06-01 13:20           ` [RFC PATCH 1/4] sysctl: " Alexey Gladkov
2022-06-01 19:19             ` Matthew Wilcox
2022-06-01 19:23               ` Linus Torvalds
2022-06-01 19:25                 ` Matthew Wilcox [this message]
2022-06-01 19:31                   ` Linus Torvalds
2022-06-01 19:32               ` Alexey Gladkov
2022-06-01 13:20           ` [RFC PATCH 2/4] sysctl: ipc: Do not use dynamic memory Alexey Gladkov
2022-06-01 16:45             ` Linus Torvalds
2022-06-01 18:24               ` Alexey Gladkov
2022-06-01 18:34                 ` Linus Torvalds
2022-06-01 19:05                   ` Alexey Gladkov
2022-06-09 18:51                   ` Luis Chamberlain
2022-06-01 13:20           ` [RFC PATCH 3/4] sysctl: userns: " Alexey Gladkov
2022-06-01 13:20           ` [RFC PATCH 4/4] sysctl: mqueue: " Alexey Gladkov
2022-06-09 16:45           ` [RFC PATCH 0/4] API extension for handling sysctl Luis Chamberlain

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