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From: David Howells <dhowells@redhat.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: dhowells@redhat.com,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Casey Schaufler <casey@schaufler-ca.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Nicolas Dichtel <nicolas.dichtel@6wind.com>,
	raven@themaw.net, Christian Brauner <christian@brauner.io>,
	keyrings@vger.kernel.org, USB list <linux-usb@vger.kernel.org>,
	linux-block <linux-block@vger.kernel.org>,
	LSM List <linux-security-module@vger.kernel.org>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 08/14] pipe: Allow buffers to be marked read-whole-or-error for notifications [ver #2]
Date: Thu, 07 Nov 2019 18:23:04 +0000	[thread overview]
Message-ID: <4649.1573150984@warthog.procyon.org.uk> (raw)
In-Reply-To: <CALCETrWszYm9=-WEgSbhmGc3DYCvY6q3W4Lezm6YtKnGtRs_5g@mail.gmail.com>

Andy Lutomirski <luto@kernel.org> wrote:

> > Allow a buffer to be marked such that read() must return the entire buffer
> > in one go or return ENOBUFS.  Multiple buffers can be amalgamated into a
> > single read, but a short read will occur if the next "whole" buffer won't
> > fit.
> >
> > This is useful for watch queue notifications to make sure we don't split a
> > notification across multiple reads, especially given that we need to
> > fabricate an overrun record under some circumstances - and that isn't in
> > the buffers.
> 
> Hmm.  I'm not totally in love with introducing a new error code like
> this for read(), especially if it could affect the kind of pipe that
> is bound to a file in a filesystem.  But maybe it's not a problem.

EMSGSIZE might be better?

David


WARNING: multiple messages have this Message-ID
From: David Howells <dhowells@redhat.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: dhowells@redhat.com,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Casey Schaufler <casey@schaufler-ca.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Nicolas Dichtel <nicolas.dichtel@6wind.com>,
	raven@themaw.net, Christian Brauner <christian@brauner.io>,
	keyrings@vger.kernel.org, USB list <linux-usb@vger.kernel.org>,
	linux-block <linux-block@vger.kernel.org>,
	LSM List <linux-security-module@vger.kernel.org>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 08/14] pipe: Allow buffers to be marked read-whole-or-error for notifications [ver #2
Date: Thu, 07 Nov 2019 18:23:04 +0000	[thread overview]
Message-ID: <4649.1573150984@warthog.procyon.org.uk> (raw)
In-Reply-To: <CALCETrWszYm9=-WEgSbhmGc3DYCvY6q3W4Lezm6YtKnGtRs_5g@mail.gmail.com>

Andy Lutomirski <luto@kernel.org> wrote:

> > Allow a buffer to be marked such that read() must return the entire buffer
> > in one go or return ENOBUFS.  Multiple buffers can be amalgamated into a
> > single read, but a short read will occur if the next "whole" buffer won't
> > fit.
> >
> > This is useful for watch queue notifications to make sure we don't split a
> > notification across multiple reads, especially given that we need to
> > fabricate an overrun record under some circumstances - and that isn't in
> > the buffers.
> 
> Hmm.  I'm not totally in love with introducing a new error code like
> this for read(), especially if it could affect the kind of pipe that
> is bound to a file in a filesystem.  But maybe it's not a problem.

EMSGSIZE might be better?

David

  parent reply	other threads:[~2019-11-07 18:24 UTC|newest]

Thread overview: 110+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07 13:35 [RFC PATCH 00/14] pipe: Keyrings, Block and USB " David Howells
2019-11-07 13:35 ` David Howells
2019-11-07 13:35 ` David Howells
2019-11-07 13:35 ` [RFC PATCH 01/14] uapi: General notification queue definitions " David Howells
2019-11-07 13:35   ` David Howells
2019-11-07 13:35   ` David Howells
2019-11-07 13:35 ` [RFC PATCH 02/14] security: Add hooks to rule on setting a watch " David Howells
2019-11-07 13:35   ` David Howells
2019-11-07 13:35   ` David Howells
2019-11-07 13:35 ` [RFC PATCH 03/14] security: Add a hook for the point of notification insertion " David Howells
2019-11-07 13:35   ` David Howells
2019-11-07 13:35   ` David Howells
2019-11-07 13:35 ` [RFC PATCH 04/14] pipe: Add O_NOTIFICATION_PIPE " David Howells
2019-11-07 13:35   ` David Howells
2019-11-07 13:35   ` David Howells
2019-11-07 18:16   ` Andy Lutomirski
2019-11-07 18:16     ` Andy Lutomirski
2019-11-07 18:48   ` David Howells
2019-11-08  5:06     ` Andy Lutomirski
2019-11-08  5:06       ` Andy Lutomirski
2019-11-08  6:42     ` David Howells
2019-11-07 13:36 ` [RFC PATCH 05/14] pipe: Add general notification queue support " David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36 ` [RFC PATCH 06/14] keys: Add a notification facility " David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36 ` [RFC PATCH 07/14] Add sample notification program " David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36 ` [RFC PATCH 08/14] pipe: Allow buffers to be marked read-whole-or-error for notifications " David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 18:15   ` Andy Lutomirski
2019-11-07 18:15     ` [RFC PATCH 08/14] pipe: Allow buffers to be marked read-whole-or-error for notifications [ver #2 Andy Lutomirski
2019-11-07 18:23   ` David Howells [this message]
2019-11-07 18:23     ` David Howells
2019-11-07 13:36 ` [RFC PATCH 09/14] pipe: Add notification lossage handling [ver #2] David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36 ` [RFC PATCH 10/14] Add a general, global device notification watch list " David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:36   ` David Howells
2019-11-07 13:37 ` [RFC PATCH 11/14] block: Add block layer notifications " David Howells
2019-11-07 13:37   ` David Howells
2019-11-07 13:37   ` David Howells
2019-11-07 13:37 ` [RFC PATCH 12/14] usb: Add USB subsystem " David Howells
2019-11-07 13:37   ` David Howells
2019-11-07 13:37   ` David Howells
2019-11-07 13:37 ` [RFC PATCH 13/14] selinux: Implement the watch_key security hook " David Howells
2019-11-07 13:37   ` David Howells
2019-11-07 13:37   ` David Howells
2019-11-07 13:37 ` [RFC PATCH 14/14] smack: Implement the watch_key and post_notification hooks " David Howells
2019-11-07 13:37   ` David Howells
2019-11-07 13:37   ` David Howells
2019-11-07 17:16 ` [RFC PATCH 05/14] pipe: Add general notification queue support " David Howells
2020-01-15 13:30 [RFC PATCH 00/14] pipe: Keyrings, Block and USB notifications [ver #3] David Howells
2020-01-15 13:30 ` David Howells
2020-01-15 13:30 ` David Howells
2020-01-15 13:30 ` [RFC PATCH 01/14] uapi: General notification queue definitions " David Howells
2020-01-15 13:30   ` David Howells
2020-01-15 13:30   ` David Howells
2020-01-15 13:30 ` [RFC PATCH 02/14] security: Add hooks to rule on setting a watch " David Howells
2020-01-15 13:30   ` David Howells
2020-01-15 13:30   ` David Howells
2020-01-15 13:31 ` [RFC PATCH 03/14] security: Add a hook for the point of notification insertion " David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31 ` [RFC PATCH 04/14] pipe: Add O_NOTIFICATION_PIPE " David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31 ` [RFC PATCH 05/14] pipe: Add general notification queue support " David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31 ` [RFC PATCH 06/14] keys: Add a notification facility " David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31 ` [RFC PATCH 07/14] Add sample notification program " David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31   ` David Howells
2020-01-26 15:47   ` Guenter Roeck
2020-01-26 15:47     ` Guenter Roeck
2020-01-26 15:47     ` Guenter Roeck
2020-01-15 13:31 ` [RFC PATCH 08/14] pipe: Allow buffers to be marked read-whole-or-error for notifications " David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31 ` [RFC PATCH 09/14] pipe: Add notification lossage handling " David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:31   ` David Howells
2020-01-15 13:32 ` [RFC PATCH 10/14] Add a general, global device notification watch list " David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 13:32 ` [RFC PATCH 11/14] block: Add block layer notifications " David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 13:32 ` [RFC PATCH 12/14] usb: Add USB subsystem " David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 13:32 ` [RFC PATCH 13/14] selinux: Implement the watch_key security hook " David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 13:32 ` [RFC PATCH 14/14] smack: Implement the watch_key and post_notification hooks " David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 13:32   ` David Howells
2020-01-15 20:10 ` [RFC PATCH 00/14] pipe: Keyrings, Block and USB notifications " Linus Torvalds
2020-01-15 20:10   ` Linus Torvalds
2020-02-11  0:56   ` Andres Freund
2020-02-11  0:56     ` Andres Freund
2020-01-15 21:07 ` David Howells
2020-01-15 21:07   ` David Howells

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