From: Shuah Khan <skhan@linuxfoundation.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: corbet@lwn.net, keescook@chromium.org,
gregkh@linuxfoundation.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, skhan@linuxfoundation.org
Subject: Re: [PATCH 01/13] seqnum_ops: Introduce Sequence Number Ops
Date: Wed, 11 Nov 2020 10:34:05 -0700 [thread overview]
Message-ID: <3fccb8d5-825a-a283-7b7e-6193e0c90237@linuxfoundation.org> (raw)
In-Reply-To: <20201111160411.GF2628@hirez.programming.kicks-ass.net>
On 11/11/20 9:04 AM, Peter Zijlstra wrote:
> On Wed, Nov 11, 2020 at 08:56:49AM -0700, Shuah Khan wrote:
>
>> Why would you say no to read and inc?
>
> Because they don't guarantee uniqueness (bar wrapping), which is the
> only reason to use an atomic to begin with.
>
Thanks for the explanation. I see what you are saying.
Not sure what to make of the 6080 atomic_read()s and 3413
atomic_inc()s, some of which might be assuming uniqueness
guarantee.
As far as the sequence number api is concerned, I am with you on
not exposing read() and inc().
inc()s can just map to inc_return().
For read():
In the context of up counters, there is a definitely a need for get
current value type interface that guarantees uniqueness - similar to
inc_return without actually incrementing.
I will work on v2 based on the discussion.
thanks,
-- Shuah
next prev parent reply other threads:[~2020-11-11 17:34 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-10 19:53 [PATCH 00/13] Introduce seqnum_ops Shuah Khan
2020-11-10 19:53 ` [PATCH 01/13] seqnum_ops: Introduce Sequence Number Ops Shuah Khan
2020-11-10 20:41 ` Greg KH
2020-11-10 20:43 ` Greg KH
2020-11-11 0:18 ` Kees Cook
2020-11-11 19:23 ` Shuah Khan
2020-11-12 12:36 ` Matthew Wilcox
2020-11-12 16:17 ` Shuah Khan
2020-11-12 16:45 ` Greg KH
2020-11-12 16:59 ` Shuah Khan
2020-11-12 21:27 ` Shuah Khan
2020-11-17 12:27 ` Peter Zijlstra
2020-11-10 21:03 ` Matthew Wilcox
2020-11-10 22:58 ` Shuah Khan
2020-11-11 0:20 ` Kees Cook
2020-11-11 15:42 ` Shuah Khan
2020-11-11 8:23 ` Peter Zijlstra
2020-11-11 15:56 ` Shuah Khan
2020-11-11 16:04 ` Peter Zijlstra
2020-11-11 17:34 ` Shuah Khan [this message]
2020-11-11 17:50 ` Peter Zijlstra
2020-11-11 18:28 ` Shuah Khan
2020-11-11 20:15 ` Peter Zijlstra
2020-11-12 13:29 ` Greg KH
2020-11-10 19:53 ` [PATCH 02/13] selftests:lib:test_seqnum_ops: add new test for seqnum_ops Shuah Khan
2020-11-10 19:53 ` [PATCH 03/13] drivers/acpi: convert seqno seqnum_ops Shuah Khan
2020-11-10 19:53 ` [PATCH 04/13] drivers/acpi/apei: convert seqno to seqnum_ops Shuah Khan
2020-11-10 19:53 ` [PATCH 05/13] drivers/base/test/test_async_driver_probe: convert to use seqnum_ops Shuah Khan
2020-11-10 19:53 ` [PATCH 06/13] drivers/char/ipmi: convert stats " Shuah Khan
2020-11-10 19:53 ` [PATCH 07/13] drivers/edac: convert pci counters to seqnum_ops Shuah Khan
2020-11-10 19:53 ` [PATCH 08/13] drivers/oprofile: convert stats to use seqnum_ops Shuah Khan
2020-11-10 19:53 ` [PATCH 09/13] drivers/staging/rtl8723bs: " Shuah Khan
2020-11-10 19:53 ` [PATCH 10/13] usb: usbip/vhci: convert seqno to seqnum_ops Shuah Khan
2020-11-10 19:53 ` [PATCH 11/13] drivers/staging/rtl8188eu: convert stats to use seqnum_ops Shuah Khan
2020-11-10 19:53 ` [PATCH 12/13] drivers/staging/unisys/visorhba: " Shuah Khan
2020-11-10 20:42 ` Greg KH
2020-11-10 21:02 ` Shuah Khan
2020-11-10 19:53 ` [PATCH 13/13] security/integrity/ima: converts stats to seqnum_ops Shuah Khan
2020-11-10 20:44 ` [PATCH 00/13] Introduce seqnum_ops Alan Stern
2020-11-10 22:42 ` Shuah Khan
2020-11-11 4:33 ` Matthew Wilcox
2020-11-11 16:03 ` Shuah Khan
2020-11-11 16:41 ` Matthew Wilcox
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