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From: Kees Cook <keescook@chromium.org>
To: Shuah Khan <skhan@linuxfoundation.org>
Cc: corbet@lwn.net, gregkh@linuxfoundation.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 01/11] counters: Introduce counter_atomic* counters
Date: Wed, 7 Oct 2020 13:30:54 -0700	[thread overview]
Message-ID: <202010071329.90E96DC2@keescook> (raw)
In-Reply-To: <f0939f9d-d60f-7a97-31bd-e527c79ce284@linuxfoundation.org>

On Wed, Oct 07, 2020 at 01:26:53PM -0600, Shuah Khan wrote:
> On 10/7/20 12:11 PM, Kees Cook wrote:
> > My instinct is to say leave it "int" and adjust documentation, which is
> > the least disruptive, but I am enticed by the desire to make sure a
> > counter doesn't "misbehave" and go negative when the usage wants it
> > always positive.
> > 
> 
> I would recommend leaving it as "int". Changing the API to unsigned has
> other ramifications and cascading changes.
> 
> My quick search shows me there are 612 atomic_inc_return usages and
> 14 out of them are forcing the return type from int to u32.
> 
> For atomic_read the numbers are 51 out of 5833 forcing u32. We have
> couple of options:
> 
> 1. Update the documentation since we have more cases where
>    int is just fine.
> 2. Add counter_atomic32_inc_return_u32() variant to cover these few
>    cases that are forcing the return.
> 
> I recommend going with option 1 with Documentation update and add
> option 2 when we convert one of these 60+.

Agreed: 1 seems best, and then later 2 if it feels justified. :)

-- 
Kees Cook

  reply	other threads:[~2020-10-07 20:31 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-06 20:44 [PATCH v2 00/11] Introduce Simple atomic counters Shuah Khan
2020-10-06 20:44 ` [PATCH v2 01/11] counters: Introduce counter_atomic* counters Shuah Khan
2020-10-07  9:04   ` Greg KH
2020-10-08 17:18     ` Shuah Khan
2020-10-07 18:11   ` Kees Cook
2020-10-07 19:26     ` Shuah Khan
2020-10-07 20:30       ` Kees Cook [this message]
2020-10-06 20:44 ` [PATCH v2 02/11] selftests:lib:test_counters: add new test for counters Shuah Khan
2020-10-07 18:12   ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 03/11] drivers/base: convert deferred_trigger_count and probe_count to counter_atomic32 Shuah Khan
2020-10-07 18:13   ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 04/11] drivers/base/devcoredump: convert devcd_count " Shuah Khan
2020-10-07 18:15   ` Kees Cook
2020-10-07 19:33     ` Shuah Khan
2020-10-07 19:38       ` Johannes Berg
2020-10-07 19:59         ` Shuah Khan
2020-10-07 20:43         ` Kees Cook
2020-10-08  6:42           ` Johannes Berg
2020-10-08  7:37             ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 05/11] drivers/acpi: convert seqno counter_atomic32 Shuah Khan
2020-10-07 18:16   ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 06/11] drivers/acpi/apei: " Shuah Khan
2020-10-07 18:17   ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 07/11] drivers/android/binder: convert stats, transaction_log to counter_atomic32 Shuah Khan
2020-10-07 18:18   ` Kees Cook
2020-10-09 12:39   ` Christian Brauner
2020-10-06 20:44 ` [PATCH v2 08/11] drivers/base/test/test_async_driver_probe: convert to use counter_atomic32 Shuah Khan
2020-10-07 18:20   ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 09/11] drivers/char/ipmi: convert stats " Shuah Khan
2020-10-07 18:21   ` Kees Cook
2020-10-06 20:44 ` [PATCH v2 10/11] drivers/misc/vmw_vmci: convert num guest devices counter to counter_atomic32 Shuah Khan
2020-10-07 18:27   ` Kees Cook
2020-10-08 17:12     ` Shuah Khan
2020-10-06 20:44 ` [PATCH v2 11/11] drivers/edac: convert pci counters " Shuah Khan
2020-10-07 18:28   ` Kees Cook
2020-10-07 18:30 ` [PATCH v2 00/11] Introduce Simple atomic counters Kees Cook

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