From: Greg KH <gregkh@linuxfoundation.org>
To: Shuah Khan <skhan@linuxfoundation.org>
Cc: corbet@lwn.net, peterz@infradead.org, keescook@chromium.org,
rafael@kernel.org, lenb@kernel.org, james.morse@arm.com,
tony.luck@intel.com, bp@alien8.de, devel@driverdev.osuosl.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-acpi@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v3 1/7] seqnum_ops: Introduce Sequence Number Ops
Date: Fri, 5 Feb 2021 10:58:36 +0100 [thread overview]
Message-ID: <YB0WzBnLd+OcpxEE@kroah.com> (raw)
In-Reply-To: <23f6347a7bb9f902babe7351f71b23644035673d.1612314468.git.skhan@linuxfoundation.org>
On Wed, Feb 03, 2021 at 11:11:57AM -0700, Shuah Khan wrote:
> +static inline u32 seqnum32_inc(struct seqnum32 *seq)
> +{
> + atomic_t val = ATOMIC_INIT(seq->seqnum);
> +
> + seq->seqnum = (u32) atomic_inc_return(&val);
> + if (seq->seqnum >= UINT_MAX)
> + pr_info("Sequence Number overflow %u detected\n",
> + seq->seqnum);
> + return seq->seqnum;
As Peter points out, this is doing doing what you think it is doing :(
Why do you not just have seq->seqnum be a real atomic variable? Trying
to switch to/from one like this does not work as there is no
"atomic-ness" happening here at all.
Oh, and checkpatch should have complained about the extra ' ' in your
cast :)
thanks,
greg k-h
next prev parent reply other threads:[~2021-02-06 0:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 18:11 [PATCH v3 0/7] Introduce Sequence Number Ops Shuah Khan
2021-02-03 18:11 ` [PATCH v3 1/7] seqnum_ops: " Shuah Khan
2021-02-04 9:20 ` Peter Zijlstra
2021-02-05 9:58 ` Greg KH [this message]
2021-02-05 20:03 ` Shuah Khan
2021-02-05 22:16 ` Luck, Tony
2021-02-08 3:55 ` Randy Dunlap
2021-02-03 18:11 ` [PATCH v3 2/7] selftests: lib:test_seqnum_ops: add new test for seqnum_ops Shuah Khan
2021-02-03 18:11 ` [PATCH v3 3/7] drivers/acpi: convert seqno to use seqnum_ops Shuah Khan
2021-02-04 14:01 ` Rafael J. Wysocki
2021-02-03 18:12 ` [PATCH v3 4/7] drivers/acpi/apei: convert seqno to seqnum_ops Shuah Khan
2021-02-03 18:12 ` [PATCH v3 5/7] drivers/staging/rtl8723bs: convert event_seq to use seqnum_ops Shuah Khan
2021-02-03 18:12 ` [PATCH v3 6/7] drivers/staging/rtl8188eu: " Shuah Khan
2021-02-03 18:12 ` [PATCH v3 7/7] kobject: convert uevent_seqnum to seqnum_ops Shuah Khan
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