From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: thierry.reding@gmail.com, joro@8bytes.org, krzk@kernel.org,
vdumpa@nvidia.com, jonathanh@nvidia.com,
linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] iommu/tegra-smmu: Rework .probe_device and .attach_dev
Date: Tue, 29 Sep 2020 23:13:52 -0700 [thread overview]
Message-ID: <20200930061351.GA16460@Asurada-Nvidia> (raw)
In-Reply-To: <b74f96cf-0edc-c7f2-3a0e-2a4fe51e3b2e@gmail.com>
On Wed, Sep 30, 2020 at 09:10:38AM +0300, Dmitry Osipenko wrote:
> 30.09.2020 08:49, Nicolin Chen пишет:
> > On Wed, Sep 30, 2020 at 08:11:52AM +0300, Dmitry Osipenko wrote:
> >> 30.09.2020 03:30, Nicolin Chen пишет:
> >>> + /* An invalid mc pointer means mc and smmu drivers are not ready */
> >>> + if (IS_ERR_OR_NULL(mc))
> >>
> >> tegra_get_memory_controller() doesn't return NULL.
> >
> > Well, I don't want to assume that it'd do that forever, and the
> > NULL check of IS_ERR_OR_NULL is marked "unlikely" so it doesn't
> > hurt to have.
> >
>
> I don't see any reasons why it won't do that forever.
>
> Secondly, public function can't be changed randomly without updating all
> the callers.
>
> Hence there is no need to handle cases that can't ever happen and it
> hurts readability of the code + original error code is missed.
I don't quite understand why an extra "_OR_NULL" would hurt
readability....but I'd take a step back and use IS_ERR().
WARNING: multiple messages have this Message-ID (diff)
From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
krzk@kernel.org, jonathanh@nvidia.com, thierry.reding@gmail.com,
linux-tegra@vger.kernel.org
Subject: Re: [PATCH v2 2/3] iommu/tegra-smmu: Rework .probe_device and .attach_dev
Date: Tue, 29 Sep 2020 23:13:52 -0700 [thread overview]
Message-ID: <20200930061351.GA16460@Asurada-Nvidia> (raw)
In-Reply-To: <b74f96cf-0edc-c7f2-3a0e-2a4fe51e3b2e@gmail.com>
On Wed, Sep 30, 2020 at 09:10:38AM +0300, Dmitry Osipenko wrote:
> 30.09.2020 08:49, Nicolin Chen пишет:
> > On Wed, Sep 30, 2020 at 08:11:52AM +0300, Dmitry Osipenko wrote:
> >> 30.09.2020 03:30, Nicolin Chen пишет:
> >>> + /* An invalid mc pointer means mc and smmu drivers are not ready */
> >>> + if (IS_ERR_OR_NULL(mc))
> >>
> >> tegra_get_memory_controller() doesn't return NULL.
> >
> > Well, I don't want to assume that it'd do that forever, and the
> > NULL check of IS_ERR_OR_NULL is marked "unlikely" so it doesn't
> > hurt to have.
> >
>
> I don't see any reasons why it won't do that forever.
>
> Secondly, public function can't be changed randomly without updating all
> the callers.
>
> Hence there is no need to handle cases that can't ever happen and it
> hurts readability of the code + original error code is missed.
I don't quite understand why an extra "_OR_NULL" would hurt
readability....but I'd take a step back and use IS_ERR().
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next prev parent reply other threads:[~2020-09-30 6:19 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 0:30 [PATCH v2 0/3] iommu/tegra-smmu: Add PCI support Nicolin Chen
2020-09-30 0:30 ` Nicolin Chen
2020-09-30 0:30 ` [PATCH v2 1/3] memory: tegra: Add helper function tegra_get_memory_controller Nicolin Chen
2020-09-30 0:30 ` Nicolin Chen
2020-09-30 5:12 ` Dmitry Osipenko
2020-09-30 5:12 ` Dmitry Osipenko
2020-09-30 5:44 ` Nicolin Chen
2020-09-30 5:44 ` Nicolin Chen
2020-09-30 6:32 ` Dmitry Osipenko
2020-09-30 6:32 ` Dmitry Osipenko
2020-09-30 6:38 ` Nicolin Chen
2020-09-30 6:38 ` Nicolin Chen
2020-09-30 7:31 ` Dmitry Osipenko
2020-09-30 7:31 ` Dmitry Osipenko
2020-09-30 7:21 ` Krzysztof Kozlowski
2020-09-30 7:21 ` Krzysztof Kozlowski
2020-09-30 7:25 ` Nicolin Chen
2020-09-30 7:25 ` Nicolin Chen
2020-09-30 7:50 ` Krzysztof Kozlowski
2020-09-30 7:50 ` Krzysztof Kozlowski
2020-09-30 0:30 ` [PATCH v2 2/3] iommu/tegra-smmu: Rework .probe_device and .attach_dev Nicolin Chen
2020-09-30 0:30 ` Nicolin Chen
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:20 ` Dmitry Osipenko
2020-09-30 5:20 ` Dmitry Osipenko
2020-09-30 5:50 ` Nicolin Chen
2020-09-30 5:50 ` Nicolin Chen
2020-09-30 6:34 ` Nicolin Chen
2020-09-30 6:34 ` Nicolin Chen
2020-09-30 5:11 ` Dmitry Osipenko
2020-09-30 5:11 ` Dmitry Osipenko
2020-09-30 5:49 ` Nicolin Chen
2020-09-30 5:49 ` Nicolin Chen
2020-09-30 6:10 ` Dmitry Osipenko
2020-09-30 6:10 ` Dmitry Osipenko
2020-09-30 6:13 ` Nicolin Chen [this message]
2020-09-30 6:13 ` Nicolin Chen
2020-09-30 6:33 ` Dmitry Osipenko
2020-09-30 6:33 ` Dmitry Osipenko
2020-09-30 5:24 ` Dmitry Osipenko
2020-09-30 5:24 ` Dmitry Osipenko
2020-09-30 5:39 ` Nicolin Chen
2020-09-30 5:39 ` Nicolin Chen
2020-09-30 5:48 ` Dmitry Osipenko
2020-09-30 5:48 ` Dmitry Osipenko
2020-09-30 5:39 ` Dmitry Osipenko
2020-09-30 5:39 ` Dmitry Osipenko
2020-09-30 5:41 ` Nicolin Chen
2020-09-30 5:41 ` Nicolin Chen
2020-09-30 5:59 ` Dmitry Osipenko
2020-09-30 5:59 ` Dmitry Osipenko
2020-09-30 6:19 ` Nicolin Chen
2020-09-30 6:19 ` Nicolin Chen
2020-09-30 0:30 ` [PATCH v2 3/3] iommu/tegra-smmu: Add PCI support Nicolin Chen
2020-09-30 0:30 ` Nicolin Chen
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:28 ` Nicolin Chen
2020-09-30 5:28 ` Nicolin Chen
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:29 ` Nicolin Chen
2020-09-30 5:29 ` Nicolin Chen
2020-09-30 5:58 ` Dmitry Osipenko
2020-09-30 5:58 ` Dmitry Osipenko
2020-09-30 7:16 ` Nicolin Chen
2020-09-30 7:16 ` Nicolin Chen
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:10 ` Dmitry Osipenko
2020-09-30 5:34 ` Nicolin Chen
2020-09-30 5:34 ` Nicolin Chen
2020-09-30 6:01 ` Dmitry Osipenko
2020-09-30 6:01 ` Dmitry Osipenko
2020-09-30 7:12 ` Nicolin Chen
2020-09-30 7:12 ` Nicolin Chen
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