All of lore.kernel.org
 help / color / mirror / Atom feed
From: Nicolin Chen <nicolinc@nvidia.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: <thierry.reding@gmail.com>, <joro@8bytes.org>, <will@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 v8 6/6] iommu/tegra-smmu: Add pagetable mappings to debugfs
Date: Thu, 9 Dec 2021 11:51:29 -0800	[thread overview]
Message-ID: <20211209195128.GA35526@Asurada-Nvidia> (raw)
In-Reply-To: <97a32c9a-2ec7-6579-7d8d-026d6f820a3e@gmail.com>

On Thu, Dec 09, 2021 at 10:40:42PM +0300, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
> 
> 
> 09.12.2021 22:32, Nicolin Chen пишет:
> > On Thu, Dec 09, 2021 at 05:47:18PM +0300, Dmitry Osipenko wrote:
> >> External email: Use caution opening links or attachments
> >>
> >>
> >> 09.12.2021 10:38, Nicolin Chen пишет:
> >>> @@ -545,6 +719,15 @@ static void tegra_smmu_detach_as(struct tegra_smmu *smmu,
> >>>               if (group->swgrp != swgrp)
> >>>                       continue;
> >>>               group->as = NULL;
> >>> +
> >>> +             if (smmu->debugfs_mappings) {
> >> Do we really need this check?
> >>
> >> Looks like all debugfs_create_dir() usages in this driver are incorrect,
> >> that function never returns NULL. Please fix this.
> > debugfs_create_dir returns ERR_PTR on failure. So here should be
> > to check !IS_ERR. Thanks for pointing it out!
> >
> 
> All debugfs functions handle IS_ERR(). GregKH removes all such checks
> all over the kernel. So the check shouldn't be needed at all, please
> remove it if it's unneeded or prove that it's needed.

debugfs_create_file can handle a NULL parent, but not ERR_PTR one,
and then it puts the new node under the root. So either passing an
ERR_PTR parent or creating orphan nodes here doesn't sound good...

WARNING: multiple messages have this Message-ID (diff)
From: Nicolin Chen via iommu <iommu@lists.linux-foundation.org>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	jonathanh@nvidia.com, thierry.reding@gmail.com,
	linux-tegra@vger.kernel.org, will@kernel.org
Subject: Re: [PATCH v8 6/6] iommu/tegra-smmu: Add pagetable mappings to debugfs
Date: Thu, 9 Dec 2021 11:51:29 -0800	[thread overview]
Message-ID: <20211209195128.GA35526@Asurada-Nvidia> (raw)
In-Reply-To: <97a32c9a-2ec7-6579-7d8d-026d6f820a3e@gmail.com>

On Thu, Dec 09, 2021 at 10:40:42PM +0300, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
> 
> 
> 09.12.2021 22:32, Nicolin Chen пишет:
> > On Thu, Dec 09, 2021 at 05:47:18PM +0300, Dmitry Osipenko wrote:
> >> External email: Use caution opening links or attachments
> >>
> >>
> >> 09.12.2021 10:38, Nicolin Chen пишет:
> >>> @@ -545,6 +719,15 @@ static void tegra_smmu_detach_as(struct tegra_smmu *smmu,
> >>>               if (group->swgrp != swgrp)
> >>>                       continue;
> >>>               group->as = NULL;
> >>> +
> >>> +             if (smmu->debugfs_mappings) {
> >> Do we really need this check?
> >>
> >> Looks like all debugfs_create_dir() usages in this driver are incorrect,
> >> that function never returns NULL. Please fix this.
> > debugfs_create_dir returns ERR_PTR on failure. So here should be
> > to check !IS_ERR. Thanks for pointing it out!
> >
> 
> All debugfs functions handle IS_ERR(). GregKH removes all such checks
> all over the kernel. So the check shouldn't be needed at all, please
> remove it if it's unneeded or prove that it's needed.

debugfs_create_file can handle a NULL parent, but not ERR_PTR one,
and then it puts the new node under the root. So either passing an
ERR_PTR parent or creating orphan nodes here doesn't sound good...
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2021-12-09 19:51 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-09  7:38 [PATCH v8 0/6] iommu/tegra-smmu: Add pagetable mappings to debugfs Nicolin Chen
2021-12-09  7:38 ` Nicolin Chen via iommu
2021-12-09  7:38 ` [PATCH v8 1/6] iommu/tegra-smmu: Rename struct iommu_group *group to *grp Nicolin Chen
2021-12-09  7:38   ` Nicolin Chen via iommu
2021-12-09  7:38 ` [PATCH v8 2/6] iommu/tegra-smmu: Rename tegra_smmu_find_group to tegra_smmu_find_group_soc Nicolin Chen
2021-12-09  7:38   ` Nicolin Chen via iommu
2021-12-09  7:38 ` [PATCH v8 3/6] iommu/tegra-smmu: Rename struct tegra_smmu_swgroup *group to *swgrp Nicolin Chen
2021-12-09  7:38   ` Nicolin Chen via iommu
2021-12-09  7:38 ` [PATCH v8 4/6] iommu/tegra-smmu: Use swgrp pointer instead of swgroup id Nicolin Chen
2021-12-09  7:38   ` Nicolin Chen via iommu
2021-12-09  7:38 ` [PATCH v8 5/6] iommu/tegra-smmu: Attach as pointer to tegra_smmu_group Nicolin Chen
2021-12-09  7:38   ` Nicolin Chen via iommu
2021-12-09  7:38 ` [PATCH v8 6/6] iommu/tegra-smmu: Add pagetable mappings to debugfs Nicolin Chen
2021-12-09  7:38   ` Nicolin Chen via iommu
2021-12-09 14:47   ` Dmitry Osipenko
2021-12-09 14:47     ` Dmitry Osipenko
2021-12-09 19:32     ` Nicolin Chen
2021-12-09 19:32       ` Nicolin Chen via iommu
2021-12-09 19:40       ` Dmitry Osipenko
2021-12-09 19:40         ` Dmitry Osipenko
2021-12-09 19:51         ` Nicolin Chen [this message]
2021-12-09 19:51           ` Nicolin Chen via iommu
2021-12-09 19:58           ` Dmitry Osipenko
2021-12-09 19:58             ` Dmitry Osipenko
2021-12-09 20:06             ` Nicolin Chen
2021-12-09 20:06               ` Nicolin Chen via iommu
2021-12-09 14:49   ` Dmitry Osipenko
2021-12-09 14:49     ` Dmitry Osipenko
2021-12-09 19:24     ` Nicolin Chen
2021-12-09 19:24       ` Nicolin Chen via iommu
2021-12-09 19:44       ` Dmitry Osipenko
2021-12-09 19:44         ` Dmitry Osipenko
2021-12-09 19:54         ` Nicolin Chen
2021-12-09 19:54           ` Nicolin Chen via iommu
2021-12-09 19:58           ` Dmitry Osipenko
2021-12-09 19:58             ` Dmitry Osipenko
2021-12-09 20:01             ` Nicolin Chen
2021-12-09 20:01               ` Nicolin Chen via iommu
2021-12-09 20:03               ` Dmitry Osipenko
2021-12-09 20:03                 ` Dmitry Osipenko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20211209195128.GA35526@Asurada-Nvidia \
    --to=nicolinc@nvidia.com \
    --cc=digetx@gmail.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jonathanh@nvidia.com \
    --cc=joro@8bytes.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=thierry.reding@gmail.com \
    --cc=vdumpa@nvidia.com \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.