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Date:   Thu, 6 Oct 2022 16:04:08 +0300
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     Fuad Tabba <tabba@google.com>
Cc:     Chao Peng <chao.p.peng@linux.intel.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
        linux-doc@vger.kernel.org, qemu-devel@nongnu.org,
        Paolo Bonzini <pbonzini@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
        Hugh Dickins <hughd@google.com>,
        Jeff Layton <jlayton@kernel.org>,
        "J . Bruce Fields" <bfields@fieldses.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Shuah Khan <shuah@kernel.org>, Mike Rapoport <rppt@kernel.org>,
        Steven Price <steven.price@arm.com>,
        "Maciej S . Szmigiero" <mail@maciej.szmigiero.name>,
        Vlastimil Babka <vbabka@suse.cz>,
        Vishal Annapurve <vannapurve@google.com>,
        Yu Zhang <yu.c.zhang@linux.intel.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com,
        ak@linux.intel.com, david@redhat.com, aarcange@redhat.com,
        ddutile@redhat.com, dhildenb@redhat.com,
        Quentin Perret <qperret@google.com>,
        Michael Roth <michael.roth@amd.com>, mhocko@suse.com,
        Muchun Song <songmuchun@bytedance.com>, wei.w.wang@intel.com
Subject: Re: [PATCH v8 1/8] mm/memfd: Introduce userspace inaccessible memfd
Message-ID: <20221006130408.2bnuikg6peilaycp@box.shutemov.name>
References: <20220915142913.2213336-1-chao.p.peng@linux.intel.com>
 <20220915142913.2213336-2-chao.p.peng@linux.intel.com>
 <CA+EHjTz=o9M47frGCXgNJ8J5_Rn=YjzZR5uvCTxStw+GfGE5kg@mail.gmail.com>
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On Thu, Oct 06, 2022 at 09:50:28AM +0100, Fuad Tabba wrote:
> Hi,
> 
> <...>
> 
> 
> > diff --git a/mm/memfd_inaccessible.c b/mm/memfd_inaccessible.c
> > new file mode 100644
> > index 000000000000..2d33cbdd9282
> > --- /dev/null
> > +++ b/mm/memfd_inaccessible.c
> 
> <...>
> 
> > +struct file *memfd_mkinaccessible(struct file *memfd)
> > +{
> > +       struct inaccessible_data *data;
> > +       struct address_space *mapping;
> > +       struct inode *inode;
> > +       struct file *file;
> > +
> > +       data = kzalloc(sizeof(*data), GFP_KERNEL);
> > +       if (!data)
> > +               return ERR_PTR(-ENOMEM);
> > +
> > +       data->memfd = memfd;
> > +       mutex_init(&data->lock);
> > +       INIT_LIST_HEAD(&data->notifiers);
> > +
> > +       inode = alloc_anon_inode(inaccessible_mnt->mnt_sb);
> > +       if (IS_ERR(inode)) {
> > +               kfree(data);
> > +               return ERR_CAST(inode);
> > +       }
> > +
> > +       inode->i_mode |= S_IFREG;
> > +       inode->i_op = &inaccessible_iops;
> > +       inode->i_mapping->private_data = data;
> > +
> > +       file = alloc_file_pseudo(inode, inaccessible_mnt,
> > +                                "[memfd:inaccessible]", O_RDWR,
> > +                                &inaccessible_fops);
> > +       if (IS_ERR(file)) {
> > +               iput(inode);
> > +               kfree(data);
> 
> I think this might be missing a return at this point.

Good catch! Thanks!

-- 
  Kiryl Shutsemau / Kirill A. Shutemov