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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 22 Oct 2021 09:22:51 -1000
Message-ID: <CAHk-=wg4t2t1AaBDyMfOVhCCOiLLjCB5TFVgZcV4Pr8X2qptJw@mail.gmail.com>
Subject: Re: [PATCH v8 00/17] gfs2: Fix mmap + page fault deadlocks
To:     Catalin Marinas <catalin.marinas@arm.com>
Cc:     Andreas Gruenbacher <agruenba@redhat.com>,
        Paul Mackerras <paulus@ozlabs.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        "Darrick J. Wong" <djwong@kernel.org>, Jan Kara <jack@suse.cz>,
        Matthew Wilcox <willy@infradead.org>,
        cluster-devel <cluster-devel@redhat.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        ocfs2-devel@oss.oracle.com, kvm-ppc@vger.kernel.org,
        linux-btrfs <linux-btrfs@vger.kernel.org>
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On Fri, Oct 22, 2021 at 8:06 AM Catalin Marinas <catalin.marinas@arm.com> wrote:
>
> Probing only the first byte(s) in fault_in() would be ideal, no need to
> go through all filesystems and try to change the uaccess/probing order.

Let's try that. Or rather: probing just the first page - since there
are users like that btrfs ioctl, and the direct-io path.

                  Linus