From: Al Viro <viro@zeniv.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>,
cluster-devel <cluster-devel@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jan Kara <jack@suse.cz>, Matthew Wilcox <willy@infradead.org>
Subject: Re: [RFC 5/9] iov_iter: Add iov_iter_fault_in_writeable()
Date: Sat, 12 Jun 2021 23:38:16 +0000 [thread overview]
Message-ID: <YMVFaPZtg7ijvYe2@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <CAHk-=wgoBx_GzTQMj_HQGAR+f+7VRJ6JbU9UBfuPHKLfTVMPGQ@mail.gmail.com>
On Sat, Jun 12, 2021 at 04:17:30PM -0700, Linus Torvalds wrote:
> On Sat, Jun 12, 2021 at 2:47 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > O_DIRECT case is a PITA - there we use GUP and there's no way
> > to tell GUP that in the current situation we do *NOT* want to hit
> > ->fault()/->page_mkwrite()/etc. pagefault_disable() won't be even
> > noticed there...
>
> Well, we could change that.
>
> And we do have get_user_pages_fast_only() these days.
FWIW, I'm looking through the users of iov_iter_get_pages{,_alloc}()
right now; their semantics feels somewhat wrong. Will follow up
when I finish looking through that pile...
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@zeniv.linux.org.uk>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [RFC 5/9] iov_iter: Add iov_iter_fault_in_writeable()
Date: Sat, 12 Jun 2021 23:38:16 +0000 [thread overview]
Message-ID: <YMVFaPZtg7ijvYe2@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <CAHk-=wgoBx_GzTQMj_HQGAR+f+7VRJ6JbU9UBfuPHKLfTVMPGQ@mail.gmail.com>
On Sat, Jun 12, 2021 at 04:17:30PM -0700, Linus Torvalds wrote:
> On Sat, Jun 12, 2021 at 2:47 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > O_DIRECT case is a PITA - there we use GUP and there's no way
> > to tell GUP that in the current situation we do *NOT* want to hit
> > ->fault()/->page_mkwrite()/etc. pagefault_disable() won't be even
> > noticed there...
>
> Well, we could change that.
>
> And we do have get_user_pages_fast_only() these days.
FWIW, I'm looking through the users of iov_iter_get_pages{,_alloc}()
right now; their semantics feels somewhat wrong. Will follow up
when I finish looking through that pile...
next prev parent reply other threads:[~2021-06-12 23:39 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 17:01 [RFC 0/9] gfs2: handle page faults during read and write Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 1/9] gfs2: Clean up the error handling in gfs2_page_mkwrite Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 2/9] gfs2: Add wrapper for iomap_file_buffered_write Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 3/9] gfs2: Add gfs2_holder_is_compatible helper Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 4/9] gfs2: Fix mmap + page fault deadlocks (part 1) Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-06-01 6:00 ` Linus Torvalds
2021-06-01 6:00 ` [Cluster-devel] " Linus Torvalds
2021-06-02 11:16 ` Andreas Gruenbacher
2021-06-02 11:16 ` [Cluster-devel] " Andreas Gruenbacher
2021-06-11 16:25 ` Al Viro
2021-06-11 16:25 ` [Cluster-devel] " Al Viro
2021-06-12 21:05 ` Al Viro
2021-06-12 21:05 ` [Cluster-devel] " Al Viro
2021-06-12 21:35 ` Al Viro
2021-06-12 21:35 ` [Cluster-devel] " Al Viro
2021-06-13 8:44 ` Steven Whitehouse
2021-06-13 8:44 ` Steven Whitehouse
2021-05-31 17:01 ` [RFC 5/9] iov_iter: Add iov_iter_fault_in_writeable() Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:12 ` Al Viro
2021-05-31 17:12 ` [Cluster-devel] " Al Viro
2021-06-12 21:12 ` Al Viro
2021-06-12 21:12 ` [Cluster-devel] " Al Viro
2021-06-12 21:33 ` Linus Torvalds
2021-06-12 21:33 ` [Cluster-devel] " Linus Torvalds
2021-06-12 21:47 ` Al Viro
2021-06-12 21:47 ` [Cluster-devel] " Al Viro
2021-06-12 23:17 ` Linus Torvalds
2021-06-12 23:17 ` [Cluster-devel] " Linus Torvalds
2021-06-12 23:38 ` Al Viro [this message]
2021-06-12 23:38 ` Al Viro
2021-05-31 17:01 ` [RFC 6/9] gfs2: Add wrappers for accessing journal_info Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 7/9] gfs2: Encode glock holding and retry flags in journal_info Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 8/9] gfs2: Add LM_FLAG_OUTER glock holder flag Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-05-31 17:01 ` [RFC 9/9] gfs2: Fix mmap + page fault deadlocks (part 2) Andreas Gruenbacher
2021-05-31 17:01 ` [Cluster-devel] " Andreas Gruenbacher
2021-06-01 5:47 ` Linus Torvalds
2021-06-01 5:47 ` [Cluster-devel] " Linus Torvalds
2021-05-31 17:57 ` [Cluster-devel] [RFC 0/9] gfs2: handle page faults during read and write Linus Torvalds
2021-05-31 20:35 ` Andreas Gruenbacher
2021-05-31 20:35 ` [Cluster-devel] " Andreas Gruenbacher
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