From: Christoph Hellwig <hch@infradead.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@infradead.org>,
John Hubbard <jhubbard@nvidia.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>, Miklos Szeredi <miklos@szeredi.hu>,
"Darrick J . Wong" <djwong@kernel.org>,
Trond Myklebust <trond.myklebust@hammerspace.com>,
Anna Schumaker <anna@kernel.org>,
David Hildenbrand <david@redhat.com>,
Logan Gunthorpe <logang@deltatee.com>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-xfs@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 4/7] iov_iter: new iov_iter_pin_pages*() routines
Date: Thu, 22 Sep 2022 07:38:25 -0700 [thread overview]
Message-ID: <YyxzYTlyGhbb2MOu@infradead.org> (raw)
In-Reply-To: <YyvG+Oih2A37Grcf@ZenIV>
On Thu, Sep 22, 2022 at 03:22:48AM +0100, Al Viro wrote:
> What I'd like to have is the understanding of the places where we drop
> the references acquired by iov_iter_get_pages(). How do we decide
> whether to unpin?
Add a iov_iter_unpin_pages that does the right thing based on the
type. (block will need a modified copy of it as it doesn't keep
the pages array around, but logic will be the same).
> E.g. pipe_buffer carries a reference to page and no
> way to tell whether it's a pinned one; results of iov_iter_get_pages()
> on ITER_IOVEC *can* end up there, but thankfully only from data-source
> (== WRITE, aka. ITER_SOURCE) iov_iter. So for those we don't care.
> Then there's nfs_request; AFAICS, we do need to pin the references in
> those if they are coming from nfs_direct_read_schedule_iovec(), but
> not if they come from readpage_async_filler(). How do we deal with
> coalescence, etc.? It's been a long time since I really looked at
> that code... Christoph, could you give any comments on that one?
I think the above should work, but I'll need to look at the NFS code
in more detail to be sure.
next prev parent reply other threads:[~2022-09-22 14:39 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 4:18 [PATCH v2 0/7] convert most filesystems to pin_user_pages_fast() John Hubbard
2022-08-31 4:18 ` [PATCH v2 1/7] mm: change release_pages() to use unsigned long for npages John Hubbard
2022-08-31 4:18 ` [PATCH v2 2/7] mm/gup: introduce pin_user_page() John Hubbard
2022-09-06 6:37 ` Christoph Hellwig
2022-09-06 7:12 ` John Hubbard
2022-08-31 4:18 ` [PATCH v2 3/7] block: add dio_w_*() wrappers for pin, unpin user pages John Hubbard
2022-08-31 4:18 ` [PATCH v2 4/7] iov_iter: new iov_iter_pin_pages*() routines John Hubbard
2022-09-01 0:42 ` Al Viro
2022-09-01 1:48 ` John Hubbard
2022-09-06 6:47 ` Christoph Hellwig
2022-09-06 7:44 ` John Hubbard
2022-09-06 7:48 ` Christoph Hellwig
2022-09-06 7:58 ` John Hubbard
2022-09-07 8:50 ` Christoph Hellwig
2022-09-06 10:21 ` Jan Kara
2022-09-07 8:45 ` Christoph Hellwig
2022-09-14 3:51 ` Al Viro
2022-09-14 14:52 ` Jan Kara
2022-09-14 16:42 ` Al Viro
2022-09-15 8:16 ` Jan Kara
2022-09-16 1:55 ` Al Viro
2022-09-20 5:02 ` Al Viro
2022-09-22 14:36 ` Christoph Hellwig
2022-09-22 14:43 ` David Hildenbrand
2022-09-22 14:45 ` Christoph Hellwig
2022-09-22 2:22 ` Al Viro
2022-09-22 6:09 ` John Hubbard
2022-09-22 11:29 ` Jan Kara
2022-09-23 3:19 ` Al Viro
2022-09-23 4:05 ` John Hubbard
2022-09-23 8:39 ` Christoph Hellwig
2022-09-23 12:22 ` Jan Kara
2022-09-23 4:34 ` John Hubbard
2022-09-22 14:38 ` Christoph Hellwig [this message]
2022-09-23 4:22 ` Al Viro
2022-09-23 8:44 ` Christoph Hellwig
2022-09-23 16:13 ` Al Viro
2022-09-26 15:53 ` Christoph Hellwig
2022-09-26 19:55 ` Al Viro
2022-09-22 14:31 ` Christoph Hellwig
2022-09-22 14:36 ` Al Viro
2022-08-31 4:18 ` [PATCH v2 5/7] block, bio, fs: convert most filesystems to pin_user_pages_fast() John Hubbard
2022-09-06 6:48 ` Christoph Hellwig
2022-09-06 7:15 ` John Hubbard
2022-08-31 4:18 ` [PATCH v2 6/7] NFS: direct-io: convert to FOLL_PIN pages John Hubbard
2022-09-06 6:49 ` Christoph Hellwig
2022-09-06 7:16 ` John Hubbard
2022-08-31 4:18 ` [PATCH v2 7/7] fuse: convert direct IO paths to use FOLL_PIN John Hubbard
2022-08-31 10:37 ` Miklos Szeredi
2022-09-01 1:33 ` John Hubbard
2022-09-06 6:36 ` [PATCH v2 0/7] convert most filesystems to pin_user_pages_fast() Christoph Hellwig
2022-09-06 7:10 ` John Hubbard
2022-09-06 7:22 ` Christoph Hellwig
2022-09-06 7:37 ` John Hubbard
2022-09-06 7:46 ` Christoph Hellwig
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