From: Al Viro <viro@zeniv.linux.org.uk>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@infradead.org>,
Ilya Dryomov <idryomov@gmail.com>, Jens Axboe <axboe@kernel.dk>,
linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-block@vger.kernel.org, linux-mm@kvack.org,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 2/3] iov_iter: introduce iov_iter_pin_user_pages*() routines
Date: Sun, 30 Aug 2020 21:17:05 +0100 [thread overview]
Message-ID: <20200830201705.GV1236603@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200829080853.20337-3-jhubbard@nvidia.com>
On Sat, Aug 29, 2020 at 01:08:52AM -0700, John Hubbard wrote:
> The new routines are:
> iov_iter_pin_user_pages()
> iov_iter_pin_user_pages_alloc()
>
> and those correspond to these pre-existing routines:
> iov_iter_get_pages()
> iov_iter_get_pages_alloc()
>
> Also, pipe_get_pages() and related are changed so as to pass
> down a "use_pup" (use pin_user_page() instead of get_page()) bool
> argument.
>
> Unlike the iov_iter_get_pages*() routines, the
> iov_iter_pin_user_pages*() routines assert that only ITER_IOVEC or
> ITER_PIPE items are passed in. They then call pin_user_page*(), instead
> of get_user_pages_fast() or get_page().
>
> Why: In order to incrementally change Direct IO callers from calling
> get_user_pages_fast() and put_page(), over to calling
> pin_user_pages_fast() and unpin_user_page(), there need to be mid-level
> routines that specifically call one or the other systems, for both page
> acquisition and page release.
Hmm... Do you plan to kill iov_iter_get_pages* off, eventually getting
rid of that use_pup argument?
next prev parent reply other threads:[~2020-08-30 20:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-29 8:08 [PATCH v2 0/3] bio: Direct IO: convert to pin_user_pages_fast() John Hubbard
2020-08-29 8:08 ` [PATCH v2 1/3] mm/gup: introduce pin_user_page() John Hubbard
2020-08-29 14:54 ` Christoph Hellwig
2020-08-29 21:57 ` John Hubbard
2020-08-29 8:08 ` [PATCH v2 2/3] iov_iter: introduce iov_iter_pin_user_pages*() routines John Hubbard
2020-08-29 14:58 ` Christoph Hellwig
2020-08-29 21:58 ` John Hubbard
2020-08-30 20:17 ` Al Viro [this message]
2020-08-30 20:44 ` John Hubbard
2020-08-29 8:08 ` [PATCH v2 3/3] bio: convert get_user_pages_fast() --> pin_user_pages_fast() John Hubbard
2020-08-29 15:02 ` Christoph Hellwig
2020-08-29 22:08 ` John Hubbard
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