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From: John Hubbard <jhubbard@nvidia.com>
To: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	Christoph Hellwig <hch@infradead.org>,
	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 21:34:26 -0700	[thread overview]
Message-ID: <c46b63f6-d222-36cb-ffb4-558df20edf24@nvidia.com> (raw)
In-Reply-To: <20220922112935.pep45vfqfw5766gq@quack3>

On 9/22/22 04:29, Jan Kara wrote:
> I don't think this will work. The pin nfs_direct_read_schedule_iovec()
> obtains needs to be released once the IO is completed. Not once the IO is
> submitted. Notice how nfs_create_request()->__nfs_create_request() gets
> another page reference which is released on completion
> (nfs_direct_read_completion->nfs_release_request->nfs_page_group_destroy->
> nfs_free_request->nfs_clear_request). And we need to stop releasing the
> obtained pin in nfs_direct_read_schedule_iovec() (and acquiring another
> reference in __nfs_create_request()) and instead propagate it to
> nfs_clear_request() where it can get released.
> 
> 								Honza

OK, now I see how that is supposed to work, thanks for explaining!


thanks,

-- 
John Hubbard
NVIDIA


  parent reply	other threads:[~2022-09-23  4:34 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 [this message]
2022-09-22 14:38                       ` Christoph Hellwig
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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