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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <20230123173007.325544-1-dhowells@redhat.com> <20230123173007.325544-4-dhowells@redhat.com> To: David Hildenbrand Cc: dhowells@redhat.com, Al Viro , Christoph Hellwig , Matthew Wilcox , Jens Axboe , Jan Kara , Jeff Layton , Logan Gunthorpe , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , linux-mm@kvack.org Subject: Re: [PATCH v8 03/10] mm: Provide a helper to drop a pin/ref on a page MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <874545.1674571293.1@warthog.procyon.org.uk> Content-Transfer-Encoding: quoted-printable Date: Tue, 24 Jan 2023 14:41:33 +0000 Message-ID: <874546.1674571293@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: D06691A0015 X-Stat-Signature: 79omkhf9tfzscoxy74z55dnam6c7pyza X-HE-Tag: 1674571300-932453 X-HE-Meta: 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 jLsZh9zC dJ6S3KSXfWykZ2352ugM8EA3LeNycA+W0MqygQ1h5fjJVSb5C+abEmEEtbHaepRMStzItVF2PLED9V4Cqv1yFcpCIpzfUzCrEi1+Zlp5e+HaeeANbWY+r+zlXQnjIUSz8p46WP8V+BPxSgjKoRzpDd0ruX+jmxzeSTJjYqO/edFbyBJspK7Wu0v1Bbm5Y7sb6PxXU7QUbX9jmG5o8RWih1rUnvrTPIpqSqOltjdwTqmjm/giaVDGygU1vn5XiRUKQHgQOatd4mOA62vR+nrubTc9TFMHj8N04DlHFtGATVFiUbBaXelcaGwk6XmcrG92vaLy5AzC9w2BCHM+Bi5BIeCdmvnL8t3fiYgJAQaT9T+4vTfxn5cr5kvlsMpjQGM7fNDVT X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: David Hildenbrand wrote: > > Provide a helper in the get_user_pages code to drop a pin or a ref on = a > > page based on being given FOLL_GET or FOLL_PIN in its flags argument o= r do > > nothing if neither is set. > = > Does the FOLL_GET part still apply to this patch set? Yes. Christoph insisted that the bio conversion patch be split up. That means there's an interval where you can get FOLL_GET from that. However, since Jason wants to hide FOLL_PUT, this is going to have to be removed an= d the switching done in the bio code for the bio case (until that reduces to just pinning) and the skbuff cleanup code (when that is eventually done - = that will have the possibility of skbuffs comprising a mix of ref'd, pinned and unpinned data, albeit in separate fragments; I've posted patches that illustrate this[1]). David https://lore.kernel.org/all/167391047703.2311931.8115712773222260073.stgit= @warthog.procyon.org.uk/ [1] Patches 33-34