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[216.228.112.21]) by smtp.gmail.com with ESMTPSA id a15sm34153364pgw.3.2019.07.23.21.25.22 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 23 Jul 2019 21:25:23 -0700 (PDT) From: john.hubbard@gmail.com X-Google-Original-From: jhubbard@nvidia.com To: Andrew Morton Cc: Alexander Viro , Anna Schumaker , "David S . Miller" , Dominique Martinet , Eric Van Hensbergen , Jason Gunthorpe , Jason Wang , Jens Axboe , Latchesar Ionkov , "Michael S . Tsirkin" , Miklos Szeredi , Trond Myklebust , Christoph Hellwig , Matthew Wilcox , linux-mm@kvack.org, LKML , ceph-devel@vger.kernel.org, kvm@vger.kernel.org, linux-block@vger.kernel.org, linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, samba-technical@lists.samba.org, v9fs-developer@lists.sourceforge.net, virtualization@lists.linux-foundation.org, =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , John Hubbard , Jan Kara , Dan Williams , Johannes Thumshirn , Ming Lei , Dave Chinner Subject: [PATCH 02/12] iov_iter: add helper to test if an iter would use GUP v2 Date: Tue, 23 Jul 2019 21:25:08 -0700 Message-Id: <20190724042518.14363-3-jhubbard@nvidia.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190724042518.14363-1-jhubbard@nvidia.com> References: <20190724042518.14363-1-jhubbard@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-NVConfidentiality: public Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jérôme Glisse Add a helper to test if call to iov_iter_get_pages*() with a given iter would result in calls to GUP (get_user_pages*()). We want to use different tracking of page references if they are coming from GUP (get_user_pages*()) and thus we need to know when GUP is used for a given iter. Changes since Jérôme's original patch: * iov_iter_get_pages_use_gup(): do not return true for the ITER_PIPE case, because iov_iter_get_pages() calls pipe_get_pages(), which in turn uses get_page(), not get_user_pages(). * Remove some obsolete code, as part of rebasing onto Linux 5.3. * Fix up the kerneldoc comment to "Return:" rather than "Returns:", and a few other grammatical tweaks. Signed-off-by: Jérôme Glisse Signed-off-by: John Hubbard Cc: linux-fsdevel@vger.kernel.org Cc: linux-block@vger.kernel.org Cc: linux-mm@kvack.org Cc: John Hubbard Cc: Jan Kara Cc: Dan Williams Cc: Alexander Viro Cc: Johannes Thumshirn Cc: Christoph Hellwig Cc: Jens Axboe Cc: Ming Lei Cc: Dave Chinner Cc: Jason Gunthorpe Cc: Matthew Wilcox --- include/linux/uio.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/include/linux/uio.h b/include/linux/uio.h index ab5f523bc0df..2a179af8e5a7 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -86,6 +86,17 @@ static inline unsigned char iov_iter_rw(const struct iov_iter *i) return i->type & (READ | WRITE); } +/** + * iov_iter_get_pages_use_gup - report if iov_iter_get_pages(i) uses GUP + * @i: iterator + * Return: true if a call to iov_iter_get_pages*() with the iter provided in + * the argument would result in the use of get_user_pages*() + */ +static inline bool iov_iter_get_pages_use_gup(const struct iov_iter *i) +{ + return iov_iter_type(i) == ITER_IOVEC; +} + /* * Total number of bytes covered by an iovec. * -- 2.22.0