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[76.242.90.12]) by smtp.gmail.com with ESMTPSA id h3-20020a05622a170300b002e008a93f8fsm469815qtk.91.2022.02.27.01.34.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 27 Feb 2022 01:34:48 -0800 (PST) From: jhubbard.send.patches@gmail.com X-Google-Original-From: jhubbard@nvidia.com To: Jens Axboe , Jan Kara , Christoph Hellwig , Dave Chinner , "Darrick J . Wong" , Theodore Ts'o , Alexander Viro , Miklos Szeredi , Andrew Morton , Chaitanya Kulkarni Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, LKML , John Hubbard Subject: [PATCH 3/6] block, fs: assert that key paths use iovecs, and nothing else Date: Sun, 27 Feb 2022 01:34:31 -0800 Message-Id: <20220227093434.2889464-4-jhubbard@nvidia.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220227093434.2889464-1-jhubbard@nvidia.com> References: <20220227093434.2889464-1-jhubbard@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: John Hubbard Upcoming changes to Direct IO will change it from acquiring pages via get_user_pages_fast(), to calling pin_user_pages_fast() instead. Place a few assertions at key points, that the pages are IOVEC (user pages), to enforce the assumptions that there are no kernel or pipe or other odd variations being passed. Signed-off-by: John Hubbard --- block/bio.c | 4 ++++ fs/direct-io.c | 2 ++ 2 files changed, 6 insertions(+) diff --git a/block/bio.c b/block/bio.c index b15f5466ce08..4679d6539e2d 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1167,6 +1167,8 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2); pages += entries_left * (PAGE_PTRS_PER_BVEC - 1); + WARN_ON_ONCE(!iter_is_iovec(iter)); + size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset); if (unlikely(size <= 0)) return size ? size : -EFAULT; @@ -1217,6 +1219,8 @@ static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter) BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2); pages += entries_left * (PAGE_PTRS_PER_BVEC - 1); + WARN_ON_ONCE(!iter_is_iovec(iter)); + size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset); if (unlikely(size <= 0)) return size ? size : -EFAULT; diff --git a/fs/direct-io.c b/fs/direct-io.c index 38bca4980a1c..7dbbbfef300d 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -169,6 +169,8 @@ static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio) { ssize_t ret; + WARN_ON_ONCE(!iter_is_iovec(sdio->iter)); + ret = iov_iter_get_pages(sdio->iter, dio->pages, LONG_MAX, DIO_PAGES, &sdio->from);