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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3997f9a50c1sm3609957f8f.38.2025.03.21.15.46.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Mar 2025 15:46:11 -0700 (PDT) From: David Laight To: linux-kernel@vger.kernel.org Cc: David Laight , Linus Torvalds , Jens Axboe , David Howells , Matthew Wilcox , Andrew Morton , Alexander Viro Subject: [PATCH next 0/3] iov: Optimise user copies Date: Fri, 21 Mar 2025 22:45:54 +0000 Message-Id: <20250321224557.3847-1-david.laight.linux@gmail.com> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The speculation barrier in access_ok() is expensive. The first patch removes the initial checks when reading the iovec[]. The checks are repeated before the actual copy. The second patch uses 'user address masking' if supported. The third removes a lot of code for single entry iovec[]. David Laight (3): Remove access_ok() from import_iovec() Use masked user accesses Optimise __import_iovec_ubuf() lib/iov_iter.c | 97 ++++++++++++++++++++++++++++++++------------------ 1 file changed, 63 insertions(+), 34 deletions(-) -- 2.39.5