From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE9934D2EDE; Tue, 9 Jun 2026 19:15:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781032511; cv=none; b=QEJjpK0PyvOsQKVWHfafG9hz2ItOQomGoa/g0Ok72MRsfA1QJvJdhjXHvy8EXYMZwEK+UX4SbOZGooGTQEACXlMP/BD7RPeS3cX1TcL8l5yxAxo8TJzSUL9eNFl+3ajjoJnV/VIO+CaBssGMCVKk1r21g6a6pYUJ2Z9RlgaWXew= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781032511; c=relaxed/simple; bh=5+GUPrHafhi7e06njalxCX3qEtJzRjQWZ+jqQPaKrWg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=hjav/kASQxaweoDcANSNnt5QmSOarzkFGiOHHqzponrBSaV/J9LO1W1cb/YF4XI5lavm8EH0fTC/2awxY6bdr10NnMr4gqPlnmqDwxdSkxcEO71E9TqlJ6rLSH88BnYasq216NyXwN84n/b/Bk1MIpXuCBKBOw1l82BUXJQ4cPk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ILJ4ZGV3; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ILJ4ZGV3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4970E1F00898; Tue, 9 Jun 2026 19:15:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781032510; bh=64hvSmLNolq6thR/XE1WahjnyPiD4J8xEpWXph8IhxU=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=ILJ4ZGV3IqhZKH9TQnw/S+0cy9b56XT90Qwagujd3q8x0Dr0hMVaLhsl/3XdWRHVq E6koHy5xCOlv8iDzC1IwtRwNRrWU412XAyZNC8ne/hwGDhILazbZ8i3t09gJpDalis wJ0JqcmxEp07yCSIsELbbLuyWnexgc30pw09eSenYfYBeYqqBKkesHqwHL/6pKdmsb 4Sbo+qipLgem/kIYtOsmUWP+yPGyjBPF5WBQ5LvaCYixLpsvj0//8c6ssvZYqUxK/J s47/hjd4zM0UDTuo3X9bC5ZK1Bv+5XlqZ0pa4vGdSaN99upOFsPJQfyX19HJGdE77r hnZc2RwqC5h6w== From: Andreas Hindborg Date: Tue, 09 Jun 2026 21:08:42 +0200 Subject: [PATCH v2 63/83] block: rust: add `Segment::copy_to_page_limit` Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260609-rnull-v6-19-rc5-send-v2-63-82c7404542e2@kernel.org> References: <20260609-rnull-v6-19-rc5-send-v2-0-82c7404542e2@kernel.org> In-Reply-To: <20260609-rnull-v6-19-rc5-send-v2-0-82c7404542e2@kernel.org> To: "Liam R. Howlett" , Alice Ryhl , Anna-Maria Behnsen , Benno Lossin , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Boqun Feng , Danilo Krummrich , FUJITA Tomonori , Frederic Weisbecker , Gary Guo , Jens Axboe , John Stultz , Lorenzo Stoakes , Lyude Paul , Miguel Ojeda , Stephen Boyd , Thomas Gleixner , Trevor Gross , "Liam R. Howlett" , Boqun Feng , Lorenzo Stoakes Cc: Andreas Hindborg , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, rust-for-linux@vger.kernel.org X-Mailer: b4 0.16-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=2086; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=5+GUPrHafhi7e06njalxCX3qEtJzRjQWZ+jqQPaKrWg=; b=kA0DAAoB+lApCKrFvdAByyZiAGooZO2hozbAw63hLJZ4uFn9jmNCLHArRdSgJaa5AlVUL8B6Q 4kCMwQAAQoAHRYhBFeK2cjZZnYmKsBqhvpQKQiqxb3QBQJqKGTtAAoJEPpQKQiqxb3Qx+cP/2/W ms5Tmyn1Z/jTN07+FyjyTUSksEZV2eNtSnPfn+USQ3MWIf63EoTMejbL93puBw4G9QuRs9mezAZ jdtRrCILq3VtPqdFtdYRIrjZzeSHKZy9u2l+9QmI8uAIkMl6TwHxswM1XjGYB09WNl3jvTpysFa QLVzHdICSrtPOK1TvUCJUs3zA92cxKEY84XPRVpGh1jnWleCYI7ZEtiuzlLseEIFgGhv3oSguWL xdEKUluwi/j+kLqo1LMR856+wcpzl8ujsESFklsm5nBW6Wd1AygX8RFUTzD+DuemwWhAhiCzeO+ JEdcwfO3MNzTi3roXxSHuglsRaol4BJO5dV+JXx/q37ns0vuxc5dBdJ+4xh1w4IL3az5kB6Gdsi DABd7XeiTBCf3ZUicvObJ+p/w1jBtoZ5TE2SU5UH7c/DDnoBlF5/WIXJwkKWUvq0Mj1xQ1U1EF8 mfH26FpRa5F4Ol3QOooJVp5hJqtthHVXlyjJqdOuWi+A/PDtqQ1LUNuEALgRDO/ec+C13MDo1ZN MpzCaFWHq3AA0UEJ4qtTLO8TToZ6QmTvhMgYFDelcOErKCXqcpFViSa3qcKH9aMY61sNysMxuUE Ay2NQVXelzeffKyV8c8Lg2+DWJhhwbCwUT/XKAJ/4at764te4+OUcIfOUzMrcxMjfiNzpP9Urm6 +DfSb X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 Add a method to `block::mq::bio::Segment` to copy a bounded amount of bytes to a page. Signed-off-by: Andreas Hindborg --- rust/kernel/block/bio/vec.rs | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) diff --git a/rust/kernel/block/bio/vec.rs b/rust/kernel/block/bio/vec.rs index 61d83a07397f..82e89a1d17c3 100644 --- a/rust/kernel/block/bio/vec.rs +++ b/rust/kernel/block/bio/vec.rs @@ -102,13 +102,38 @@ pub fn truncate(&mut self, new_len: u32) { /// Returns the number of bytes copied. #[inline(always)] pub fn copy_to_page(&mut self, dst_page: Pin<&mut SafePage>, dst_offset: usize) -> usize { + self.copy_to_page_limit(dst_page, dst_offset, 0) + } + + /// Copy data of this segment into `dst_page`. + /// + /// Copies at most `limit` bytes of data from the current offset to the next page boundary. That + /// is `PAGE_SIZE - (self.offeset() % PAGE_SIZE)` bytes of data. Data is placed at offset + /// `self.offset()` in the target page. This call will advance offset and reduce length of + /// `self`. + /// + /// If `limit` is zero it is ignored. + /// + /// Returns the number of bytes copied. + #[inline(always)] + pub fn copy_to_page_limit( + &mut self, + dst_page: Pin<&mut SafePage>, + dst_offset: usize, + limit: usize, + ) -> usize { // SAFETY: We are not moving out of `dst_page`. let dst_page = unsafe { Pin::into_inner_unchecked(dst_page) }; let src_offset = self.offset() % PAGE_SIZE; debug_assert!(dst_offset <= PAGE_SIZE); - let length = (PAGE_SIZE - src_offset) + let mut length = (PAGE_SIZE - src_offset) .min(self.len() as usize) .min(PAGE_SIZE - dst_offset); + + if limit > 0 { + length = length.min(limit); + } + let page_idx = self.offset() / PAGE_SIZE; // SAFETY: self.bio_vec is valid and thus bv_page must be a valid -- 2.51.2