From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8D41A32FA1B for ; Thu, 18 Dec 2025 08:34:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766046884; cv=none; b=l+sd2lZqdbFgL8tUEs5xyifG0fvBV4DpPP+pZxgZZxZtueUY7XfmghY2cwTKG1ToTcSmHpxrsLuJ7/aw3oJZb+vVCu5MMgdM+XtFHtQJLfnR1btXjZS3yDx642v46pO9xnYUkY9A2nJQ/PxQONQFjmo0bbjjizAyxjhGhtenqnA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766046884; c=relaxed/simple; bh=j4pCXsrkwTGJ0Yt8ShUCMPcAaExRESShE0RxC+SZfjc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gQFD+YBOynBdajY7+c8nTBxNR8yn1YKLcM+/82HI/jIvIS5WCLGMzrYvDs6RrZOmjD94eUrtgvct3fSLJ1a8ZuUrzLOOGRJkDSFT1U2mcvY8yEcbQyKdR9hmpLNKOOP3cNThEEnN4+9lyq7SQdn7J4j0DkI1GgC/Td81zYydPEY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=XEXEO/2A; arc=none smtp.client-ip=209.85.210.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XEXEO/2A" Received: by mail-pf1-f180.google.com with SMTP id d2e1a72fcca58-7aa2170adf9so358473b3a.0 for ; Thu, 18 Dec 2025 00:34:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1766046882; x=1766651682; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=XiB+Fy0CW+7OP9Cqy2W6zdEPfAr8bWS3LGB82D8pXcM=; b=XEXEO/2AO3w87ZDj2pveF9XPvlJOxbfEm2lEiQo/z7z+O+b05qQ5WGSuuEPZeeSnim PBCffGF2n05mdcAKSd1t3PsLslrlqd36Qg+cnsBZ4Ub/uUbOXwiutMWSIA6FSCOdlJe6 ixXRP2hXyqcmPCL0bHkzs0bFpso9pxxnVW7p87gZHFCU48OzB2l3dnrZoSYuidmUZDAi PfZdPDz5Ntw+DJkcTycCn4R+aVHvQC9LLUwmJppdWg4Zkng2L7NDygN5Qd2LU0ZAt68V mqDO0Yj45JlsO/51qsBtXzVlwoBxMmu2XLxk8AyZsvG9SrYtfi+X9HVUBX/yTobdG1CK q1Mg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1766046882; x=1766651682; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=XiB+Fy0CW+7OP9Cqy2W6zdEPfAr8bWS3LGB82D8pXcM=; b=SErMam0yjq6K5aaLSSw7YjX7eVwXfZOCTIX+UOfXd1asUHktkwIFCAjyFu9Onj/8wr TDKdRgfWBufoPeGGrOJekpjKvarE9Qv6LEPgRKgt+tVrL52/KxsvVrrlpMhr4kHOat35 flv11jcdZQZxWlfCCL44mzQvLWZHxOXtHAzfLtjK3UIBJ8i++wC/z/dAtnGjpOvhRpLH DYFcRZV2iez7wQhcLJ1ksqpn6o3qidCMGz8hrFBgv7sfS5E/xGHal34y6Ehb7wDR1fnb 79lXIhmXgoLrdCKgXY33NOu1lXxXEvCS9UH+7nCvq+SKOWvyn0KaR4rDNmPpS0hKE/hW wCPQ== X-Forwarded-Encrypted: i=1; AJvYcCWeXm7+eFXakLUv8y2oPkhZpgaPlk5QqP2DmXxbrbo5e6xrC739HBRtyfmDcRK/IEnact29VWcUJg==@vger.kernel.org X-Gm-Message-State: AOJu0Yz3bUjIsQTYi3sB/JKZeyLaOMzhcfq+c3KIhRxcQ2ntNxMKRfM0 BFwEY1ZVjFLXe5WLQuyU5LyAJ2lDUDJTqrefgfJNRU6PWez1T+KT18aE X-Gm-Gg: AY/fxX44vgPpCAwGUOhN/i9HImFdbll42RCB6HFuBhaWOt3QzBiixzOm/1DNI4AKDFX WZ51nBV22IIrUJLJvpKG2lYU4PEj1zk8AI8XaSnpVS/lIzqSlTsBeGr6ZYMg15YSo9u7wbkGrnG XC57WGKjdO5Yhcpq+4lEiLW0DqfyEFqt1JI0Glf1oULW/BeS3JLv6hszIHAVopJe7fSbvMqiZyt z+0PHVfuUEY07VVXK5IXmmKhVTaVjkHPlr1Vpi8DgFssjJhdNnR0FWqg99ujtsqGEcHnfh5/74T xFg+0Zu9ZGj9PadmKEzCdJZAqJndwGs+qdye+3sngJUSkQS+IDd0ypqXF/HJDNIv3Gi1iF5qOQ0 n10GrxhpobjNn2VZcA/UkeLx22YMNeBz0FtIwWXHasX5C24t3v9V9VqtdhlhOg6yKI66gYhCULf PtFIPZFGdNq2NEJQ== X-Google-Smtp-Source: AGHT+IGwUHxIZlG18VV1M2bBcER/DVkm4R1Wng+/OHLLt7cl6x6eUBvkwRac2QPIiryNLUgHaAsj0A== X-Received: by 2002:a05:6a20:7285:b0:35d:6b4e:91f1 with SMTP id adf61e73a8af0-369ae0ac5a8mr19292293637.34.1766046881763; Thu, 18 Dec 2025 00:34:41 -0800 (PST) Received: from localhost ([2a03:2880:ff::]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a2d1926d45sm17258245ad.78.2025.12.18.00.34.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Dec 2025 00:34:41 -0800 (PST) From: Joanne Koong To: miklos@szeredi.hu, axboe@kernel.dk Cc: bschubert@ddn.com, asml.silence@gmail.com, io-uring@vger.kernel.org, csander@purestorage.com, xiaobing.li@samsung.com, linux-fsdevel@vger.kernel.org Subject: [PATCH v2 05/25] io_uring/kbuf: support kernel-managed buffer rings in buffer selection Date: Thu, 18 Dec 2025 00:32:59 -0800 Message-ID: <20251218083319.3485503-6-joannelkoong@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251218083319.3485503-1-joannelkoong@gmail.com> References: <20251218083319.3485503-1-joannelkoong@gmail.com> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Allow kernel-managed buffers to be selected. This requires modifying the io_br_sel struct to separate the fields for address and val, since a kernel address cannot be distinguished from a negative val when error checking. Auto-commit any selected kernel-managed buffer. Signed-off-by: Joanne Koong --- include/linux/io_uring_types.h | 8 ++++---- io_uring/kbuf.c | 15 ++++++++++++--- 2 files changed, 16 insertions(+), 7 deletions(-) diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index e1adb0d20a0a..36fac08db636 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -93,13 +93,13 @@ struct io_mapped_region { */ struct io_br_sel { struct io_buffer_list *buf_list; - /* - * Some selection parts return the user address, others return an error. - */ union { + /* for classic/ring provided buffers */ void __user *addr; - ssize_t val; + /* for kernel-managed buffers */ + void *kaddr; }; + ssize_t val; }; diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index 65102aaadd15..c98cecb56b8c 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -155,7 +155,8 @@ static int io_provided_buffers_select(struct io_kiocb *req, size_t *len, return 1; } -static bool io_should_commit(struct io_kiocb *req, unsigned int issue_flags) +static bool io_should_commit(struct io_kiocb *req, struct io_buffer_list *bl, + unsigned int issue_flags) { /* * If we came in unlocked, we have no choice but to consume the @@ -170,7 +171,11 @@ static bool io_should_commit(struct io_kiocb *req, unsigned int issue_flags) if (issue_flags & IO_URING_F_UNLOCKED) return true; - /* uring_cmd commits kbuf upfront, no need to auto-commit */ + /* kernel-managed buffers are auto-committed */ + if (bl->flags & IOBL_KERNEL_MANAGED) + return true; + + /* multishot uring_cmd commits kbuf upfront, no need to auto-commit */ if (!io_file_can_poll(req) && req->opcode != IORING_OP_URING_CMD) return true; return false; @@ -201,8 +206,12 @@ static struct io_br_sel io_ring_buffer_select(struct io_kiocb *req, size_t *len, req->buf_index = READ_ONCE(buf->bid); sel.buf_list = bl; sel.addr = u64_to_user_ptr(READ_ONCE(buf->addr)); + if (bl->flags & IOBL_KERNEL_MANAGED) + sel.kaddr = (void *)buf->addr; + else + sel.addr = u64_to_user_ptr(READ_ONCE(buf->addr)); - if (io_should_commit(req, issue_flags)) { + if (io_should_commit(req, bl, issue_flags)) { io_kbuf_commit(req, sel.buf_list, *len, 1); sel.buf_list = NULL; } -- 2.47.3