From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) (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 3AB5E26F28F for ; Thu, 18 Dec 2025 08:34:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766046878; cv=none; b=in1r2ZYZL5CjcWPNkgBcj6HujnsGj0H9jtcI3Dc8fzptemICD1vVdP6lcq5hPS1YWrsE1+y+ovLLFjSyc/+w08WqPaz5shYHgUxBLyyTGD8rhkFfcuynSG56aiDaRxdXI554uL5woWLETWJJGVcwGU5Ithfd0zcbWxK2yaGwutw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766046878; c=relaxed/simple; bh=2bl1I2nGDFhxzgXjKcGi7d1dbtnWWYC+yqHyoAr/ZWQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=akgqrGuwvaGFv3cE1zqwFb+e4P2xY2HXEfVGVr8g55aB/xeGSQymopR0r06XobxSO9iDQvUFToDTyCEHq9iJAW0sUqkwl87VpEcDhskhFxFYvAUbf4fD1OlvNN690tXL6YIErPJTeXYm/P4ekCYvIyGCwUIRFbqSv6oxnj7Nl7Y= 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=GEJcM6ua; arc=none smtp.client-ip=209.85.214.171 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="GEJcM6ua" Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-2a0ac29fca1so3428685ad.2 for ; Thu, 18 Dec 2025 00:34:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1766046875; x=1766651675; 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=zGm2YYLVF+NHRLQ/f0+pGaC5F7muCq47qD8Hd3HU+QA=; b=GEJcM6ua7JcIZfyS+akR9z4NCe8NDwlxgfy3saKTTlB0z85tNZGoKquzUDIBK3CRii yJ01XSfXdY64Xqm/CEZ4ao3IlTgdZamqU8xGJrHfr6GfFzWbdX1TpxY8LbpJFR1crsKO di+P1xHECMfhaQ8X147zNDqG8EGXM151sTSEZWpf5B3pdLRkdl+yTVN4bHN6DEuwxdms bxPWhVBBGKeuslLnjalFOGM3f1t4NCk0tbKfRTXMbrOXA5M4mU+eW6pAPzajiYxcA/ub VqOrQtWMlgJC8kq3Atx73j/HzHGVkBtYt8z1R1/jQALWim3kV7CudlqH9npwr6TxT8sS wDZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1766046875; x=1766651675; 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=zGm2YYLVF+NHRLQ/f0+pGaC5F7muCq47qD8Hd3HU+QA=; b=iE3FRl2esagFv0T9cIQzXQHAeyJrBIDv5QS+v7dfX8ylUYqBJqx4dbEc79BnOl1ZNl +5aSrQlhrSizg2QhWFVxKIT+0hZsO/s3Up9AT4Nu+IjAr0r6LB14CZmC61GHM46eWaqP 1x8BtEYBFlYie8nTPKUg3aAmIsR2j5AY0tWGqE94Xd+w/o4fu5BYmZ/jvlTqCzWD5wpk XaL6wikZlS3bEur2pRlJkxqsumxQmmIunwlQ4Po0v1GDXd10xvrQaZKNoO2EZTbGcD3Q 4P9Uy5Eme+vGp92Q+83yvSFNy04Qyvmu4zDsyUWMK6yZIQK6LGvegW2T8fBM8hkUYF7C O4Mw== X-Forwarded-Encrypted: i=1; AJvYcCV93Fn4RD4ePzF8j3ohu9hjsnfBItmdfl7z8gn3dOZFFqHy1hqrS3A+yqRAAiEHXhf/bYEpbrmFGg==@vger.kernel.org X-Gm-Message-State: AOJu0YxziJp4Jcs5aYafB4KTP5JfbWtNti0hQLI+9tQeJVFFzXKhDBlw woN6mFsHKrcbuhgfGlP781gQJLWXybuEF1OkN0+P25b8yvVa/Xlqz5db X-Gm-Gg: AY/fxX5hvEwBeGARIKz2W2zXco7KXiwAnHHUCB8PWPvRDTgnVTBLtdaTu2I5Zodd/a9 +eK0oxOsmbvKK6kg1LOBPhCIxF4udlYFs0F2xme9Efx3e3aKZZa58Nj7cKzDH3jGZAd7AifodNg wR8XN7ropzKf8kGMuMD7S083NwgqmAXCGsyQ3LF7pnj/h2PPz+UrCPAE1XpJ/iJ7pOCT7/TnUK1 7/NVXygzikEtAmDvr7+EPOlsF/60/mAtoa7196cuxO0vQk9dPQ3nJOVqczFkoXdUdsveQ7qiEWK C1YrTni8Qr9az2RwNYLofx6H8mG9TnMwUgUldzhOlVhKXle3RYRFXJtXTAMxiesWVawdwGPOx8u fEh/vv/PtCfUDjt9GWt1tqWnXx0oaA+Rl7WSIcB4T35EEu80DR1FOwOFT5VhZ1D2IR2KrXpsVg4 jR58D5rEKFS4gxJ9YFkw== X-Google-Smtp-Source: AGHT+IG01Zh5Sj8Wpw60Y9qnB2rGkNf0VkStAE7zfoKr8x5fg0qT0m6qdMdO4p0UwgOn+i6lxzt3pg== X-Received: by 2002:a17:902:c94c:b0:2a0:d4e3:7181 with SMTP id d9443c01a7336-2a0d4e37ae0mr164872185ad.49.1766046875310; Thu, 18 Dec 2025 00:34:35 -0800 (PST) Received: from localhost ([2a03:2880:ff:49::]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2a2d1926cecsm17272995ad.74.2025.12.18.00.34.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Dec 2025 00:34:35 -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 01/25] io_uring/kbuf: refactor io_buf_pbuf_register() logic into generic helpers Date: Thu, 18 Dec 2025 00:32:55 -0800 Message-ID: <20251218083319.3485503-2-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 Refactor the logic in io_register_pbuf_ring() into generic helpers: - io_validate_buf_reg(): Validate user input and buffer registration parameters - io_alloc_new_buffer_list(): Allocate and initialize a new buffer list for the given buffer group ID - io_setup_pbuf_ring(): Sets up the physical buffer ring region and handles memory mapping for provided buffer rings This is a preparatory change for upcoming kernel-managed buffer ring support which will need to reuse some of these helpers. Signed-off-by: Joanne Koong --- io_uring/kbuf.c | 123 ++++++++++++++++++++++++++++++++---------------- 1 file changed, 82 insertions(+), 41 deletions(-) diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index 796d131107dd..100367bb510b 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -596,55 +596,71 @@ int io_manage_buffers_legacy(struct io_kiocb *req, unsigned int issue_flags) return IOU_COMPLETE; } -int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) +static int io_validate_buf_reg(struct io_uring_buf_reg *reg, + unsigned int permitted_flags) { - struct io_uring_buf_reg reg; - struct io_buffer_list *bl; - struct io_uring_region_desc rd; - struct io_uring_buf_ring *br; - unsigned long mmap_offset; - unsigned long ring_size; - int ret; - - lockdep_assert_held(&ctx->uring_lock); - - if (copy_from_user(®, arg, sizeof(reg))) - return -EFAULT; - if (!mem_is_zero(reg.resv, sizeof(reg.resv))) + if (!mem_is_zero(reg->resv, sizeof(reg->resv))) return -EINVAL; - if (reg.flags & ~(IOU_PBUF_RING_MMAP | IOU_PBUF_RING_INC)) + if (reg->flags & ~permitted_flags) return -EINVAL; - if (!is_power_of_2(reg.ring_entries)) + if (!is_power_of_2(reg->ring_entries)) return -EINVAL; /* cannot disambiguate full vs empty due to head/tail size */ - if (reg.ring_entries >= 65536) + if (reg->ring_entries >= 65536) return -EINVAL; + return 0; +} - bl = io_buffer_get_list(ctx, reg.bgid); - if (bl) { +static int io_alloc_new_buffer_list(struct io_ring_ctx *ctx, + struct io_uring_buf_reg *reg, + struct io_buffer_list **bl) +{ + struct io_buffer_list *list; + + list = io_buffer_get_list(ctx, reg->bgid); + if (list) { /* if mapped buffer ring OR classic exists, don't allow */ - if (bl->flags & IOBL_BUF_RING || !list_empty(&bl->buf_list)) + if (list->flags & IOBL_BUF_RING || !list_empty(&list->buf_list)) return -EEXIST; - io_destroy_bl(ctx, bl); + io_destroy_bl(ctx, list); } - bl = kzalloc(sizeof(*bl), GFP_KERNEL_ACCOUNT); - if (!bl) + list = kzalloc(sizeof(*list), GFP_KERNEL_ACCOUNT); + if (!list) return -ENOMEM; - mmap_offset = (unsigned long)reg.bgid << IORING_OFF_PBUF_SHIFT; - ring_size = flex_array_size(br, bufs, reg.ring_entries); + list->nr_entries = reg->ring_entries; + list->mask = reg->ring_entries - 1; + list->flags = IOBL_BUF_RING; + + *bl = list; + + return 0; +} + +static int io_setup_pbuf_ring(struct io_ring_ctx *ctx, + struct io_uring_buf_reg *reg, + struct io_buffer_list *bl) +{ + struct io_uring_region_desc rd; + unsigned long mmap_offset; + unsigned long ring_size; + int ret; + + mmap_offset = (unsigned long)reg->bgid << IORING_OFF_PBUF_SHIFT; + ring_size = flex_array_size(bl->buf_ring, bufs, reg->ring_entries); memset(&rd, 0, sizeof(rd)); rd.size = PAGE_ALIGN(ring_size); - if (!(reg.flags & IOU_PBUF_RING_MMAP)) { - rd.user_addr = reg.ring_addr; + if (!(reg->flags & IOU_PBUF_RING_MMAP)) { + rd.user_addr = reg->ring_addr; rd.flags |= IORING_MEM_REGION_TYPE_USER; } + ret = io_create_region(ctx, &bl->region, &rd, mmap_offset); if (ret) - goto fail; - br = io_region_get_ptr(&bl->region); + return ret; + bl->buf_ring = io_region_get_ptr(&bl->region); #ifdef SHM_COLOUR /* @@ -656,25 +672,50 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) * should use IOU_PBUF_RING_MMAP instead, and liburing will handle * this transparently. */ - if (!(reg.flags & IOU_PBUF_RING_MMAP) && - ((reg.ring_addr | (unsigned long)br) & (SHM_COLOUR - 1))) { - ret = -EINVAL; - goto fail; + if (!(reg->flags & IOU_PBUF_RING_MMAP) && + ((reg->ring_addr | (unsigned long)bl->buf_ring) & + (SHM_COLOUR - 1))) { + io_free_region(ctx->user, &bl->region); + return -EINVAL; } #endif - bl->nr_entries = reg.ring_entries; - bl->mask = reg.ring_entries - 1; - bl->flags |= IOBL_BUF_RING; - bl->buf_ring = br; + return 0; +} + +int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) +{ + unsigned int permitted_flags; + struct io_uring_buf_reg reg; + struct io_buffer_list *bl; + int ret; + + lockdep_assert_held(&ctx->uring_lock); + + if (copy_from_user(®, arg, sizeof(reg))) + return -EFAULT; + + permitted_flags = IOU_PBUF_RING_MMAP | IOU_PBUF_RING_INC; + ret = io_validate_buf_reg(®, permitted_flags); + if (ret) + return ret; + + ret = io_alloc_new_buffer_list(ctx, ®, &bl); + if (ret) + return ret; + + ret = io_setup_pbuf_ring(ctx, ®, bl); + if (ret) { + kfree(bl); + return ret; + } + if (reg.flags & IOU_PBUF_RING_INC) bl->flags |= IOBL_INC; + io_buffer_add_list(ctx, bl, reg.bgid); + return 0; -fail: - io_free_region(ctx->user, &bl->region); - kfree(bl); - return ret; } int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) -- 2.47.3