From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f52.google.com (mail-wr1-f52.google.com [209.85.221.52]) (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 36E7837EFFF for ; Wed, 29 Apr 2026 15:26:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777476407; cv=none; b=CMJKnI3BQkjKLzFEdXReCQENkcMdIncz1bou+8jfeC+g61qn1c1xBtFcll2I8vBorUk4B2l1JlUG2CASDXT3uwUEtLUBuxbivqaKUbU8CUbLgY9i52wMkKXh3iZhr2PPZoxpzvBEjqx7LRJLttiwGZszAScX5D5CuA763Q8CwJQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777476407; c=relaxed/simple; bh=wPna77yg1sN41atnG+TaUrGkyr7sGycheND1pjkgNrA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OyBBWJW0qSqhG8yW1vOG7Z/fP98EdoK/4PN0Vdk3Rmd6yyZaazi/18frLEcBm9QrLE1cpBn0Bi3tYBqTHpJA7+2v9bQm1NYvY2F/ymGV/wyGyArUD1ePuM7pr6uCVaDF8zSFVJqrBMk/EjHO4JxItMoI7fq8dJLYPw0V7tNmBKU= 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=TY6XL8+S; arc=none smtp.client-ip=209.85.221.52 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="TY6XL8+S" Received: by mail-wr1-f52.google.com with SMTP id ffacd0b85a97d-43cfde3c3f3so12742234f8f.3 for ; Wed, 29 Apr 2026 08:26:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1777476402; x=1778081202; 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=swjDqvfsydtMCDgC1VH/dViD3xm2NdukCe3jlmQ9xuA=; b=TY6XL8+SopWnzYIn0SbdzNv5g86pO9n5+v3Cvu0qi5bOnGzBX7BxvB1PnP1RLoCH3P F8Ae4llxZwbHeUX/A6xvs0pPRBr8geA5jkkMMZ+u2oFGlYCIa/B5U/m8mkgiuDqZa2GT MRr3T7Tp38ZmmFAfACqOYpqY3vnQh1uFzHALigHNaRPEmChrY5tNXL0kMPWoWkaXtSB4 NGWN1G68pJTZ0anmuqdmk83WmK3e1OzREoLUjPSQAotRh87+OX1uG1MakOwNJMZqHnb6 98o+lgiWw98QvScr7M7vN4rUfbIwJHsQlwBCFT8SiKiNqiw0a/sxTBAEUAV4a7iwyCwP tqbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777476402; x=1778081202; 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=swjDqvfsydtMCDgC1VH/dViD3xm2NdukCe3jlmQ9xuA=; b=nLpP4HmyzhPnxHUBkF3C+6RvmgftYxSsIUFEMhhEOuGYkx5lSe4g0ZyD5/4ZVwk80G 16D8v9zxCnbd7o7l27u8BqyvLXDIiwsjgWjwOqHEM5O3zG/eC7As5Fw5SVx7NOft2ExZ j8IJF2vsAtfiQowUqctRTkng+P9K1t6EstdJRUo7jcCEWXZOB+TO0iYH5BULHQfvlcWq m6eHzDHMfLG1yRbi0gziGBkhZcTDr7wkhta4fYT6bo+5NI404JPNjshO3Wt3GLK3s8wT 83jdbPRSGq1KhHcrbEXcxR5CcR9dhz/R7lS+MKoLjX326yZdqwdghQU9wI4Uq5D1C76Q YdOw== X-Forwarded-Encrypted: i=1; AFNElJ9RCZn29BHk082PaMKoXJe7OZ69Do1LmHDSB7v39R/yIWnbIo1BX7il4ZAQqD0kdC3SOkki45IVAg==@vger.kernel.org X-Gm-Message-State: AOJu0YwDRawkmQORWvizieHXoMfaLcaqNt1BzjjR4ELHOrqSRmMa7PYE 6ZQOfoTGxWx5MNWkE7Gg09TrzQeQwiTtEkVlgo6rQpf5iU9QQgQue0gH X-Gm-Gg: AeBDieu0K6KsqWu2VUyJYkwdah6s3XDUhCgoBa44bp6lLo2ch4AEyYK7nQj5Os52qxc z03Z8WT+QJ3de/3SGaOwZJlURKfxfmlCRtdLq1Aj7QussPegCo3dWDrmwyE1aeYBpG/Ofy78mk8 lovn0sUy7sIL16JykC6qQQNDBQVMyIUP3Q3TH99cDwsr0SDpwPJglV3hKzKAlrQf4xa/ulj8Sif boEFqs5DuM4hCkL1BqDyi+PP5h0KVtYf6isI/jI0j6aFa6VEGqnGSY3NSx6e4EW+0BARZgPWXVb iGws+GL+pMHJ5P0U8jDsxvfcFXAS5wFhqHpmjHJtRLJtTtE3Zem9LWEyYoYs4kXqS3TLGx9Iyjr qjC1RyhpVDTcFzXIiUmV8Uw8cJtdvqGVaomY/xZCxo3FpyLxPZ43oiwbJ9nZJXsidSdzh6AZVsU ss1f77+xzyR+Ao4p/R2UkWsiHm8npAk+LG/9tHgDOZIsJbnTKj70lNmEblo7Fx92G1RvItxSY+D aTTQ1XNFS0H9H4jMfXlO/bgIvJUDcxmzea9dHgGAVCU X-Received: by 2002:a05:6000:1888:b0:43f:debd:feb1 with SMTP id ffacd0b85a97d-44649ba18b5mr14136832f8f.39.1777476397928; Wed, 29 Apr 2026 08:26:37 -0700 (PDT) Received: from 127.0.0.1localhost ([82.132.184.31]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-447b76e5c22sm6382951f8f.28.2026.04.29.08.26.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Apr 2026 08:26:37 -0700 (PDT) From: Pavel Begunkov To: Jens Axboe , Keith Busch , Christoph Hellwig , Sagi Grimberg , Alexander Viro , Christian Brauner , Andrew Morton , Sumit Semwal , =?UTF-8?q?Christian=20K=C3=B6nig?= , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org Cc: asml.silence@gmail.com, Nitesh Shetty , Kanchan Joshi , Anuj Gupta , Tushar Gohad , William Power , Phil Cayton , Jason Gunthorpe Subject: [PATCH v3 04/10] block: introduce dma map backed bio type Date: Wed, 29 Apr 2026 16:25:50 +0100 Message-ID: <646ecd6fde8d9e146cb051efb514deb27ce3883e.1777475843.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Premapped buffers don't require a generic bio_vec since these have already been dma mapped. Repurpose the bi_io_vec space to strore dmabuf maps as they are mutually exclusive. Suggested-by: Keith Busch Signed-off-by: Pavel Begunkov --- block/bio.c | 25 ++++++++++++++++++++++++- block/blk-merge.c | 14 ++++++++++++++ block/blk.h | 3 ++- block/fops.c | 2 ++ include/linux/bio.h | 19 ++++++++++++++++--- include/linux/blk_types.h | 8 +++++++- 6 files changed, 65 insertions(+), 6 deletions(-) diff --git a/block/bio.c b/block/bio.c index 0734b50d4992..bdc91777c288 100644 --- a/block/bio.c +++ b/block/bio.c @@ -851,7 +851,13 @@ static int __bio_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp) bio->bi_write_hint = bio_src->bi_write_hint; bio->bi_write_stream = bio_src->bi_write_stream; bio->bi_iter = bio_src->bi_iter; - bio->bi_io_vec = bio_src->bi_io_vec; + + if (!bio_flagged(bio_src, BIO_DMABUF_MAP)) { + bio->bi_io_vec = bio_src->bi_io_vec; + } else { + bio->dmabuf_map = bio_src->dmabuf_map; + bio_set_flag(bio, BIO_DMABUF_MAP); + } if (bio->bi_bdev) { if (bio->bi_bdev == bio_src->bi_bdev && @@ -1183,6 +1189,18 @@ void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter) bio_set_flag(bio, BIO_CLONED); } +void bio_dmabuf_map_set(struct bio *bio, struct iov_iter *iter) +{ + WARN_ON_ONCE(bio->bi_max_vecs); + + bio->dmabuf_map = iter->dmabuf_map; + bio->bi_vcnt = 0; + bio->bi_iter.bi_bvec_done = iter->iov_offset; + bio->bi_iter.bi_size = iov_iter_count(iter); + bio->bi_opf |= REQ_NOMERGE; + bio_set_flag(bio, BIO_DMABUF_MAP); +} + /* * Aligns the bio size to the len_align_mask, releasing excessive bio vecs that * __bio_iov_iter_get_pages may have inserted, and reverts the trimmed length @@ -1252,6 +1270,11 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter, iov_iter_advance(iter, bio->bi_iter.bi_size); return 0; } + if (iov_iter_is_dmabuf_map(iter)) { + bio_dmabuf_map_set(bio, iter); + iov_iter_advance(iter, bio->bi_iter.bi_size); + return 0; + } if (iov_iter_extract_will_pin(iter)) bio_set_flag(bio, BIO_PAGE_PINNED); diff --git a/block/blk-merge.c b/block/blk-merge.c index fcf09325b22e..fc2c0c428001 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -348,6 +348,19 @@ int bio_split_io_at(struct bio *bio, const struct queue_limits *lim, len_align_mask |= (bc->bc_key->crypto_cfg.data_unit_size - 1); } + if (bio_flagged(bio, BIO_DMABUF_MAP)) { + nsegs = 1; + + if ((bio->bi_iter.bi_bvec_done & lim->dma_alignment) || + (bio->bi_iter.bi_size & len_align_mask)) + return -EINVAL; + if (bio->bi_iter.bi_size > max_bytes) { + bytes = max_bytes; + goto split; + } + goto out; + } + bio_for_each_bvec(bv, bio, iter) { if (bv.bv_offset & start_align_mask || bv.bv_len & len_align_mask) @@ -378,6 +391,7 @@ int bio_split_io_at(struct bio *bio, const struct queue_limits *lim, bvprvp = &bvprv; } +out: *segs = nsegs; bio->bi_bvec_gap_bit = ffs(gaps); return 0; diff --git a/block/blk.h b/block/blk.h index b998a7761faf..b4b09abebce8 100644 --- a/block/blk.h +++ b/block/blk.h @@ -424,7 +424,8 @@ static inline struct bio *__bio_split_to_limits(struct bio *bio, switch (bio_op(bio)) { case REQ_OP_READ: case REQ_OP_WRITE: - if (bio_may_need_split(bio, lim)) + if (bio_may_need_split(bio, lim) || + bio_flagged(bio, BIO_DMABUF_MAP)) return bio_split_rw(bio, lim, nr_segs); *nr_segs = 1; return bio; diff --git a/block/fops.c b/block/fops.c index bb6642b45937..713a3ba3f457 100644 --- a/block/fops.c +++ b/block/fops.c @@ -349,6 +349,8 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, * bio_iov_iter_get_pages() and set the bvec directly. */ bio_iov_bvec_set(bio, iter); + } else if (iov_iter_is_dmabuf_map(iter)) { + bio_dmabuf_map_set(bio, iter); } else { ret = blkdev_iov_iter_get_pages(bio, iter, bdev); if (unlikely(ret)) diff --git a/include/linux/bio.h b/include/linux/bio.h index 97d747320b35..0c43fa6b0900 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -108,16 +108,26 @@ static inline bool bio_next_segment(const struct bio *bio, #define bio_for_each_segment_all(bvl, bio, iter) \ for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); ) +static inline void bio_advance_iter_dmabuf_map(struct bvec_iter *iter, + unsigned int bytes) +{ + iter->bi_bvec_done += bytes; + iter->bi_size -= bytes; +} + static inline void bio_advance_iter(const struct bio *bio, struct bvec_iter *iter, unsigned int bytes) { iter->bi_sector += bytes >> 9; - if (bio_no_advance_iter(bio)) + if (bio_no_advance_iter(bio)) { iter->bi_size -= bytes; - else + } else if (bio_flagged(bio, BIO_DMABUF_MAP)) { + bio_advance_iter_dmabuf_map(iter, bytes); + } else { bvec_iter_advance(bio->bi_io_vec, iter, bytes); /* TODO: It is reasonable to complete bio with error here. */ + } } /* @bytes should be less or equal to bvec[i->bi_idx].bv_len */ @@ -129,6 +139,8 @@ static inline void bio_advance_iter_single(const struct bio *bio, if (bio_no_advance_iter(bio)) iter->bi_size -= bytes; + else if (bio_flagged(bio, BIO_DMABUF_MAP)) + bio_advance_iter_dmabuf_map(iter, bytes); else bvec_iter_advance_single(bio->bi_io_vec, iter, bytes); } @@ -391,7 +403,7 @@ static inline void bio_wouldblock_error(struct bio *bio) */ static inline int bio_iov_vecs_to_alloc(struct iov_iter *iter, int max_segs) { - if (iov_iter_is_bvec(iter)) + if (iov_iter_is_bvec(iter) || iov_iter_is_dmabuf_map(iter)) return 0; return iov_iter_npages(iter, max_segs); } @@ -471,6 +483,7 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter, unsigned len_align_mask); void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter); +void bio_dmabuf_map_set(struct bio *bio, struct iov_iter *iter); void __bio_release_pages(struct bio *bio, bool mark_dirty); extern void bio_set_pages_dirty(struct bio *bio); extern void bio_check_pages_dirty(struct bio *bio); diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 8808ee76e73c..d5ad085b701d 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -233,7 +233,12 @@ struct bio { atomic_t __bi_remaining; /* The actual vec list, preserved by bio_reset() */ - struct bio_vec *bi_io_vec; + union { + struct bio_vec *bi_io_vec; + /* Driver specific dma map, present only with BIO_DMABUF_MAP */ + struct io_dmabuf_map *dmabuf_map; + }; + struct bvec_iter bi_iter; union { @@ -322,6 +327,7 @@ enum { BIO_REMAPPED, BIO_ZONE_WRITE_PLUGGING, /* bio handled through zone write plugging */ BIO_EMULATES_ZONE_APPEND, /* bio emulates a zone append operation */ + BIO_DMABUF_MAP, /* Using premmaped dma buffers */ BIO_FLAG_LAST }; -- 2.53.0