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 E282A12FF69; Sat, 4 Jul 2026 19:52:47 +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=1783194769; cv=none; b=SuCXRMZ7LMNbQt+QxA8fGiteVn51SHeNHV18Fe0HMaIQb4GZoq/3GtYTNLVpUwncNFJtYgd+O8x8X0cbeEnsTRU21cg6kNaTeY9fNfKcFM+XyDBec22RNgC/kpvyulqA35nPsszIgnQI9ghnUMDcHpFS76fhgv+u55ruRhy8V4A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783194769; c=relaxed/simple; bh=mTow1tmrdP9XeBM1b31QKMHtfH2seK9YXYtGLsyFW8M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Dnga2I3PNeT/RiwLTDDAkERknqhtHV5Lzhb6fjfs17Iq7Q1awt7aHV7C+sOZypn9vKrjackTLBCWX8bgd8MtOvok35tj431o+h8BC2+guZQhQkAC6+QoEorihiGyjtQOrG4WWPXVHQlQtQKzDDdVooW+UmpHDddiACqyjENliAI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K4lNN0dG; 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="K4lNN0dG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E73361F000E9; Sat, 4 Jul 2026 19:52:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783194767; bh=mXJiwwaeOWgN5pHsCgD632laX9hPGfy7GVg2b2/T7js=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=K4lNN0dGzzywNRxaL6RbtTbW0krF8yl7KvNm1psx9S8v+EoFuxPY356jqfIV6HtoT MRluYXHFNTfis30lYXNmexdz9HdrBxACIAIDGZpGXI/cko4cY0p+fvUq+dfd9OyHIS kpqjkeT6Di+7DaVQJ3V9SZ8QxhwJXmMKwewHuS+ljc7PMoDVi6RlrDpgwTSnsPkvvS Rw58JYOrk0fQHEuk1f6ps4AbBYosAKE41/Oae2Bn0pXS782aD8g/AnCznb3ktD8dKl cXk/qoyh9YABGrlWysWaRk/IBvOJ5IPZKMtunTfBT5AUi9LMRjYb3V6SFzyay8NF3i veottqF8gIpqA== From: Yu Kuai To: Jens Axboe , Tejun Heo Cc: Christoph Hellwig , Keith Busch , Sagi Grimberg , Alasdair Kergon , Benjamin Marzinski , Mike Snitzer , Mikulas Patocka , Dongsheng Yang , Zheng Gu , Coly Li , Kent Overstreet , Josef Bacik , Yu Kuai , Nilay Shroff , linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-nvme@lists.infradead.org, dm-devel@lists.linux.dev, linux-bcache@vger.kernel.org Subject: [RFC PATCH v1 05/17] block: add bio_alloc_atomic() for atomic bio users Date: Sun, 5 Jul 2026 03:51:12 +0800 Message-ID: <20260704195124.1375075-6-yukuai@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260704195124.1375075-1-yukuai@kernel.org> References: <20260704195124.1375075-1-yukuai@kernel.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Yu Kuai Add bio_alloc_atomic() for callers that need a GFP_ATOMIC bio from the default bio set but cannot safely pass a bdev during allocation. The helper returns an unattached bio, leaving callers to set bi_bdev and attach blkcg state explicitly before submission. Use the helper for virtio-pmem flush child bios and OCFS2 heartbeat I/O. Both allocate bios from atomic paths and must avoid creating missing blkgs once blkg creation is protected by q->blkcg_mutex. virtio-pmem clones the parent bio's blkg association; OCFS2 binds heartbeat I/O to the root blkg. Signed-off-by: Yu Kuai --- drivers/nvdimm/nd_virtio.c | 8 ++++---- fs/ocfs2/cluster/heartbeat.c | 15 ++++++++++++--- include/linux/bio.h | 6 ++++++ 3 files changed, 22 insertions(+), 7 deletions(-) diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c index 4176046627be..13d1ed1c466c 100644 --- a/drivers/nvdimm/nd_virtio.c +++ b/drivers/nvdimm/nd_virtio.c @@ -115,13 +115,13 @@ int async_pmem_flush(struct nd_region *nd_region, struct bio *bio) * parent bio. Otherwise directly call nd_region flush. */ if (bio && bio->bi_iter.bi_sector != -1) { - struct bio *child = bio_alloc(bio->bi_bdev, 0, - REQ_OP_WRITE | REQ_PREFLUSH, - GFP_ATOMIC); + struct bio *child = bio_alloc_atomic(0, + REQ_OP_WRITE | REQ_PREFLUSH); if (!child) return -ENOMEM; - bio_clone_blkg_association(child, bio); + child->bi_bdev = bio->bi_bdev; + bio_clone_blkg_association(child, bio); child->bi_iter.bi_sector = -1; bio_chain(child, bio); submit_bio(child); diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c index d12784aaaa4b..ec70f3b62837 100644 --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -519,16 +520,24 @@ static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg, struct bio *bio; struct page *page; - /* Testing has shown this allocation to take long enough under + /* + * Testing has shown this allocation to take long enough under * GFP_KERNEL that the local node can get fenced. It would be * nicest if we could pre-allocate these bios and avoid this - * all together. */ - bio = bio_alloc(reg_bdev(reg), 16, opf, GFP_ATOMIC); + * all together. + * + * Use the atomic bio allocation helper so bio_init() does not create a + * missing blkg. Heartbeat IO is cluster-liveness IO, so account it to + * the root blkcg instead. + */ + bio = bio_alloc_atomic(16, opf); if (!bio) { mlog(ML_ERROR, "Could not alloc slots BIO!\n"); bio = ERR_PTR(-ENOMEM); goto bail; } + bio->bi_bdev = reg_bdev(reg); + bio_associate_blkg_from_css(bio, blkcg_root_css); /* Must put everything in 512 byte sectors for the bio... */ bio->bi_iter.bi_sector = (reg->hr_start_block + cs) << (bits - 9); diff --git a/include/linux/bio.h b/include/linux/bio.h index 8f33f717b14f..f7d94d37893f 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -366,6 +366,12 @@ static inline struct bio *bio_alloc(struct block_device *bdev, return bio_alloc_bioset(bdev, nr_vecs, opf, gfp_mask, &fs_bio_set); } +static inline struct bio *bio_alloc_atomic(unsigned short nr_vecs, + blk_opf_t opf) +{ + return bio_alloc_bioset(NULL, nr_vecs, opf, GFP_ATOMIC, &fs_bio_set); +} + void submit_bio(struct bio *bio); extern void bio_endio(struct bio *); -- 2.51.0