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 CEDD23BB9F3 for ; Mon, 31 Aug 2026 18:30:05 +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=1788201007; cv=none; b=KI5jRt3JXXJPq6M7Ys87ULilJlx9I6kknxTkSOAzz5q0I/P4wBusrjVfX6g3Mk6bM/MdwbSYh21AHQSfVMNcQApsArb5iBEM2lCLbiItrGVKH+MrhW8+362i3R7N7SKrUe2EPl4W1uVc/X/ecGKZ58trZr4KqcXD0raNKN7IG+4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788201007; c=relaxed/simple; bh=M7wvg3m5W+10SWmBXFSMNSrargExtq6wC7CsCshS1SQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pAYuSPDc9WLy0T6naqWInS2H3BXyWlAk/I+5PgNIhNfjG3zwQmoqHS392U1oYdH83guot5brFfS5j8dyJK7+qaBQE4wguKcIyC2jOlGS8VTtMxFH9SLuSENaI4IPSZzHwkD+PlLe48Cxf9/s26/rJCrLBadeujU1+8Oao0Laq34= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ol8sMBhh; 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="Ol8sMBhh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF2ED1F000E9; Mon, 31 Aug 2026 18:30:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788201005; bh=dgJjHhe4Fz/zBeIwS3RW4EUTx8Yn4UxWhvXPuJojrmc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ol8sMBhhUm6IxMnfcf8ngvHSHtO5ObEdACM4oXgyfjPxxXvTHXVVwSGevJT1OIeOR I1+ApwbmHuV8W3By5lLA1w7wfLk2/925KTUcBMzKrvh5XZkQZAE6B2S5lnwfEuxOL/ 17nIwNeCgOqhNqaFMxNgDIdsaT+WVA+k0r9xVciThj5mvhRbR544TiXW80TlJn5TgL Yq2IfAAkEEgQ5+bt96z5yeOAU7JyVOqk6VjuslMzDll7kyoxyA5ns7g0gMdPxmYdOi 10/xVie37317WHLl2k/uE0vGnDP3h4X4EA1ajKsLKRkcUv5fwcnWrbfYZplpMxPSIV 7JipYkgjWlsJg== From: Sasha Levin To: stable@vger.kernel.org Cc: Joanne Koong , Bernd Schubert , Miklos Szeredi , Sasha Levin Subject: [PATCH 7.2.y 1/2] fuse: decouple fuse_ring creation from ent registration Date: Mon, 31 Aug 2026 14:30:01 -0400 Message-ID: <20260831183002.1670211-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026083141-juicy-elated-cee2@gregkh> References: <2026083141-juicy-elated-cee2@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Joanne Koong [ Upstream commit 6330b1f61ed1d17850fc61bdb8920ca1056e2cf9 ] Currently, the connection's fuse_ring is created lazily on the first FUSE_IO_URING_CMD_REGISTER command. A server registers entries from one thread per queue (one per CPU) and those threads issue their first REGISTER command concurrently. They then race to create the single per-connection fuse_ring, which required open-coded handling in fuse_uring_create() to detect and protect against concurrent creations. Decouple fuse_ring creation from ent registration and move it to FUSE_INIT reply processing after a server has negotiated and set FUSE_OVER_IO_URING. The ring is published before the connection is marked initialized. fuse_uring_register() no longer creates the ring and it instead uses the ring set up at init time. Reviewed-by: Bernd Schubert Signed-off-by: Joanne Koong Signed-off-by: Miklos Szeredi Stable-dep-of: fd10f40af314 ("fuse: copy request headers via a stack buffer for io-uring") Signed-off-by: Sasha Levin --- fs/fuse/dev.c | 8 +++----- fs/fuse/dev.h | 2 +- fs/fuse/dev_uring.c | 26 ++++++++++---------------- fs/fuse/dev_uring_i.h | 5 +++++ fs/fuse/inode.c | 4 +++- 5 files changed, 22 insertions(+), 23 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 5763a7cd3b37f..9ab1f1f551ce0 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -75,6 +75,9 @@ void fuse_chan_set_initialized(struct fuse_chan *fch, struct fuse_chan_param *pa fch->minor = param->minor; fch->max_write = param->max_write; fch->max_pages = param->max_pages; + + if (param->io_uring_enabled) + fuse_uring_conn_init(fch); } /* Make sure stores before this are seen on another CPU */ @@ -411,11 +414,6 @@ void fuse_chan_set_fc(struct fuse_chan *fch, struct fuse_conn *fc) fch->conn = fc; } -void fuse_chan_io_uring_enable(struct fuse_chan *fch) -{ - fch->io_uring = 1; -} - void fuse_pqueue_init(struct fuse_pqueue *fpq) { spin_lock_init(&fpq->lock); diff --git a/fs/fuse/dev.h b/fs/fuse/dev.h index aed69fd14c41d..8d25378c09183 100644 --- a/fs/fuse/dev.h +++ b/fs/fuse/dev.h @@ -22,6 +22,7 @@ struct fuse_chan_param { unsigned int minor; unsigned int max_write; unsigned int max_pages; + bool io_uring_enabled; }; struct fuse_chan *fuse_chan_new(void); @@ -34,7 +35,6 @@ void fuse_chan_max_background_set(struct fuse_chan *fch, unsigned int val); unsigned int fuse_chan_num_waiting(struct fuse_chan *fch); void fuse_chan_set_fc(struct fuse_chan *fch, struct fuse_conn *fc); void fuse_chan_set_initialized(struct fuse_chan *fch, struct fuse_chan_param *param); -void fuse_chan_io_uring_enable(struct fuse_chan *fch); ssize_t fuse_chan_send(struct fuse_chan *fch, struct fuse_args *args); int fuse_chan_send_bg(struct fuse_chan *fch, struct fuse_args *args, gfp_t gfp_flags); int fuse_chan_send_notify_reply(struct fuse_chan *fch, struct fuse_args *args, u64 unique); diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c index 77c8cec43d9c6..55e0ecdb20582 100644 --- a/fs/fuse/dev_uring.c +++ b/fs/fuse/dev_uring.c @@ -238,7 +238,6 @@ static struct fuse_ring *fuse_uring_create(struct fuse_chan *fch) { struct fuse_ring *ring; size_t nr_queues = num_possible_cpus(); - struct fuse_ring *res = NULL; size_t max_payload_size; ring = kzalloc_obj(*ring, GFP_KERNEL_ACCOUNT); @@ -258,12 +257,6 @@ static struct fuse_ring *fuse_uring_create(struct fuse_chan *fch) spin_unlock(&fch->lock); goto out_err; } - if (fch->ring) { - /* race, another thread created the ring in the meantime */ - spin_unlock(&fch->lock); - res = fch->ring; - goto out_err; - } init_waitqueue_head(&ring->stop_waitq); @@ -278,7 +271,13 @@ static struct fuse_ring *fuse_uring_create(struct fuse_chan *fch) out_err: kfree(ring->queues); kfree(ring); - return res; + return NULL; +} + +void fuse_uring_conn_init(struct fuse_chan *fch) +{ + if (fuse_uring_create(fch)) + fch->io_uring = 1; } static struct fuse_ring_queue *fuse_uring_create_queue(struct fuse_ring *ring, @@ -1176,15 +1175,10 @@ static int fuse_uring_register(struct io_uring_cmd *cmd, struct fuse_ring *ring = smp_load_acquire(&fch->ring); struct fuse_ring_queue *queue; struct fuse_ring_ent *ent; - int err; unsigned int qid = READ_ONCE(cmd_req->qid); - err = -ENOMEM; - if (!ring) { - ring = fuse_uring_create(fch); - if (!ring) - return err; - } + if (!ring) + return -EINVAL; if (qid >= ring->nr_queues) { pr_info_ratelimited("fuse: Invalid ring qid %u\n", qid); @@ -1195,7 +1189,7 @@ static int fuse_uring_register(struct io_uring_cmd *cmd, if (!queue) { queue = fuse_uring_create_queue(ring, qid); if (!queue) - return err; + return -ENOMEM; } /* diff --git a/fs/fuse/dev_uring_i.h b/fs/fuse/dev_uring_i.h index 55f8d04e4b0b2..d721a4fc0215c 100644 --- a/fs/fuse/dev_uring_i.h +++ b/fs/fuse/dev_uring_i.h @@ -135,6 +135,7 @@ struct fuse_ring { bool ready; }; +void fuse_uring_conn_init(struct fuse_chan *fch); void fuse_uring_stop_queues(struct fuse_ring *ring); void fuse_uring_abort_end_requests(struct fuse_ring *ring); int fuse_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags); @@ -174,6 +175,10 @@ static inline bool fuse_uring_ready(struct fuse_chan *fch) #else /* CONFIG_FUSE_IO_URING */ +static inline void fuse_uring_conn_init(struct fuse_chan *fch) +{ +} + static inline void fuse_uring_abort(struct fuse_chan *fch) { } diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index d975073c60296..ce4891a04a378 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1272,6 +1272,7 @@ static void process_init_reply(struct fuse_args *args, int error) struct fuse_mount *fm = ia->fm; struct fuse_conn *fc = fm->fc; struct fuse_init_out *arg = &ia->out; + bool io_uring_enabled = false; bool ok = true; if (error || arg->major != FUSE_KERNEL_VERSION) @@ -1402,7 +1403,7 @@ static void process_init_reply(struct fuse_args *args, int error) ok = false; } if (flags & FUSE_OVER_IO_URING && fuse_uring_enabled()) - fuse_chan_io_uring_enable(fc->chan); + io_uring_enabled = true; if (flags & FUSE_REQUEST_TIMEOUT) timeout = arg->request_timeout; @@ -1432,6 +1433,7 @@ static void process_init_reply(struct fuse_args *args, int error) .minor = fc->minor, .max_write = fc->max_write, .max_pages = fc->max_pages, + .io_uring_enabled = io_uring_enabled, }; fuse_chan_set_initialized(fc->chan, &cp); } -- 2.53.0