From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-op-o15.zoho.com (sender4-op-o15.zoho.com [136.143.188.15]) (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 0CB343815D1; Thu, 26 Feb 2026 02:57:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.15 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772074659; cv=pass; b=oJKRF7DvPt4SPTwRqKQgP0FbVDhfTiS5rn1Nwf0Yh1MQu5UEDRl60/1SRLmZxVyOVs2WOf4WXcZYMDOIO4ZldxgSmb085I0yHEQjyZrVHY7ARKVtYUhJVMCVkO0eLUYrPZS53kCB2BSsvTLHK5TjOQrMKL7ovVZckrw+G2TxvRs= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772074659; c=relaxed/simple; bh=G5b72HfKWuXYwZ6VlnHYS1xuLZTAW5LrQw5mObxUPm4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mASStEulyjg8WA7iece6y6F1HwjMxDsQ8Df7k84TeZJOFhy6iSDTd1KzdjnaWWmfPiHrXEFiUIPs+Ru6icIuaOPpD7WYP78+9iYSxLBORw14ErZJf7N8DchcB0Qpno8+X2gd3WDepEBRrsoiW0EsVEWRbsf5FYHYCAXD1mX+0dw= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.beauty; spf=pass smtp.mailfrom=linux.beauty; dkim=pass (1024-bit key) header.d=linux.beauty header.i=me@linux.beauty header.b=Pzp+aac2; arc=pass smtp.client-ip=136.143.188.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.beauty Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.beauty Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.beauty header.i=me@linux.beauty header.b="Pzp+aac2" ARC-Seal: i=1; a=rsa-sha256; t=1772074653; cv=none; d=zohomail.com; s=zohoarc; b=fe1e9zUixitXwPn64G7HAbbul6e/G2HOnMq4Fp8AVQKeCQV9yBruYUmFJK4nmvYeijOWNqRlo0y2D9nR+sRrObHC3eGhPCe0p+uG30w1C/CoqoRE21eLO6RbaUlhyIUOb5QRlgTemfM/ZCTh0+h2jx8JXGfW7cCTczmLC9NEhiA= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1772074653; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=NGwdvopqV5dpjItLDiwWZsiiVWpt8I+LlteAlx+Vpso=; b=L9GfOtsJNTDkTk5fzoVfoYPvDoatpEb60TvsjUtRFbhrYV+Nh6hIhV0M9TcSSVKYGt2CgpnDfGlNzGMlx6IMw/4fKsCTetJ6278X9Cr+pOoEChuGq2BG4cf2V/0C3KcBI3AIbKPZlWF6+pVVomggZYgVazkplAG8iumfd0Ajmi4= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=linux.beauty; spf=pass smtp.mailfrom=me@linux.beauty; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1772074653; s=zmail; d=linux.beauty; i=me@linux.beauty; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=NGwdvopqV5dpjItLDiwWZsiiVWpt8I+LlteAlx+Vpso=; b=Pzp+aac24AKPxNy4ykwRT7p/B1a5E3ZH9Cu1jfUwFW8v4Wx+bnihRaPfaS20xoSR Eztx6R9tA86fnw5vNwiuhy47EvUBy0g+PV7V+drUT9dcWzj1n6zEEmhrN6NCVvFxj80 OU8otqcWvpuY/htODiL7JuBlPGFd5K9Nev7mRrbE= Received: by mx.zohomail.com with SMTPS id 1772074650605524.6827548090777; Wed, 25 Feb 2026 18:57:30 -0800 (PST) From: Li Chen To: Pankaj Gupta , Dan Williams , Vishal Verma , Dave Jiang , Ira Weiny , virtualization@lists.linux.dev, nvdimm@lists.linux.dev, linux-kernel@vger.kernel.org Cc: Li Chen Subject: [PATCH v3 1/5] nvdimm: virtio_pmem: always wake -ENOSPC waiters Date: Thu, 26 Feb 2026 10:57:06 +0800 Message-ID: <20260226025712.2236279-2-me@linux.beauty> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260226025712.2236279-1-me@linux.beauty> References: <20260226025712.2236279-1-me@linux.beauty> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-ZohoMailClient: External virtio_pmem_host_ack() reclaims virtqueue descriptors with virtqueue_get_buf(). The -ENOSPC waiter wakeup is tied to completing the returned token. If token completion is skipped for any reason, reclaimed descriptors may not wake a waiter and the submitter may sleep forever waiting for a free slot. Always wake one -ENOSPC waiter for each virtqueue completion before touching the returned token. Signed-off-by: Li Chen --- v2->v3: - Split out the waiter wakeup ordering change from READ_ONCE()/WRITE_ONCE() updates (now patch 2/5), per Pankaj's suggestion. drivers/nvdimm/nd_virtio.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c index af82385be7c6..a1ad8d67ad2d 100644 --- a/drivers/nvdimm/nd_virtio.c +++ b/drivers/nvdimm/nd_virtio.c @@ -9,26 +9,33 @@ #include "virtio_pmem.h" #include "nd.h" +static void virtio_pmem_wake_one_waiter(struct virtio_pmem *vpmem) +{ + struct virtio_pmem_request *req_buf; + + if (list_empty(&vpmem->req_list)) + return; + + req_buf = list_first_entry(&vpmem->req_list, + struct virtio_pmem_request, list); + req_buf->wq_buf_avail = true; + wake_up(&req_buf->wq_buf); + list_del(&req_buf->list); +} + /* The interrupt handler */ void virtio_pmem_host_ack(struct virtqueue *vq) { struct virtio_pmem *vpmem = vq->vdev->priv; - struct virtio_pmem_request *req_data, *req_buf; + struct virtio_pmem_request *req_data; unsigned long flags; unsigned int len; spin_lock_irqsave(&vpmem->pmem_lock, flags); while ((req_data = virtqueue_get_buf(vq, &len)) != NULL) { + virtio_pmem_wake_one_waiter(vpmem); req_data->done = true; wake_up(&req_data->host_acked); - - if (!list_empty(&vpmem->req_list)) { - req_buf = list_first_entry(&vpmem->req_list, - struct virtio_pmem_request, list); - req_buf->wq_buf_avail = true; - wake_up(&req_buf->wq_buf); - list_del(&req_buf->list); - } } spin_unlock_irqrestore(&vpmem->pmem_lock, flags); } -- 2.52.0