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 CEE9B2DBF75 for ; Fri, 11 Sep 2026 00:34:16 +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=1789086858; cv=none; b=jVSGrNBGoQhFzhOawuke34Z8MMeaLElbKZIZgouGkQpgFeuHa+s1/FRbKnxYkerwP/AJACmI4Crr7rQGyzpBOGEnWB+25lZhjmHFUU6nPqZZg3jK8UdprbMV58m3WxcUvTnALB9bKMdUbMlgSEJLZoKDJraXKC5FMy4+Gkr45wY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789086858; c=relaxed/simple; bh=X1RL8AUyyVVil2NDOMfO2QCmBD3+Nmt7PwD5Vs0m/+k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZJ6Z4lUYjNFDKECld0aCczAx+YdKeXxzkWjR5LjYk2IXK4A1ezC5o6OCLpWqxdf7GfzBCY7z4P9kOhDrrmvDacxVq+TaeTg9vmYyVtKMrOvseP9MLw9leVTbWt5oxJIAAtQ8shU7ofFuGrEUCalRT5Jo41REi7qcaW2CfymrISg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bwGq0/0f; 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="bwGq0/0f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E217E1F0089B; Fri, 11 Sep 2026 00:34:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789086855; bh=4E2hztJYEeFeiXB1CkuEtUKp+PIy+GXqC18biYHG258=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bwGq0/0fRlwxc8qzB30DdXcuT+cx2q+WYEkLrXUoOYLVBFIvnIFSgOKoUdk8IU4AL Zou2q5vCmQelRENFvNUpyXU7EadXpc/ZGRuaFNbp4dSb9Hr+Cnq9sdL1QE0Yk1/v46 TWjj0K7gvgFQjU6Pu/c7D5qtyN1SOkK+hwSvGGL/eAhmU+V6Bl4G5WTu10UilTE3Fh AkWeut68rKooR0miggbyAPaHyjAy6P1xvH/wswtsdOb4iqLCTVxJqIx7b8wiheSoSR DSjvLkB3YTeWIFIBXHX5wNQJ3fiYSaSe7q9oGJUC+u1US6NKj4QnYbMX+UeRY4i2H4 lcCjgmnR0DGww== From: Sasha Levin To: stable@vger.kernel.org Cc: Li Chen , Pankaj Gupta , "Michael S. Tsirkin" , Sasha Levin Subject: [PATCH 6.18.y 5/6] nvdimm: virtio_pmem: use READ_ONCE()/WRITE_ONCE() for wait flags Date: Thu, 10 Sep 2026 20:34:09 -0400 Message-ID: <20260911003410.3483414-5-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260911003410.3483414-1-sashal@kernel.org> References: <2026090938-reliance-nearly-8ed8@gregkh> <20260911003410.3483414-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Li Chen [ Upstream commit 08e72a5ba1ab9dc0adf993ff0f4d606a1e3445a8 ] Use READ_ONCE()/WRITE_ONCE() for the wait_event() flags (done and wq_buf_avail). They are observed by waiters without pmem_lock, so make the accesses explicit single loads/stores and avoid compiler reordering/caching across the wait/wake paths. Acked-by: Pankaj Gupta Signed-off-by: Li Chen Signed-off-by: Michael S. Tsirkin Message-ID: <20260630092338.2094628-8-me@linux.beauty> Stable-dep-of: e57140944b5a ("nvdimm: virtio_pmem: refcount requests for token lifetime") Signed-off-by: Sasha Levin --- drivers/nvdimm/nd_virtio.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/nvdimm/nd_virtio.c b/drivers/nvdimm/nd_virtio.c index 0ef8a7820fea2..2da6dc527552b 100644 --- a/drivers/nvdimm/nd_virtio.c +++ b/drivers/nvdimm/nd_virtio.c @@ -24,9 +24,9 @@ static void virtio_pmem_wake_one_waiter(struct virtio_pmem *vpmem) req_buf = list_first_entry(&vpmem->req_list, struct virtio_pmem_request, list); - req_buf->wq_buf_avail = true; + list_del_init(&req_buf->list); + WRITE_ONCE(req_buf->wq_buf_avail, true); wake_up(&req_buf->wq_buf); - list_del(&req_buf->list); } /* The interrupt handler */ @@ -40,7 +40,7 @@ void virtio_pmem_host_ack(struct virtqueue *vq) 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; + WRITE_ONCE(req_data->done, true); wake_up(&req_data->host_acked); } spin_unlock_irqrestore(&vpmem->pmem_lock, flags); @@ -72,7 +72,7 @@ static int virtio_pmem_flush(struct nd_region *nd_region) if (!req_data) return -ENOMEM; - req_data->done = false; + WRITE_ONCE(req_data->done, false); init_waitqueue_head(&req_data->host_acked); init_waitqueue_head(&req_data->wq_buf); INIT_LIST_HEAD(&req_data->list); @@ -93,12 +93,12 @@ static int virtio_pmem_flush(struct nd_region *nd_region) GFP_ATOMIC)) == -ENOSPC) { dev_info(&vdev->dev, "failed to send command to virtio pmem device, no free slots in the virtqueue\n"); - req_data->wq_buf_avail = false; + WRITE_ONCE(req_data->wq_buf_avail, false); list_add_tail(&req_data->list, &vpmem->req_list); spin_unlock_irqrestore(&vpmem->pmem_lock, flags); /* A host response results in "host_ack" getting called */ - wait_event(req_data->wq_buf, req_data->wq_buf_avail); + wait_event(req_data->wq_buf, READ_ONCE(req_data->wq_buf_avail)); spin_lock_irqsave(&vpmem->pmem_lock, flags); } err1 = virtqueue_kick(vpmem->req_vq); @@ -112,7 +112,7 @@ static int virtio_pmem_flush(struct nd_region *nd_region) err = -EIO; } else { /* A host response results in "host_ack" getting called */ - wait_event(req_data->host_acked, req_data->done); + wait_event(req_data->host_acked, READ_ONCE(req_data->done)); err = le32_to_cpu(req_data->resp.ret); } -- 2.53.0