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 A3D07380FC7 for ; Fri, 11 Sep 2026 01:44:00 +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=1789091043; cv=none; b=JaMuYjyClIvdHEVxp9J4NymZupYJAELa+pp4pRdKgqzgOf+d8uF9V/WJAWu2WueLWhiGA2BGspEJDwNFsjK84UhnruxdcokO2HkiG1SFJqfNEX8hXLKeNktbFCLK1YtTbY0Vs5h/9FPQcHSFdxSh/DnCOPOI0zargzY9zBEtzxw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789091043; c=relaxed/simple; bh=JCgCU67i5MmpmvYje9awvuCmPLvqeh4HVbP66BetM8c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E3vSSZ5yitk5qgvnGXQIcru/lj+Gxahvs6/wNVXmDs94yRb3LvrhtIXDMXPB3sUbxRnv5Xj/Q7rNGrnJPG7leD5pEJipvV9H1cOr50ms8jwngpWNp59obPWrflFmguY8h7LYAJ9FrErVwcY3AUN2unfXHBoefoWYQFfOoqYGWwQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=b2OGq4o7; 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="b2OGq4o7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E89011F0089C; Fri, 11 Sep 2026 01:43:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789091040; bh=/TtN6eHeLLTSS9JwR2G1HLAGCROTsxOMyHDVTpidaD8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=b2OGq4o7jIOWkvVjs+VtD6kf7Hn1zFH1Tw8hZh1EaSLm7ix0VWYd1RJeAQ1kayQVr p+EzeD2ZkiBVU8Vyh6jiV9uz2aSpu8grL6Py1ZttndnNQ4gy3yOSFmDYeoDZHS/Fjg Yn6TnopSoIl4yjDX9fgN3oE/jgXn2a0KWv8EtHftD2yHP8RdXe7BT91vdU3Awm0Opx yZRsLS2ah9VT2bX7A4D//CqnibqnALDzBse06romrk4+dJr0rahG3Em9WR2Hxe0V1Z HT6YeqfH0Beoo7JJuLdDhdIqv3gTYib20qbhFJtBq3RC8ExKB+fw/5Z+BC+3Bn0/6Y bjNeZLpLhIfvQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Li Chen , Pankaj Gupta , "Michael S. Tsirkin" , Sasha Levin Subject: [PATCH 6.6.y 5/6] nvdimm: virtio_pmem: use READ_ONCE()/WRITE_ONCE() for wait flags Date: Thu, 10 Sep 2026 21:43:54 -0400 Message-ID: <20260911014355.4149601-5-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260911014355.4149601-1-sashal@kernel.org> References: <2026090939-disdain-corridor-626c@gregkh> <20260911014355.4149601-1-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 4b81544db4a61..ce3f14d99eac6 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