From: Sasha Levin <sashal@kernel.org>
To: stable@vger.kernel.org
Cc: Li Chen <me@linux.beauty>,
Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Sasha Levin <sashal@kernel.org>
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 [thread overview]
Message-ID: <20260911003410.3483414-5-sashal@kernel.org> (raw)
In-Reply-To: <20260911003410.3483414-1-sashal@kernel.org>
From: Li Chen <me@linux.beauty>
[ 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 <pankaj.gupta.linux@gmail.com>
Signed-off-by: Li Chen <me@linux.beauty>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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 <sashal@kernel.org>
---
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
next prev parent reply other threads:[~2026-09-11 0:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-09 9:51 FAILED: patch "[PATCH] nvdimm: virtio_pmem: refcount requests for token lifetime" failed to apply to 6.18-stable tree gregkh
2026-09-11 0:34 ` [PATCH 6.18.y 1/6] nvdimm: preserve flush callback -ENOMEM Sasha Levin
2026-09-11 0:34 ` [PATCH 6.18.y 2/6] nvdimm: pmem: keep PREFLUSH before data writes Sasha Levin
2026-09-11 0:34 ` [PATCH 6.18.y 3/6] nvdimm: virtio_pmem: stop allocating child flush bio Sasha Levin
2026-09-11 0:34 ` [PATCH 6.18.y 4/6] nvdimm: virtio_pmem: always wake -ENOSPC waiters Sasha Levin
2026-09-11 0:34 ` Sasha Levin [this message]
2026-09-11 0:34 ` [PATCH 6.18.y 6/6] nvdimm: virtio_pmem: refcount requests for token lifetime Sasha Levin
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