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| author |   Dominique Martinet <dominique.martinet@cea.fr> | 2014-01-17 18:31:00 +0100 |
|---|---|---|
| committer |   Eric Van Hensbergen <ericvh@gmail.com> | 2014-03-25 16:37:59 -0500 |
| commit | 2b6e72ed747f68a038df616efd86744b3644d694 (patch) | |
| tree | d781427484432608a74ccc44fd4a7a3296751f23 /net/9p/trans_virtio.c | |
| parent | Linus 3.14-rc1 (diff) | |
| download | linux-dev-2b6e72ed747f68a038df616efd86744b3644d694.tar.xz linux-dev-2b6e72ed747f68a038df616efd86744b3644d694.zip | |
9P: Add memory barriers to protect request fields over cb/rpc threads handoff
We need barriers to guarantee this pattern works as intended:
[w] req->rc, 1 [r] req->status, 1
wmb rmb
[w] req->status, 1 [r] req->rc
Where the wmb ensures that rc gets written before status,
and the rmb ensures that if you observe status == 1, rc is the new value.
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Diffstat (limited to 'net/9p/trans_virtio.c')
| -rw-r--r-- | net/9p/trans_virtio.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index cd1e1ede73a4..a8c67e2be3f8 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -164,8 +164,7 @@ static void req_done(struct virtqueue *vq) p9_debug(P9_DEBUG_TRANS, ": rc %p\n", rc); p9_debug(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag); req = p9_tag_lookup(chan->client, rc->tag); - req->status = REQ_STATUS_RCVD; - p9_client_cb(chan->client, req); + p9_client_cb(chan->client, req, REQ_STATUS_RCVD); } } |