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authorDominique Martinet <dominique.martinet@cea.fr>2014-01-17 21:31:00 +0400
committerEric Van Hensbergen <ericvh@gmail.com>2014-03-26 01:37:59 +0400
commit2b6e72ed747f68a038df616efd86744b3644d694 (patch)
treed781427484432608a74ccc44fd4a7a3296751f23 /net/9p/trans_virtio.c
parent38dbfb59d1175ef458d006556061adeaa8751b72 (diff)
downloadlinux-2b6e72ed747f68a038df616efd86744b3644d694.tar.xz
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.c3
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);
}
}