diff options
| 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_fd.c | |
| parent | 38dbfb59d1175ef458d006556061adeaa8751b72 (diff) | |
| download | linux-2b6e72ed747f68a038df616efd86744b3644d694.tar.bz2 | |
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_fd.c')
| -rw-r--r-- | net/9p/trans_fd.c | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index b7bd7f2961bf..193efd562466 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -212,15 +212,9 @@ static void p9_conn_cancel(struct p9_conn *m, int err) m->err = err; list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) { - req->status = REQ_STATUS_ERROR; - if (!req->t_err) - req->t_err = err; list_move(&req->req_list, &cancel_list); } list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) { - req->status = REQ_STATUS_ERROR; - if (!req->t_err) - req->t_err = err; list_move(&req->req_list, &cancel_list); } spin_unlock_irqrestore(&m->client->lock, flags); @@ -228,7 +222,9 @@ static void p9_conn_cancel(struct p9_conn *m, int err) list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) { p9_debug(P9_DEBUG_ERROR, "call back req %p\n", req); list_del(&req->req_list); - p9_client_cb(m->client, req); + if (!req->t_err) + req->t_err = err; + p9_client_cb(m->client, req, REQ_STATUS_ERROR); } } @@ -302,6 +298,7 @@ static void p9_read_work(struct work_struct *work) { int n, err; struct p9_conn *m; + int status = REQ_STATUS_ERROR; m = container_of(work, struct p9_conn, rq); @@ -375,10 +372,10 @@ static void p9_read_work(struct work_struct *work) p9_debug(P9_DEBUG_TRANS, "got new packet\n"); spin_lock(&m->client->lock); if (m->req->status != REQ_STATUS_ERROR) - m->req->status = REQ_STATUS_RCVD; + status = REQ_STATUS_RCVD; list_del(&m->req->req_list); spin_unlock(&m->client->lock); - p9_client_cb(m->client, m->req); + p9_client_cb(m->client, m->req, status); m->rbuf = NULL; m->rpos = 0; m->rsize = 0; |