9p: eliminate callback complexity
The current trans_fd rpc mechanisms use a dynamic callback mechanism which
introduces a lot of complexity which only accomodates a single special case.
This patch removes much of that complexity in favor of a simple exception
mechanism to deal with flushes.
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index dbb057d..180163b 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -105,9 +105,6 @@
Flushed,
};
-struct p9_req;
-typedef void (*p9_conn_req_callback)(struct p9_req *req, void *a);
-
/**
* struct p9_req - fd mux encoding of an rpc transaction
* @lock: protects req_list
@@ -115,8 +112,6 @@
* @tcall: request &p9_fcall structure
* @rcall: response &p9_fcall structure
* @err: error state
- * @cb: callback for when response is received
- * @cba: argument to pass to callback
* @flush: flag to indicate RPC has been flushed
* @req_list: list link for higher level objects to chain requests
* @m: connection this request was issued on
@@ -130,8 +125,6 @@
struct p9_fcall *tcall;
struct p9_fcall *rcall;
int err;
- p9_conn_req_callback cb;
- void *cba;
int flush;
struct list_head req_list;
struct p9_conn *m;
@@ -231,6 +224,65 @@
spin_unlock_irqrestore(&p9_poll_lock, flags);
}
+static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)
+{
+ p9_mux_put_tag(m, req->tag);
+ kfree(req);
+}
+
+static void p9_conn_rpc_cb(struct p9_req *req);
+
+static void p9_mux_flush_cb(struct p9_req *freq)
+{
+ int tag;
+ struct p9_conn *m = freq->m;
+ struct p9_req *req, *rreq, *rptr;
+
+ P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
+ freq->tcall, freq->rcall, freq->err,
+ freq->tcall->params.tflush.oldtag);
+
+ spin_lock(&m->lock);
+ tag = freq->tcall->params.tflush.oldtag;
+ req = NULL;
+ list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
+ if (rreq->tag == tag) {
+ req = rreq;
+ list_del(&req->req_list);
+ break;
+ }
+ }
+ spin_unlock(&m->lock);
+
+ if (req) {
+ spin_lock(&req->lock);
+ req->flush = Flushed;
+ spin_unlock(&req->lock);
+
+ p9_conn_rpc_cb(req);
+ }
+
+ kfree(freq->tcall);
+ kfree(freq->rcall);
+ p9_mux_free_request(m, freq);
+}
+
+static void p9_conn_rpc_cb(struct p9_req *req)
+{
+ P9_DPRINTK(P9_DEBUG_MUX, "req %p\n", req);
+
+ if (req->tcall->id == P9_TFLUSH) { /* flush callback */
+ P9_DPRINTK(P9_DEBUG_MUX, "flush req %p\n", req);
+ p9_mux_flush_cb(req);
+ } else { /* normal wakeup path */
+ P9_DPRINTK(P9_DEBUG_MUX, "normal req %p\n", req);
+ if (req->flush != None && !req->err)
+ req->err = -ERESTARTSYS;
+
+ wake_up(&req->wqueue);
+ }
+}
+
/**
* p9_conn_cancel - cancel all pending requests with error
* @m: mux data
@@ -259,10 +311,7 @@
if (!req->err)
req->err = err;
- if (req->cb)
- (*req->cb) (req, req->cba);
- else
- kfree(req->rcall);
+ p9_conn_rpc_cb(req);
}
}
@@ -472,12 +521,8 @@
req->rcall = rcall;
process_request(m, req);
- if (req->flush != Flushing) {
- if (req->cb)
- (*req->cb) (req, req->cba);
- else
- kfree(req->rcall);
- }
+ if (req->flush != Flushing)
+ p9_conn_rpc_cb(req);
} else {
if (err >= 0 && rcall->id != P9_RFLUSH)
P9_DPRINTK(P9_DEBUG_ERROR,
@@ -786,14 +831,10 @@
*
* @m: mux data
* @tc: request to be sent
- * @cb: callback function to call when response is received
- * @cba: parameter to pass to the callback function
*
*/
-static struct p9_req *p9_send_request(struct p9_conn *m,
- struct p9_fcall *tc,
- p9_conn_req_callback cb, void *cba)
+static struct p9_req *p9_send_request(struct p9_conn *m, struct p9_fcall *tc)
{
int n;
struct p9_req *req;
@@ -835,8 +876,6 @@
req->tcall = tc;
req->rcall = NULL;
req->err = 0;
- req->cb = cb;
- req->cba = cba;
req->flush = None;
spin_lock(&m->lock);
@@ -854,51 +893,6 @@
return req;
}
-static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)
-{
- p9_mux_put_tag(m, req->tag);
- kfree(req);
-}
-
-static void p9_mux_flush_cb(struct p9_req *freq, void *a)
-{
- int tag;
- struct p9_conn *m;
- struct p9_req *req, *rreq, *rptr;
-
- m = a;
- P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
- freq->tcall, freq->rcall, freq->err,
- freq->tcall->params.tflush.oldtag);
-
- spin_lock(&m->lock);
- tag = freq->tcall->params.tflush.oldtag;
- req = NULL;
- list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
- if (rreq->tag == tag) {
- req = rreq;
- list_del(&req->req_list);
- break;
- }
- }
- spin_unlock(&m->lock);
-
- if (req) {
- spin_lock(&req->lock);
- req->flush = Flushed;
- spin_unlock(&req->lock);
-
- if (req->cb)
- (*req->cb) (req, req->cba);
- else
- kfree(req->rcall);
- }
-
- kfree(freq->tcall);
- kfree(freq->rcall);
- p9_mux_free_request(m, freq);
-}
-
static int
p9_mux_flush_request(struct p9_conn *m, struct p9_req *req)
{
@@ -928,8 +922,7 @@
list_del(&rreq->req_list);
req->flush = Flushed;
spin_unlock(&m->lock);
- if (req->cb)
- (*req->cb) (req, req->cba);
+ p9_conn_rpc_cb(req);
return 0;
}
}
@@ -937,20 +930,10 @@
clear_thread_flag(TIF_SIGPENDING);
fc = p9_create_tflush(req->tag);
- p9_send_request(m, fc, p9_mux_flush_cb, m);
+ p9_send_request(m, fc);
return 1;
}
-static void p9_conn_rpc_cb(struct p9_req *req, void *a)
-{
- P9_DPRINTK(P9_DEBUG_MUX, "req %p arg %p\n", req, a);
-
- if (req->flush != None && !req->err)
- req->err = -ERESTARTSYS;
-
- wake_up(&req->wqueue);
-}
-
/**
* p9_fd_rpc- sends 9P request and waits until a response is available.
* The function can be interrupted.
@@ -978,7 +961,7 @@
clear_thread_flag(TIF_SIGPENDING);
}
- req = p9_send_request(m, tc, p9_conn_rpc_cb, NULL);
+ req = p9_send_request(m, tc);
if (IS_ERR(req)) {
err = PTR_ERR(req);
P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);