[PATCH 2.5.60] Clean up and fix SMP issue w.r.t. XID allocation

From: Trond Myklebust (trond.myklebust@fys.uio.no)
Date: Thu Feb 13 2003 - 09:52:50 EST


The following problem was identified by Olaf Kirch. In
xprt_request_init(), the XID allocation needs to be protected by a
global spinlock.

Cheers,
  Trond

diff -u --recursive --new-file linux-2.5.60-00-fix_pipes/net/sunrpc/xprt.c linux-2.5.60-01-fix_xid/net/sunrpc/xprt.c
--- linux-2.5.60-00-fix_pipes/net/sunrpc/xprt.c 2003-01-12 22:39:48.000000000 +0100
+++ linux-2.5.60-01-fix_xid/net/sunrpc/xprt.c 2003-02-13 14:17:10.000000000 +0100
@@ -1273,25 +1273,41 @@
 }
 
 /*
+ * Allocate a 'unique' XID
+ */
+static u32
+xprt_alloc_xid(void)
+{
+ static spinlock_t xid_lock = SPIN_LOCK_UNLOCKED;
+ static int need_init = 1;
+ static u32 xid;
+ u32 ret;
+
+ spin_lock(&xid_lock);
+ if (unlikely(need_init)) {
+ xid = get_seconds() << 12;
+ need_init = 0;
+ }
+ ret = xid++;
+ spin_unlock(&xid_lock);
+ return ret;
+}
+
+/*
  * Initialize RPC request
  */
 static void
 xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
 {
         struct rpc_rqst *req = task->tk_rqstp;
- static u32 xid = 0;
-
- if (!xid)
- xid = get_seconds() << 12;
 
- dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid, req, xid);
         req->rq_timeout = xprt->timeout;
         req->rq_task = task;
         req->rq_xprt = xprt;
- req->rq_xid = xid++;
- if (!xid)
- xid++;
+ req->rq_xid = xprt_alloc_xid();
         INIT_LIST_HEAD(&req->rq_list);
+ dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
+ req, req->rq_xid);
 }
 
 /*
-
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