From: Anna Schumaker <Anna.Schumaker@Netapp.com>
Date: Wed, 1 Nov 2017 19:48:43 +0000 (-0400)
Subject: NFS: Avoid RCU usage in tracepoints
X-Git-Tag: archive/raspbian/4.9.80-2+rpi1~7^2~1174
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/%22mailto:kde%40ewsoftware.de//%22style.css/%22/%22http:/www.example.com/%22mailto:kde%40ewsoftware.de/%22style.css/%22?a=commitdiff_plain;h=8fb42f722743c226d1079e40d4ad96d8d8aef273;p=linux-4.9.git

NFS: Avoid RCU usage in tracepoints

commit 3944369db701f075092357b511fd9f5755771585 upstream.

There isn't an obvious way to acquire and release the RCU lock during a
tracepoint, so we can't use the rpc_peeraddr2str() function here.
Instead, rely on the client's cl_hostname, which should have similar
enough information without needing an rcu_dereference().

Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h
index cfb8f7ce5cf6..20cd8500452a 100644
--- a/fs/nfs/nfs4trace.h
+++ b/fs/nfs/nfs4trace.h
@@ -201,17 +201,13 @@ DECLARE_EVENT_CLASS(nfs4_clientid_event,
 		TP_ARGS(clp, error),
 
 		TP_STRUCT__entry(
-			__string(dstaddr,
-				rpc_peeraddr2str(clp->cl_rpcclient,
-					RPC_DISPLAY_ADDR))
+			__string(dstaddr, clp->cl_hostname)
 			__field(int, error)
 		),
 
 		TP_fast_assign(
 			__entry->error = error;
-			__assign_str(dstaddr,
-				rpc_peeraddr2str(clp->cl_rpcclient,
-						RPC_DISPLAY_ADDR));
+			__assign_str(dstaddr, clp->cl_hostname);
 		),
 
 		TP_printk(
@@ -1103,9 +1099,7 @@ DECLARE_EVENT_CLASS(nfs4_inode_callback_event,
 			__field(dev_t, dev)
 			__field(u32, fhandle)
 			__field(u64, fileid)
-			__string(dstaddr, clp ?
-				rpc_peeraddr2str(clp->cl_rpcclient,
-					RPC_DISPLAY_ADDR) : "unknown")
+			__string(dstaddr, clp ? clp->cl_hostname : "unknown")
 		),
 
 		TP_fast_assign(
@@ -1118,9 +1112,7 @@ DECLARE_EVENT_CLASS(nfs4_inode_callback_event,
 				__entry->fileid = 0;
 				__entry->dev = 0;
 			}
-			__assign_str(dstaddr, clp ?
-				rpc_peeraddr2str(clp->cl_rpcclient,
-					RPC_DISPLAY_ADDR) : "unknown")
+			__assign_str(dstaddr, clp ? clp->cl_hostname : "unknown")
 		),
 
 		TP_printk(
@@ -1162,9 +1154,7 @@ DECLARE_EVENT_CLASS(nfs4_inode_stateid_callback_event,
 			__field(dev_t, dev)
 			__field(u32, fhandle)
 			__field(u64, fileid)
-			__string(dstaddr, clp ?
-				rpc_peeraddr2str(clp->cl_rpcclient,
-					RPC_DISPLAY_ADDR) : "unknown")
+			__string(dstaddr, clp ? clp->cl_hostname : "unknown")
 			__field(int, stateid_seq)
 			__field(u32, stateid_hash)
 		),
@@ -1179,9 +1169,7 @@ DECLARE_EVENT_CLASS(nfs4_inode_stateid_callback_event,
 				__entry->fileid = 0;
 				__entry->dev = 0;
 			}
-			__assign_str(dstaddr, clp ?
-				rpc_peeraddr2str(clp->cl_rpcclient,
-					RPC_DISPLAY_ADDR) : "unknown")
+			__assign_str(dstaddr, clp ? clp->cl_hostname : "unknown")
 			__entry->stateid_seq =
 				be32_to_cpu(stateid->seqid);
 			__entry->stateid_hash =