FAILED: patch "[PATCH] NFS: Avoid RCU usage in tracepoints" failed to apply to 3.18-stable tree

FAILED: patch "[PATCH] NFS: Avoid RCU usage in tracepoints" failed to apply to 3.18-stable tree

[gregkh]

The patch below does not apply to the 3.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 3944369db701f075092357b511fd9f5755771585 Mon Sep 17 00:00:00 2001
From: Anna Schumaker <Anna.Schumaker@Netapp.com>
Date: Wed, 1 Nov 2017 15:48:43 -0400
Subject: [PATCH] NFS: Avoid RCU usage in tracepoints

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>
Cc: stable@vger.kernel.org # v3.12
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h
index be1da19c65d6..7a5588c25f70 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(
@@ -1132,9 +1128,7 @@ 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(
@@ -1147,9 +1141,7 @@ 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(
@@ -1191,9 +1183,7 @@ 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)
 		),
@@ -1208,9 +1198,7 @@ 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 =