Merge tag 'nfs-for-3.20-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull more NFS client updates from Trond Myklebust:
 "Highlights include:

   - Fix a use-after-free in decode_cb_sequence_args()
   - Fix a compile error when #undef CONFIG_PROC_FS
   - NFSv4.1 backchannel spinlocking issue
   - Cleanups in the NFS unstable write code requested by Linus
   - NFSv4.1 fix issues when the server denies our backchannel request
   - Cleanups in create_session and bind_conn_to_session"

* tag 'nfs-for-3.20-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFSv4.1: Clean up bind_conn_to_session
  NFSv4.1: Always set up a forward channel when binding the session
  NFSv4.1: Don't set up a backchannel if the server didn't agree to do so
  NFSv4.1: Clean up create_session
  pnfs: Refactor the *_layout_mark_request_commit to use pnfs_layout_mark_request_commit
  NFSv4: Kill unused nfs_inode->delegation_state field
  NFS: struct nfs_commit_info.lock must always point to inode->i_lock
  nfs: Can call nfs_clear_page_commit() instead
  nfs: Provide and use helper functions for marking a page as unstable
  SUNRPC: Always manipulate rpc_rqst::rq_bc_pa_list under xprt->bc_pa_lock
  SUNRPC: Fix a compile error when #undef CONFIG_PROC_FS
  NFSv4.1: Convert open-coded array allocation calls to kmalloc_array()
  NFSv4.1: Fix a kfree() of uninitialised pointers in decode_cb_sequence_args

1 files changed, 4 insertions, 1 deletions

diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 651f49ab601f..9dd0ea8db463 100644
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -309,12 +309,15 @@ void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
         struct rpc_xprt *xprt = req->rq_xprt;
         struct svc_serv *bc_serv = xprt->bc_serv;
 
+        spin_lock(&xprt->bc_pa_lock);
+        list_del(&req->rq_bc_pa_list);
+        spin_unlock(&xprt->bc_pa_lock);
+
         req->rq_private_buf.len = copied;
         set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
 
         dprintk("RPC:       add callback request to list\n");
         spin_lock(&bc_serv->sv_cb_lock);
-        list_del(&req->rq_bc_pa_list);
         list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
         wake_up(&bc_serv->sv_cb_waitq);
         spin_unlock(&bc_serv->sv_cb_lock);