From dad2b015bb85799f8005da637954f8eafb83f34c Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Wed, 10 Sep 2014 09:03:55 -0400 Subject: [PATCH] nfs: fix RCU cl_xprt handling in nfs_swap_activate/deactivate sparse says: fs/nfs/file.c:543:60: warning: incorrect type in argument 1 (different address spaces) fs/nfs/file.c:543:60: expected struct rpc_xprt *xprt fs/nfs/file.c:543:60: got struct rpc_xprt [noderef] *cl_xprt fs/nfs/file.c:548:53: warning: incorrect type in argument 1 (different address spaces) fs/nfs/file.c:548:53: expected struct rpc_xprt *xprt fs/nfs/file.c:548:53: got struct rpc_xprt [noderef] *cl_xprt cl_xprt is RCU-managed, so we need to take care to dereference and use it while holding the RCU read lock. Cc: Mel Gorman Signed-off-by: Jeff Layton Signed-off-by: Trond Myklebust --- fs/nfs/file.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 05ef7dcc5f21..23e5f0ea5c83 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -546,13 +546,25 @@ static int nfs_launder_page(struct page *page) static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file, sector_t *span) { + int ret; + struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host); + *span = sis->pages; - return xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 1); + + rcu_read_lock(); + ret = xs_swapper(rcu_dereference(clnt->cl_xprt), 1); + rcu_read_unlock(); + + return ret; } static void nfs_swap_deactivate(struct file *file) { - xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 0); + struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host); + + rcu_read_lock(); + xs_swapper(rcu_dereference(clnt->cl_xprt), 0); + rcu_read_unlock(); } #endif