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nfs: fix RCU cl_xprt handling in nfs_swap_activate/deactivate

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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] <asn:4>*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] <asn:4>*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 <mgorman@suse.de>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
Jeff Layton 2014-09-10 09:03:55 -04:00 committed by Trond Myklebust
parent 08a899d5d9
commit dad2b015bb
1 changed files with 14 additions and 2 deletions
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16
fs/nfs/file.c
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@ -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