nfsd: allow nfsd_file_get to sanely handle a NULL pointer

...and remove some now-useless NULL pointer checks in its callers.

Suggested-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index c0950edb26b0d31ca9c5b9bcceaf9166b9cb2c2f..ecc32105c3abfe2b202295fd83d2a0cd87519abb 100644 (file)
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -452,7 +452,7 @@ static bool nfsd_file_lru_remove(struct nfsd_file *nf)
 struct nfsd_file *
 nfsd_file_get(struct nfsd_file *nf)
 {
-       if (likely(refcount_inc_not_zero(&nf->nf_ref)))
+       if (nf && refcount_inc_not_zero(&nf->nf_ref))
                return nf;
        return NULL;
 }
@@ -1107,8 +1107,7 @@ retry:
        rcu_read_lock();
        nf = rhashtable_lookup(&nfsd_file_rhash_tbl, &key,
                               nfsd_file_rhash_params);
-       if (nf)
-               nf = nfsd_file_get(nf);
+       nf = nfsd_file_get(nf);
        rcu_read_unlock();
 
        if (nf) {

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index c69f27d3adb79469eb8e7a0cda623d8816eb1224..9657dab980cb55018371be2a36cbcf1051f37d0b 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -602,9 +602,7 @@ put_nfs4_file(struct nfs4_file *fi)
 static struct nfsd_file *
 __nfs4_get_fd(struct nfs4_file *f, int oflag)
 {
-       if (f->fi_fds[oflag])
-               return nfsd_file_get(f->fi_fds[oflag]);
-       return NULL;
+       return nfsd_file_get(f->fi_fds[oflag]);
 }
 
 static struct nfsd_file *