NFSv4: Fixup smatch warning for ambiguous return

Dan Carpenter reports smatch warning for nfs4_try_migration() when a memory
allocation failure results in a zero return value.  In this case, a
transient allocation failure error will likely be retried the next time the
server responds with NFS4ERR_MOVED.

We can fixup the smatch warning with a small refactor: attempt all three
allocations before testing and returning on a failure.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: c3ed222745d9 ("NFSv4: Fix free of uninitialized nfs4_label on referral lookup.")
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 662e86ea3a2ddadb7331f9e122c537ca075830e9..5b452411e8fdf23e055aec9907bae86b82d4702b 100644 (file)
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -2116,6 +2116,7 @@ static int nfs4_try_migration(struct nfs_server *server, const struct cred *cred
 {
        struct nfs_client *clp = server->nfs_client;
        struct nfs4_fs_locations *locations = NULL;
+       struct nfs_fattr *fattr;
        struct inode *inode;
        struct page *page;
        int status, result;
@@ -2125,19 +2126,16 @@ static int nfs4_try_migration(struct nfs_server *server, const struct cred *cred
                        (unsigned long long)server->fsid.minor,
                        clp->cl_hostname);
 
-       result = 0;
        page = alloc_page(GFP_KERNEL);
        locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
-       if (page == NULL || locations == NULL) {
-               dprintk("<-- %s: no memory\n", __func__);
-               goto out;
-       }
-       locations->fattr = nfs_alloc_fattr();
-       if (locations->fattr == NULL) {
+       fattr = nfs_alloc_fattr();
+       if (page == NULL || locations == NULL || fattr == NULL) {
                dprintk("<-- %s: no memory\n", __func__);
+               result = 0;
                goto out;
        }
 
+       locations->fattr = fattr;
        inode = d_inode(server->super->s_root);
        result = nfs4_proc_get_locations(server, NFS_FH(inode), locations,
                                         page, cred);