[bug report] NFSv4: Observe the NFS_MOUNT_SOFTREVAL flag in _nfs4_proc_lookupp

[Dan Carpenter <dan.carpenter@linaro.org>]

Hello Trond Myklebust,

This is a new checker rule Harshit and I wrote.

Commit 76998ebb9158 ("NFSv4: Observe the NFS_MOUNT_SOFTREVAL flag in
_nfs4_proc_lookupp") from Oct 20, 2020 (linux-next), leads to the
following Smatch static checker warning:

	fs/nfs/nfs4proc.c:783 nfs4_init_sequence()
	warn: potentially more than 1 'args->sa_cache_this = 0x1001' type='uchar'

fs/nfs/nfs4proc.c
    778 void nfs4_init_sequence(struct nfs4_sequence_args *args,
    779                         struct nfs4_sequence_res *res, int cache_reply,
    780                         int privileged)
    781 {
    782         args->sa_slot = NULL;
--> 783         args->sa_cache_this = cache_reply;

args->sa_cache_this is a 1 bit bitfield in a u8, but the commit mentioned
is passing RPC_TASK_TIMEOUT (0x1000).  Should this code be changed to:

	args->sa_cache_this = cache_reply & RPC_TASK_ASYNC;

Probably not...  _nfs4_proc_lookupp() is the only caller which passes
anything other than zero.

    784         args->sa_privileged = privileged;
    785 
    786         res->sr_slot = NULL;
    787 }

regards,
dan carpenter