nfsd4: fix sessions slotid wraparound logic

From RFC 5661 2.10.6.1: "If the previous sequence ID was 0xFFFFFFFF,
then the next request for the slot MUST have the sequence ID set to
zero."

While we're there, delete some redundant comments.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index e8c98f009670..2095dbb2923e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1575,16 +1575,11 @@ check_slot_seqid(u32 seqid, u32 slot_seqid, int slot_inuse)
                 else
                         return nfserr_seq_misordered;
         }
-        /* Normal */
+        /* Note unsigned 32-bit arithmetic handles wraparound: */
         if (likely(seqid == slot_seqid + 1))
                 return nfs_ok;
-        /* Replay */
         if (seqid == slot_seqid)
                 return nfserr_replay_cache;
-        /* Wraparound */
-        if (seqid == 1 && (slot_seqid + 1) == 0)
-                return nfs_ok;
-        /* Misordered replay or misordered new request */
         return nfserr_seq_misordered;
 }