From: J. Bruce Fields <bfields@redhat.com>
Date: Mon, 13 Feb 2012 21:13:41 +0000 (-0500)
Subject: nfsd4: fix sessions slotid wraparound logic
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=f6d82485e9a947ae19bb29e72644f4c6f27d5b89;p=deliverable%2Flinux.git

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>
---

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;
 }