+static void
+gen_sessionid(struct nfsd4_session *ses)
+{
+ struct nfs4_client *clp = ses->se_client;
+ struct nfsd4_sessionid *sid;
+
+ sid = (struct nfsd4_sessionid *)ses->se_sessionid.data;
+ sid->clientid = clp->cl_clientid;
+ sid->sequence = current_sessionid++;
+ sid->reserved = 0;
+}
+
+/*
+ * Give the client the number of slots it requests bound by
+ * NFSD_MAX_SLOTS_PER_SESSION and by sv_drc_max_pages.
+ *
+ * If we run out of pages (sv_drc_pages_used == sv_drc_max_pages) we
+ * should (up to a point) re-negotiate active sessions and reduce their
+ * slot usage to make rooom for new connections. For now we just fail the
+ * create session.
+ */
+static int set_forechannel_maxreqs(struct nfsd4_channel_attrs *fchan)
+{
+ int status = 0, np = fchan->maxreqs * NFSD_PAGES_PER_SLOT;
+
+ spin_lock(&nfsd_serv->sv_lock);
+ if (np + nfsd_serv->sv_drc_pages_used > nfsd_serv->sv_drc_max_pages)
+ np = nfsd_serv->sv_drc_max_pages - nfsd_serv->sv_drc_pages_used;
+ nfsd_serv->sv_drc_pages_used += np;
+ spin_unlock(&nfsd_serv->sv_lock);
+
+ if (np <= 0) {
+ status = nfserr_resource;
+ fchan->maxreqs = 0;
+ } else
+ fchan->maxreqs = np / NFSD_PAGES_PER_SLOT;
+
+ return status;
+}
+
+/*
+ * fchan holds the client values on input, and the server values on output
+ */
+static int init_forechannel_attrs(struct svc_rqst *rqstp,
+ struct nfsd4_session *session,
+ struct nfsd4_channel_attrs *fchan)
+{
+ int status = 0;
+ __u32 maxcount = svc_max_payload(rqstp);
+
+ /* headerpadsz set to zero in encode routine */
+
+ /* Use the client's max request and max response size if possible */
+ if (fchan->maxreq_sz > maxcount)
+ fchan->maxreq_sz = maxcount;
+ session->se_fmaxreq_sz = fchan->maxreq_sz;
+
+ if (fchan->maxresp_sz > maxcount)
+ fchan->maxresp_sz = maxcount;
+ session->se_fmaxresp_sz = fchan->maxresp_sz;
+
+ /* Set the max response cached size our default which is
+ * a multiple of PAGE_SIZE and small */
+ session->se_fmaxresp_cached = NFSD_PAGES_PER_SLOT * PAGE_SIZE;
+ fchan->maxresp_cached = session->se_fmaxresp_cached;
+
+ /* Use the client's maxops if possible */
+ if (fchan->maxops > NFSD_MAX_OPS_PER_COMPOUND)
+ fchan->maxops = NFSD_MAX_OPS_PER_COMPOUND;
+ session->se_fmaxops = fchan->maxops;
+
+ /* try to use the client requested number of slots */
+ if (fchan->maxreqs > NFSD_MAX_SLOTS_PER_SESSION)
+ fchan->maxreqs = NFSD_MAX_SLOTS_PER_SESSION;
+
+ /* FIXME: Error means no more DRC pages so the server should
+ * recover pages from existing sessions. For now fail session
+ * creation.
+ */
+ status = set_forechannel_maxreqs(fchan);
+
+ session->se_fnumslots = fchan->maxreqs;
+ return status;
+}
+
+static int
+alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client *clp,
+ struct nfsd4_create_session *cses)
+{
+ struct nfsd4_session *new, tmp;
+ int idx, status = nfserr_resource, slotsize;
+
+ memset(&tmp, 0, sizeof(tmp));
+
+ /* FIXME: For now, we just accept the client back channel attributes. */
+ status = init_forechannel_attrs(rqstp, &tmp, &cses->fore_channel);
+ if (status)
+ goto out;
+
+ /* allocate struct nfsd4_session and slot table in one piece */
+ slotsize = tmp.se_fnumslots * sizeof(struct nfsd4_slot);
+ new = kzalloc(sizeof(*new) + slotsize, GFP_KERNEL);
+ if (!new)
+ goto out;
+
+ memcpy(new, &tmp, sizeof(*new));
+
+ new->se_client = clp;
+ gen_sessionid(new);
+ idx = hash_sessionid(&new->se_sessionid);
+ memcpy(clp->cl_sessionid.data, new->se_sessionid.data,
+ NFS4_MAX_SESSIONID_LEN);
+
+ new->se_flags = cses->flags;
+ kref_init(&new->se_ref);
+ spin_lock(&sessionid_lock);
+ list_add(&new->se_hash, &sessionid_hashtbl[idx]);
+ list_add(&new->se_perclnt, &clp->cl_sessions);
+ spin_unlock(&sessionid_lock);
+
+ status = nfs_ok;
+out:
+ return status;
+}
+