NFSv4.1: Convert slotid from u8 to u32

It is perfectly legal to negotiate up to 2^32-1 slots in the protocol,
and with 10GigE, we are already seeing that 255 slots is far too limiting.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/callback.h

@@ -38,7 +38,7 @@ enum nfs4_callback_opnum {
 struct cb_process_state {
 	__be32			drc_status;
 	struct nfs_client	*clp;
-	int			slotid;
+	u32			slotid;
 	struct net		*net;
 };
 

fs/nfs/callback_xdr.c

@@ -759,14 +759,14 @@ static void nfs4_callback_free_slot(struct nfs4_session *session)
 	 * Let the state manager know callback processing done.
 	 * A single slot, so highest used slotid is either 0 or -1
 	 */
-	tbl->highest_used_slotid = -1;
+	tbl->highest_used_slotid = NFS4_NO_SLOT;
 	nfs4_check_drain_bc_complete(session);
 	spin_unlock(&tbl->slot_tbl_lock);
 }
 
 static void nfs4_cb_free_slot(struct cb_process_state *cps)
 {
-	if (cps->slotid != -1)
+	if (cps->slotid != NFS4_NO_SLOT)
 		nfs4_callback_free_slot(cps->clp->cl_session);
 }
 
@@ -860,7 +860,7 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *r
 	struct cb_process_state cps = {
 		.drc_status = 0,
 		.clp = NULL,
-		.slotid = -1,
+		.slotid = NFS4_NO_SLOT,
 		.net = rqstp->rq_xprt->xpt_net,
 	};
 	unsigned int nops = 0;

fs/nfs/nfs4proc.c

@@ -360,16 +360,14 @@ static void renew_lease(const struct nfs_server *server, unsigned long timestamp
  * When updating highest_used_slotid there may be "holes" in the bitmap
  * so we need to scan down from highest_used_slotid to 0 looking for the now
  * highest slotid in use.
- * If none found, highest_used_slotid is set to -1.
+ * If none found, highest_used_slotid is set to NFS4_NO_SLOT.
  *
  * Must be called while holding tbl->slot_tbl_lock
  */
 static void
-nfs4_free_slot(struct nfs4_slot_table *tbl, u8 free_slotid)
+nfs4_free_slot(struct nfs4_slot_table *tbl, u32 slotid)
 {
-	int slotid = free_slotid;
-
-	BUG_ON(slotid < 0 || slotid >= NFS4_MAX_SLOT_TABLE);
+	BUG_ON(slotid >= NFS4_MAX_SLOT_TABLE);
 	/* clear used bit in bitmap */
 	__clear_bit(slotid, tbl->used_slots);
 
@@ -379,10 +377,10 @@ nfs4_free_slot(struct nfs4_slot_table *tbl, u8 free_slotid)
 		if (slotid < tbl->max_slots)
 			tbl->highest_used_slotid = slotid;
 		else
-			tbl->highest_used_slotid = -1;
+			tbl->highest_used_slotid = NFS4_NO_SLOT;
 	}
-	dprintk("%s: free_slotid %u highest_used_slotid %d\n", __func__,
-		free_slotid, tbl->highest_used_slotid);
+	dprintk("%s: slotid %u highest_used_slotid %d\n", __func__,
+		slotid, tbl->highest_used_slotid);
 }
 
 bool nfs4_set_task_privileged(struct rpc_task *task, void *dummy)
@@ -402,7 +400,7 @@ static void nfs4_check_drain_fc_complete(struct nfs4_session *ses)
 		return;
 	}
 
-	if (ses->fc_slot_table.highest_used_slotid != -1)
+	if (ses->fc_slot_table.highest_used_slotid != NFS4_NO_SLOT)
 		return;
 
 	dprintk("%s COMPLETE: Session Fore Channel Drained\n", __func__);
@@ -415,7 +413,7 @@ static void nfs4_check_drain_fc_complete(struct nfs4_session *ses)
 void nfs4_check_drain_bc_complete(struct nfs4_session *ses)
 {
 	if (!test_bit(NFS4_SESSION_DRAINING, &ses->session_state) ||
-	    ses->bc_slot_table.highest_used_slotid != -1)
+	    ses->bc_slot_table.highest_used_slotid != NFS4_NO_SLOT)
 		return;
 	dprintk("%s COMPLETE: Session Back Channel Drained\n", __func__);
 	complete(&ses->bc_slot_table.complete);
@@ -510,25 +508,25 @@ static int nfs4_sequence_done(struct rpc_task *task,
  * nfs4_find_slot looks for an unset bit in the used_slots bitmap.
  * If found, we mark the slot as used, update the highest_used_slotid,
  * and respectively set up the sequence operation args.
- * The slot number is returned if found, or NFS4_MAX_SLOT_TABLE otherwise.
+ * The slot number is returned if found, or NFS4_NO_SLOT otherwise.
  *
  * Note: must be called with under the slot_tbl_lock.
  */
-static u8
+static u32
 nfs4_find_slot(struct nfs4_slot_table *tbl)
 {
-	int slotid;
-	u8 ret_id = NFS4_MAX_SLOT_TABLE;
-	BUILD_BUG_ON((u8)NFS4_MAX_SLOT_TABLE != (int)NFS4_MAX_SLOT_TABLE);
+	u32 slotid;
+	u32 ret_id = NFS4_NO_SLOT;
 
-	dprintk("--> %s used_slots=%04lx highest_used=%d max_slots=%d\n",
+	dprintk("--> %s used_slots=%04lx highest_used=%u max_slots=%u\n",
 		__func__, tbl->used_slots[0], tbl->highest_used_slotid,
 		tbl->max_slots);
 	slotid = find_first_zero_bit(tbl->used_slots, tbl->max_slots);
 	if (slotid >= tbl->max_slots)
 		goto out;
 	__set_bit(slotid, tbl->used_slots);
-	if (slotid > tbl->highest_used_slotid)
+	if (slotid > tbl->highest_used_slotid ||
+			tbl->highest_used_slotid == NFS4_NO_SLOT)
 		tbl->highest_used_slotid = slotid;
 	ret_id = slotid;
 out:
@@ -555,7 +553,7 @@ int nfs41_setup_sequence(struct nfs4_session *session,
 {
 	struct nfs4_slot *slot;
 	struct nfs4_slot_table *tbl;
-	u8 slotid;
+	u32 slotid;
 
 	dprintk("--> %s\n", __func__);
 	/* slot already allocated? */
@@ -583,7 +581,7 @@ int nfs41_setup_sequence(struct nfs4_session *session,
 	}
 
 	slotid = nfs4_find_slot(tbl);
-	if (slotid == NFS4_MAX_SLOT_TABLE) {
+	if (slotid == NFS4_NO_SLOT) {
 		rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
 		spin_unlock(&tbl->slot_tbl_lock);
 		dprintk("<-- %s: no free slots\n", __func__);
@@ -5144,7 +5142,7 @@ static int nfs4_init_slot_table(struct nfs4_slot_table *tbl,
 	spin_lock(&tbl->slot_tbl_lock);
 	tbl->max_slots = max_slots;
 	tbl->slots = slot;
-	tbl->highest_used_slotid = -1;  /* no slot is currently used */
+	tbl->highest_used_slotid = NFS4_NO_SLOT;  /* no slot is currently used */
 	spin_unlock(&tbl->slot_tbl_lock);
 	dprintk("%s: tbl=%p slots=%p max_slots=%d\n", __func__,
 		tbl, tbl->slots, tbl->max_slots);
@@ -5196,13 +5194,13 @@ struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
 		return NULL;
 
 	tbl = &session->fc_slot_table;
-	tbl->highest_used_slotid = -1;
+	tbl->highest_used_slotid = NFS4_NO_SLOT;
 	spin_lock_init(&tbl->slot_tbl_lock);
 	rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, "ForeChannel Slot table");
 	init_completion(&tbl->complete);
 
 	tbl = &session->bc_slot_table;
-	tbl->highest_used_slotid = -1;
+	tbl->highest_used_slotid = NFS4_NO_SLOT;
 	spin_lock_init(&tbl->slot_tbl_lock);
 	rpc_init_wait_queue(&tbl->slot_tbl_waitq, "BackChannel Slot table");
 	init_completion(&tbl->complete);

include/linux/nfs_fs_sb.h

@@ -191,6 +191,7 @@ struct nfs_server {
 
 /* maximum number of slots to use */
 #define NFS4_MAX_SLOT_TABLE (128U)
+#define NFS4_NO_SLOT ((u32)-1)
 
 #if defined(CONFIG_NFS_V4)
 
@@ -201,10 +202,10 @@ struct nfs4_slot_table {
 	unsigned long   used_slots[SLOT_TABLE_SZ]; /* used/unused bitmap */
 	spinlock_t	slot_tbl_lock;
 	struct rpc_wait_queue	slot_tbl_waitq;	/* allocators may wait here */
-	int		max_slots;		/* # slots in table */
-	int		highest_used_slotid;	/* sent to server on each SEQ.
+	u32		max_slots;		/* # slots in table */
+	u32		highest_used_slotid;	/* sent to server on each SEQ.
 						 * op for dynamic resizing */
-	int		target_max_slots;	/* Set by CB_RECALL_SLOT as
+	u32		target_max_slots;	/* Set by CB_RECALL_SLOT as
 						 * the new max_slots */
 	struct completion complete;
 };

include/linux/nfs_xdr.h

@@ -181,7 +181,7 @@ struct nfs4_slot {
 
 struct nfs4_sequence_args {
 	struct nfs4_session	*sa_session;
-	u8			sa_slotid;
+	u32			sa_slotid;
 	u8			sa_cache_this;
 };