1 files changed, 32 insertions, 0 deletions

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 4062f7690a33..e5155d9df595 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -361,4 +361,36 @@ out:
         dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
         return status;
 }
+
+/* Reduce the fore channel's max_slots to the target value */
+unsigned nfs4_callback_recallslot(struct cb_recallslotargs *args, void *dummy)
+{
+        struct nfs_client *clp;
+        struct nfs4_slot_table *fc_tbl;
+        int status;
+
+        status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
+        clp = nfs_find_client(args->crsa_addr, 4);
+        if (clp == NULL)
+                goto out;
+
+        dprintk("NFS: CB_RECALL_SLOT request from %s target max slots %d\n",
+                rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR),
+                args->crsa_target_max_slots);
+
+        fc_tbl = &clp->cl_session->fc_slot_table;
+
+        status = htonl(NFS4ERR_BAD_HIGH_SLOT);
+        if (args->crsa_target_max_slots >= fc_tbl->max_slots ||
+            args->crsa_target_max_slots < 1)
+                goto out;
+
+        fc_tbl->target_max_slots = args->crsa_target_max_slots;
+        nfs41_handle_recall_slot(clp);
+        status = htonl(NFS4_OK);
+        nfs_put_client(clp);    /* balance nfs_find_client */
+out:
+        dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
+        return status;
+}
 #endif /* CONFIG_NFS_V4_1 */