Update Linux to v5.10.109

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz

Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 3c50d18..7325592 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -38,6 +38,7 @@
 #include "nfsd.h"
 #include "state.h"
 #include "netns.h"
+#include "trace.h"
 #include "xdr4cb.h"
 #include "xdr4.h"
 
@@ -823,7 +824,41 @@
 static int max_cb_time(struct net *net)
 {
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
-	return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
+
+	/*
+	 * nfsd4_lease is set to at most one hour in __nfsd4_write_time,
+	 * so we can use 32-bit math on it. Warn if that assumption
+	 * ever stops being true.
+	 */
+	if (WARN_ON_ONCE(nn->nfsd4_lease > 3600))
+		return 360 * HZ;
+
+	return max(((u32)nn->nfsd4_lease)/10, 1u) * HZ;
+}
+
+static struct workqueue_struct *callback_wq;
+
+static bool nfsd4_queue_cb(struct nfsd4_callback *cb)
+{
+	return queue_work(callback_wq, &cb->cb_work);
+}
+
+static void nfsd41_cb_inflight_begin(struct nfs4_client *clp)
+{
+	atomic_inc(&clp->cl_cb_inflight);
+}
+
+static void nfsd41_cb_inflight_end(struct nfs4_client *clp)
+{
+
+	if (atomic_dec_and_test(&clp->cl_cb_inflight))
+		wake_up_var(&clp->cl_cb_inflight);
+}
+
+static void nfsd41_cb_inflight_wait_complete(struct nfs4_client *clp)
+{
+	wait_var_event(&clp->cl_cb_inflight,
+			!atomic_read(&clp->cl_cb_inflight));
 }
 
 static const struct cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
@@ -870,16 +905,20 @@
 
 	if (clp->cl_minorversion == 0) {
 		if (!clp->cl_cred.cr_principal &&
-				(clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
+		    (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5)) {
+			trace_nfsd_cb_setup_err(clp, -EINVAL);
 			return -EINVAL;
+		}
 		args.client_name = clp->cl_cred.cr_principal;
 		args.prognumber	= conn->cb_prog;
 		args.protocol = XPRT_TRANSPORT_TCP;
 		args.authflavor = clp->cl_cred.cr_flavor;
 		clp->cl_cb_ident = conn->cb_ident;
 	} else {
-		if (!conn->cb_xprt)
+		if (!conn->cb_xprt) {
+			trace_nfsd_cb_setup_err(clp, -EINVAL);
 			return -EINVAL;
+		}
 		clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 		clp->cl_cb_session = ses;
 		args.bc_xprt = conn->cb_xprt;
@@ -891,32 +930,27 @@
 	/* Create RPC client */
 	client = rpc_create(&args);
 	if (IS_ERR(client)) {
-		dprintk("NFSD: couldn't create callback client: %ld\n",
-			PTR_ERR(client));
+		trace_nfsd_cb_setup_err(clp, PTR_ERR(client));
 		return PTR_ERR(client);
 	}
 	cred = get_backchannel_cred(clp, client, ses);
 	if (!cred) {
+		trace_nfsd_cb_setup_err(clp, -ENOMEM);
 		rpc_shutdown_client(client);
 		return -ENOMEM;
 	}
 	clp->cl_cb_client = client;
 	clp->cl_cb_cred = cred;
+	trace_nfsd_cb_setup(clp);
 	return 0;
 }
 
-static void warn_no_callback_path(struct nfs4_client *clp, int reason)
-{
-	dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
-		(int)clp->cl_name.len, clp->cl_name.data, reason);
-}
-
 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 {
 	if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 		return;
 	clp->cl_cb_state = NFSD4_CB_DOWN;
-	warn_no_callback_path(clp, reason);
+	trace_nfsd_cb_state(clp);
 }
 
 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
@@ -924,27 +958,37 @@
 	if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 		return;
 	clp->cl_cb_state = NFSD4_CB_FAULT;
-	warn_no_callback_path(clp, reason);
+	trace_nfsd_cb_state(clp);
 }
 
 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 {
 	struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 
+	trace_nfsd_cb_done(clp, task->tk_status);
 	if (task->tk_status)
 		nfsd4_mark_cb_down(clp, task->tk_status);
-	else
+	else {
 		clp->cl_cb_state = NFSD4_CB_UP;
+		trace_nfsd_cb_state(clp);
+	}
+}
+
+static void nfsd4_cb_probe_release(void *calldata)
+{
+	struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
+
+	nfsd41_cb_inflight_end(clp);
+
 }
 
 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 	/* XXX: release method to ensure we set the cb channel down if
 	 * necessary on early failure? */
 	.rpc_call_done = nfsd4_cb_probe_done,
+	.rpc_release = nfsd4_cb_probe_release,
 };
 
-static struct workqueue_struct *callback_wq;
-
 /*
  * Poke the callback thread to process any updates to the callback
  * parameters, and send a null probe.
@@ -952,6 +996,7 @@
 void nfsd4_probe_callback(struct nfs4_client *clp)
 {
 	clp->cl_cb_state = NFSD4_CB_UNKNOWN;
+	trace_nfsd_cb_state(clp);
 	set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 	nfsd4_run_cb(&clp->cl_cb_null);
 }
@@ -968,6 +1013,7 @@
 	spin_lock(&clp->cl_lock);
 	memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 	spin_unlock(&clp->cl_lock);
+	trace_nfsd_cb_state(clp);
 }
 
 /*
@@ -975,9 +1021,12 @@
  * If the slot is available, then mark it busy.  Otherwise, set the
  * thread for sleeping on the callback RPC wait queue.
  */
-static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
+static bool nfsd41_cb_get_slot(struct nfsd4_callback *cb, struct rpc_task *task)
 {
-	if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
+	struct nfs4_client *clp = cb->cb_clp;
+
+	if (!cb->cb_holds_slot &&
+	    test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 		rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 		/* Race breaker */
 		if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
@@ -986,9 +1035,31 @@
 		}
 		rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
 	}
+	cb->cb_holds_slot = true;
 	return true;
 }
 
+static void nfsd41_cb_release_slot(struct nfsd4_callback *cb)
+{
+	struct nfs4_client *clp = cb->cb_clp;
+
+	if (cb->cb_holds_slot) {
+		cb->cb_holds_slot = false;
+		clear_bit(0, &clp->cl_cb_slot_busy);
+		rpc_wake_up_next(&clp->cl_cb_waitq);
+	}
+}
+
+static void nfsd41_destroy_cb(struct nfsd4_callback *cb)
+{
+	struct nfs4_client *clp = cb->cb_clp;
+
+	nfsd41_cb_release_slot(cb);
+	if (cb->cb_ops && cb->cb_ops->release)
+		cb->cb_ops->release(cb);
+	nfsd41_cb_inflight_end(clp);
+}
+
 /*
  * TODO: cb_sequence should support referring call lists, cachethis, multiple
  * slots, and mark callback channel down on communication errors.
@@ -1005,11 +1076,8 @@
 	 */
 	cb->cb_seq_status = 1;
 	cb->cb_status = 0;
-	if (minorversion) {
-		if (!cb->cb_holds_slot && !nfsd41_cb_get_slot(clp, task))
-			return;
-		cb->cb_holds_slot = true;
-	}
+	if (minorversion && !nfsd41_cb_get_slot(cb, task))
+		return;
 	rpc_call_start(task);
 }
 
@@ -1051,7 +1119,7 @@
 		break;
 	case -ESERVERFAULT:
 		++session->se_cb_seq_nr;
-		/* Fall through */
+		fallthrough;
 	case 1:
 	case -NFS4ERR_BADSESSION:
 		nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
@@ -1072,13 +1140,12 @@
 		}
 		break;
 	default:
+		nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
 		dprintk("%s: unprocessed error %d\n", __func__,
 			cb->cb_seq_status);
 	}
 
-	cb->cb_holds_slot = false;
-	clear_bit(0, &clp->cl_cb_slot_busy);
-	rpc_wake_up_next(&clp->cl_cb_waitq);
+	nfsd41_cb_release_slot(cb);
 	dprintk("%s: freed slot, new seqid=%d\n", __func__,
 		clp->cl_cb_session->se_cb_seq_nr);
 
@@ -1091,8 +1158,10 @@
 		ret = false;
 	goto out;
 need_restart:
-	task->tk_status = 0;
-	cb->cb_need_restart = true;
+	if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
+		task->tk_status = 0;
+		cb->cb_need_restart = true;
+	}
 	return false;
 }
 
@@ -1101,8 +1170,7 @@
 	struct nfsd4_callback *cb = calldata;
 	struct nfs4_client *clp = cb->cb_clp;
 
-	dprintk("%s: minorversion=%d\n", __func__,
-		clp->cl_minorversion);
+	trace_nfsd_cb_done(clp, task->tk_status);
 
 	if (!nfsd4_cb_sequence_done(task, cb))
 		return;
@@ -1135,9 +1203,9 @@
 	struct nfsd4_callback *cb = calldata;
 
 	if (cb->cb_need_restart)
-		nfsd4_run_cb(cb);
+		nfsd4_queue_cb(cb);
 	else
-		cb->cb_ops->release(cb);
+		nfsd41_destroy_cb(cb);
 
 }
 
@@ -1171,6 +1239,7 @@
 	 */
 	nfsd4_run_cb(&clp->cl_cb_null);
 	flush_workqueue(callback_wq);
+	nfsd41_cb_inflight_wait_complete(clp);
 }
 
 /* requires cl_lock: */
@@ -1188,6 +1257,12 @@
 	return NULL;
 }
 
+/*
+ * Note there isn't a lot of locking in this code; instead we depend on
+ * the fact that it is run from the callback_wq, which won't run two
+ * work items at once.  So, for example, callback_wq handles all access
+ * of cl_cb_client and all calls to rpc_create or rpc_shutdown_client.
+ */
 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
 {
 	struct nfs4_cb_conn conn;
@@ -1201,6 +1276,7 @@
 	 * kill the old client:
 	 */
 	if (clp->cl_cb_client) {
+		trace_nfsd_cb_shutdown(clp);
 		rpc_shutdown_client(clp->cl_cb_client);
 		clp->cl_cb_client = NULL;
 		put_cred(clp->cl_cb_cred);
@@ -1246,6 +1322,8 @@
 	struct rpc_clnt *clnt;
 	int flags;
 
+	trace_nfsd_cb_work(clp, cb->cb_msg.rpc_proc->p_name);
+
 	if (cb->cb_need_restart) {
 		cb->cb_need_restart = false;
 	} else {
@@ -1259,8 +1337,7 @@
 	clnt = clp->cl_cb_client;
 	if (!clnt) {
 		/* Callback channel broken, or client killed; give up: */
-		if (cb->cb_ops && cb->cb_ops->release)
-			cb->cb_ops->release(cb);
+		nfsd41_destroy_cb(cb);
 		return;
 	}
 
@@ -1269,6 +1346,7 @@
 	 */
 	if (!cb->cb_ops && clp->cl_minorversion) {
 		clp->cl_cb_state = NFSD4_CB_UP;
+		nfsd41_destroy_cb(cb);
 		return;
 	}
 
@@ -1295,5 +1373,9 @@
 
 void nfsd4_run_cb(struct nfsd4_callback *cb)
 {
-	queue_work(callback_wq, &cb->cb_work);
+	struct nfs4_client *clp = cb->cb_clp;
+
+	nfsd41_cb_inflight_begin(clp);
+	if (!nfsd4_queue_cb(cb))
+		nfsd41_cb_inflight_end(clp);
 }