SUNRPC: Set memalloc_nofs_save() on all rpciod/xprtiod jobs

Set memalloc_nofs_save() on all the rpciod/xprtiod jobs so that we
ensure memory allocations for asynchronous rpc calls don't ever end
up recursing back to the NFS layer for memory reclaim.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

net/sunrpc/sched.c

@@ -19,6 +19,7 @@
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
 #include <linux/freezer.h>
+#include <linux/sched/mm.h>
 
 #include <linux/sunrpc/clnt.h>
 
@@ -902,7 +903,10 @@ void rpc_execute(struct rpc_task *task)
 
 static void rpc_async_schedule(struct work_struct *work)
 {
+	unsigned int pflags = memalloc_nofs_save();
+
 	__rpc_execute(container_of(work, struct rpc_task, u.tk_work));
+	memalloc_nofs_restore(pflags);
 }
 
 /**
@@ -1067,7 +1071,10 @@ static void rpc_free_task(struct rpc_task *task)
 
 static void rpc_async_release(struct work_struct *work)
 {
+	unsigned int pflags = memalloc_nofs_save();
+
 	rpc_free_task(container_of(work, struct rpc_task, u.tk_work));
+	memalloc_nofs_restore(pflags);
 }
 
 static void rpc_release_resources_task(struct rpc_task *task)

net/sunrpc/xprt.c

@@ -49,6 +49,7 @@
 #include <linux/sunrpc/metrics.h>
 #include <linux/sunrpc/bc_xprt.h>
 #include <linux/rcupdate.h>
+#include <linux/sched/mm.h>
 
 #include <trace/events/sunrpc.h>
 
@@ -643,11 +644,13 @@ static void xprt_autoclose(struct work_struct *work)
 {
 	struct rpc_xprt *xprt =
 		container_of(work, struct rpc_xprt, task_cleanup);
+	unsigned int pflags = memalloc_nofs_save();
 
 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
 	xprt->ops->close(xprt);
 	xprt_release_write(xprt, NULL);
 	wake_up_bit(&xprt->state, XPRT_LOCKED);
+	memalloc_nofs_restore(pflags);
 }
 
 /**

net/sunrpc/xprtsock.c

@@ -50,6 +50,7 @@
 #include <linux/bvec.h>
 #include <linux/highmem.h>
 #include <linux/uio.h>
+#include <linux/sched/mm.h>
 
 #include <trace/events/sunrpc.h>
 
@@ -680,7 +681,10 @@ static void xs_stream_data_receive_workfn(struct work_struct *work)
 {
 	struct sock_xprt *transport =
 		container_of(work, struct sock_xprt, recv_worker);
+	unsigned int pflags = memalloc_nofs_save();
+
 	xs_stream_data_receive(transport);
+	memalloc_nofs_restore(pflags);
 }
 
 static void
@@ -1378,7 +1382,10 @@ static void xs_udp_data_receive_workfn(struct work_struct *work)
 {
 	struct sock_xprt *transport =
 		container_of(work, struct sock_xprt, recv_worker);
+	unsigned int pflags = memalloc_nofs_save();
+
 	xs_udp_data_receive(transport);
+	memalloc_nofs_restore(pflags);
 }
 
 /**
@@ -1869,7 +1876,6 @@ static int xs_local_finish_connecting(struct rpc_xprt *xprt,
 		sk->sk_write_space = xs_udp_write_space;
 		sock_set_flag(sk, SOCK_FASYNC);
 		sk->sk_error_report = xs_error_report;
-		sk->sk_allocation = GFP_NOIO;
 
 		xprt_clear_connected(xprt);
 
@@ -2057,7 +2063,6 @@ static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
 		sk->sk_data_ready = xs_data_ready;
 		sk->sk_write_space = xs_udp_write_space;
 		sock_set_flag(sk, SOCK_FASYNC);
-		sk->sk_allocation = GFP_NOIO;
 
 		xprt_set_connected(xprt);
 
@@ -2220,7 +2225,6 @@ static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
 		sk->sk_write_space = xs_tcp_write_space;
 		sock_set_flag(sk, SOCK_FASYNC);
 		sk->sk_error_report = xs_error_report;
-		sk->sk_allocation = GFP_NOIO;
 
 		/* socket options */
 		sock_reset_flag(sk, SOCK_LINGER);