[PATCH 5.10.y] nfsd: Don't call freezable_schedule_timeout() after each successful page allocation in svc_alloc_arg().

[Kuniyuki Iwashima <kuniyu@amazon.com>]

When commit 390390240145 ("nfsd: don't allow nfsd threads to be
signalled.") is backported to 5.10, it was adjusted considering commit
3feac2b55293 ("sunrpc: exclude from freezer when waiting for requests:").

However, 3feac2b55293 is based on commit f6e70aab9dfe ("SUNRPC: refresh
rq_pages using a bulk page allocator"), which converted page-by-page
allocation to a batch allocation, so schedule_timeout() is placed
un-nested.

As a result, the backported commit 7229200f6866 ("nfsd: don't allow nfsd
threads to be signalled.") placed freezable_schedule_timeout() in the wrong
place.

Now, freezable_schedule_timeout() is called after every successful page
allocation, and we see 30%+ performance regression on 5.10.220 in our
test suite.

Let's move it to the correct place so that freezable_schedule_timeout()
is called only when page allocation fails.

Fixes: 7229200f6866 ("nfsd: don't allow nfsd threads to be signalled.")
Reported-by: Hughdan Liu <hughliu@amazon.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/sunrpc/svc_xprt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index d1eacf3358b8..60782504ad3e 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -679,8 +679,8 @@ static int svc_alloc_arg(struct svc_rqst *rqstp)
 					set_current_state(TASK_RUNNING);
 					return -EINTR;
 				}
+				freezable_schedule_timeout(msecs_to_jiffies(500));
 			}
-			freezable_schedule_timeout(msecs_to_jiffies(500));
 			rqstp->rq_pages[i] = p;
 		}
 	rqstp->rq_page_end = &rqstp->rq_pages[i];
-- 
2.30.2