From 5f998852deb9bb47c44465113e43ec601ed3f6b2 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 7 Mar 2012 21:10:04 +0100
Subject: [PATCH 309/418] net: Use cpu_chill() instead of cpu_relax()

Retry loops on RT might loop forever when the modifying side was
preempted. Use cpu_chill() instead of cpu_relax() to let the system
make progress.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 net/packet/af_packet.c | 5 +++--
 net/rds/ib_rdma.c      | 3 ++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 4fe2e34522d6..8bdf6c301261 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -63,6 +63,7 @@
 #include <linux/if_packet.h>
 #include <linux/wireless.h>
 #include <linux/kernel.h>
+#include <linux/delay.h>
 #include <linux/kmod.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
@@ -707,7 +708,7 @@ static void prb_retire_rx_blk_timer_expired(unsigned long data)
 	if (BLOCK_NUM_PKTS(pbd)) {
 		while (atomic_read(&pkc->blk_fill_in_prog)) {
 			/* Waiting for skb_copy_bits to finish... */
-			cpu_relax();
+			cpu_chill();
 		}
 	}
 
@@ -969,7 +970,7 @@ static void prb_retire_current_block(struct tpacket_kbdq_core *pkc,
 		if (!(status & TP_STATUS_BLK_TMO)) {
 			while (atomic_read(&pkc->blk_fill_in_prog)) {
 				/* Waiting for skb_copy_bits to finish... */
-				cpu_relax();
+				cpu_chill();
 			}
 		}
 		prb_close_block(pkc, pbd, po, status);
diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c
index 9a3c54e659e9..2a95f1d587ac 100644
--- a/net/rds/ib_rdma.c
+++ b/net/rds/ib_rdma.c
@@ -34,6 +34,7 @@
 #include <linux/slab.h>
 #include <linux/rculist.h>
 #include <linux/llist.h>
+#include <linux/delay.h>
 
 #include "rds_single_path.h"
 #include "ib_mr.h"
@@ -210,7 +211,7 @@ static inline void wait_clean_list_grace(void)
 	for_each_online_cpu(cpu) {
 		flag = &per_cpu(clean_list_grace, cpu);
 		while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
-			cpu_relax();
+			cpu_chill();
 	}
 }
 
-- 
2.17.1