| Subject: net: Use cpu_chill() instead of cpu_relax() |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Wed, 07 Mar 2012 21:10:04 +0100 |
| |
| 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> |
| Cc: stable-rt@vger.kernel.org |
| --- |
| net/packet/af_packet.c | 5 +++-- |
| net/rds/ib_rdma.c | 3 ++- |
| 2 files changed, 5 insertions(+), 3 deletions(-) |
| |
| Index: linux-stable/net/packet/af_packet.c |
| =================================================================== |
| --- linux-stable.orig/net/packet/af_packet.c |
| +++ linux-stable/net/packet/af_packet.c |
| @@ -88,6 +88,7 @@ |
| #include <linux/virtio_net.h> |
| #include <linux/errqueue.h> |
| #include <linux/net_tstamp.h> |
| +#include <linux/delay.h> |
| |
| #ifdef CONFIG_INET |
| #include <net/inet_common.h> |
| @@ -666,7 +667,7 @@ static void prb_retire_rx_blk_timer_expi |
| if (BLOCK_NUM_PKTS(pbd)) { |
| while (atomic_read(&pkc->blk_fill_in_prog)) { |
| /* Waiting for skb_copy_bits to finish... */ |
| - cpu_relax(); |
| + cpu_chill(); |
| } |
| } |
| |
| @@ -920,7 +921,7 @@ static void prb_retire_current_block(str |
| 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); |
| Index: linux-stable/net/rds/ib_rdma.c |
| =================================================================== |
| --- linux-stable.orig/net/rds/ib_rdma.c |
| +++ linux-stable/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.h" |
| #include "ib.h" |
| @@ -286,7 +287,7 @@ static inline void wait_clean_list_grace |
| for_each_online_cpu(cpu) { |
| flag = &per_cpu(clean_list_grace, cpu); |
| while (test_bit(CLEAN_LIST_BUSY_BIT, flag)) |
| - cpu_relax(); |
| + cpu_chill(); |
| } |
| } |
| |