[Xen-changelog] [linux-2.6.18-xen] Kernel threads need to be aware of freeze request, by checking in

["Xen patchbot-linux-2.6.18-xen" <patchbot-linux-2.6.18-xen@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1181573766 -3600
# Node ID c09686d2bbffa5ec2152f685df0eaa090ddddd83
# Parent  07a5f92187ac57ffbd107571b2019be2f53bda98
Kernel threads need to be aware of freeze request, by checking in
their main loop.

xenbus/xenwatch threads are special with PF_NOFREEZE, since we're sure
that they do nothing to block other native device drivers.

Signed-off-by Ke Yu <ke.yu@xxxxxxxxx>
Signed-off-by Kevin Tian <kevin.tian@xxxxxxxxx>
---
 drivers/xen/blkback/blkback.c  |    3 +++
 drivers/xen/xenbus/xenbus_xs.c |    2 ++
 2 files changed, 5 insertions(+)

diff -r 07a5f92187ac -r c09686d2bbff drivers/xen/blkback/blkback.c
--- a/drivers/xen/blkback/blkback.c     Mon Jun 11 15:53:26 2007 +0100
+++ b/drivers/xen/blkback/blkback.c     Mon Jun 11 15:56:06 2007 +0100
@@ -208,6 +208,9 @@ int blkif_schedule(void *arg)
                printk(KERN_DEBUG "%s: started\n", current->comm);
 
        while (!kthread_should_stop()) {
+               if(try_to_freeze())
+                       continue;
+            
                wait_event_interruptible(
                        blkif->wq,
                        blkif->waiting_reqs || kthread_should_stop());
diff -r 07a5f92187ac -r c09686d2bbff drivers/xen/xenbus/xenbus_xs.c
--- a/drivers/xen/xenbus/xenbus_xs.c    Mon Jun 11 15:53:26 2007 +0100
+++ b/drivers/xen/xenbus/xenbus_xs.c    Mon Jun 11 15:56:06 2007 +0100
@@ -718,6 +718,7 @@ static int xenwatch_thread(void *unused)
        struct list_head *ent;
        struct xs_stored_msg *msg;
 
+       current->flags |= PF_NOFREEZE;
        for (;;) {
                wait_event_interruptible(watch_events_waitq,
                                         !list_empty(&watch_events));
@@ -836,6 +837,7 @@ static int xenbus_thread(void *unused)
 {
        int err;
 
+       current->flags |= PF_NOFREEZE;
        for (;;) {
                err = process_msg();
                if (err)

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