[Xen-devel] [PATCH 10/10] Xen: update pcpu online/offline logic

["Liu, Jinsong" <jinsong.liu@xxxxxxxxx>]

>From 1e59d2ec2ff93b42c86d18c7cc9432ca2172a795 Mon Sep 17 00:00:00 2001
From: Liu Jinsong <jinsong.liu@xxxxxxxxx>
Date: Wed, 14 Dec 2011 21:06:11 +0800
Subject: [PATCH 10/10] Xen: update pcpu online/offline logic

This patch update pcpu online/offline logic.

It closes cpu0's /sys/.../xen_pcpu0/online authority to user.
It also simplifies pcpu sync by removing redundant logic.

Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
Signed-off-by: Jiang, Yunhong <yunhong.jiang@xxxxxxxxx>
---
 drivers/xen/pcpu.c |   71 ++++++++++++++--------------------------------------
 1 files changed, 19 insertions(+), 52 deletions(-)

diff --git a/drivers/xen/pcpu.c b/drivers/xen/pcpu.c
index 6d1a770..1d32784 100644
--- a/drivers/xen/pcpu.c
+++ b/drivers/xen/pcpu.c
@@ -24,7 +24,6 @@ static RAW_NOTIFIER_HEAD(xen_pcpu_chain);
 
 struct xen_pcpus {
        struct list_head list;
-       int present;
 };
 static struct xen_pcpus xen_pcpus;
 
@@ -189,9 +188,13 @@ static int pcpu_sysdev_init(struct pcpu *cpu)
                kfree(cpu);
                return -1;
        }
-       sysdev_create_file(&cpu->sysdev, &attr_online);
        sysdev_create_file(&cpu->sysdev, &attr_apic_id);
        sysdev_create_file(&cpu->sysdev, &attr_acpi_id);
+
+       /* Not open cpu0 online access to user */
+       if (cpu->sysdev.id)
+               sysdev_create_file(&cpu->sysdev, &attr_online);
+
        return 0;
 }
 
@@ -239,17 +242,10 @@ static struct pcpu *init_pcpu(struct xenpf_pcpuinfo *info)
        return pcpu;
 }
 
-#define PCPU_NO_CHANGE                 0
-#define PCPU_ADDED                     1
-#define PCPU_ONLINE_OFFLINE            2
-#define PCPU_REMOVED                   3
 /*
  * Caller should hold the pcpu lock
- * < 0: Something wrong
- * 0: No changes
- * > 0: State changed
  */
-static struct pcpu *_sync_pcpu(int cpu_num, int *max_id, int *result)
+static int _sync_pcpu(int cpu_num, int *max_id)
 {
        struct pcpu *pcpu = NULL;
        struct xenpf_pcpuinfo *info;
@@ -259,14 +255,12 @@ static struct pcpu *_sync_pcpu(int cpu_num, int *max_id, 
int *result)
        };
        int ret;
 
-       *result = -1;
-
        info = &op.u.pcpu_info;
        info->xen_cpuid = cpu_num;
 
        ret = HYPERVISOR_dom0_op(&op);
        if (ret)
-               return NULL;
+               return -1;
 
        if (max_id)
                *max_id = op.u.pcpu_info.max_present;
@@ -275,28 +269,24 @@ static struct pcpu *_sync_pcpu(int cpu_num, int *max_id, 
int *result)
 
        if (info->flags & XEN_PCPU_FLAGS_INVALID) {
                /* The pcpu has been removed */
-               *result = PCPU_NO_CHANGE;
                if (pcpu) {
                        raw_notifier_call_chain(&xen_pcpu_chain,
                          XEN_PCPU_REMOVE,
                          (void *)(long)pcpu->xen_id);
                        xen_pcpu_free(pcpu);
-                       *result = PCPU_REMOVED;
                }
-               return NULL;
+               return 0;
        }
 
 
        if (!pcpu) {
-               *result = PCPU_ADDED;
                pcpu = init_pcpu(info);
                if (pcpu == NULL) {
                        printk(KERN_WARNING "Failed to init pcpu %x\n",
                          info->xen_cpuid);
-                         *result = -1;
+                       return -1;
                }
        } else {
-               *result = PCPU_NO_CHANGE;
                /*
                 * Old PCPU is replaced with a new pcpu, this means
                 * several virq is missed, will it happen?
@@ -307,10 +297,10 @@ static struct pcpu *_sync_pcpu(int cpu_num, int *max_id, 
int *result)
                        pcpu->apic_id = info->apic_id;
                        pcpu->acpi_id = info->acpi_id;
                }
-               if (xen_pcpu_online_check(info, pcpu))
-                       *result = PCPU_ONLINE_OFFLINE;
+               xen_pcpu_online_check(info, pcpu);
        }
-       return pcpu;
+
+       return 0;
 }
 
 int xen_pcpu_index(uint32_t id, int is_acpiid)
@@ -353,50 +343,27 @@ static int xen_sync_pcpus(void)
        /*
         * Boot cpu always have cpu_id 0 in xen
         */
-       int cpu_num = 0, max_id = 0, result = 0, present = 0;
+       int cpu_num = 0, max_id = 0, ret = 0;
        struct list_head *elem, *tmp;
        struct pcpu *pcpu;
 
        get_pcpu_lock();
 
-       while ((result >= 0) && (cpu_num <= max_id)) {
-               pcpu = _sync_pcpu(cpu_num, &max_id, &result);
-
-               printk(KERN_DEBUG "sync cpu %x get result %x max_id %x\n",
-                       cpu_num, result, max_id);
-
-               switch (result) {
-               case PCPU_NO_CHANGE:
-                       if (pcpu)
-                               present++;
-                       break;
-               case PCPU_ADDED:
-               case PCPU_ONLINE_OFFLINE:
-                       present++;
-               case PCPU_REMOVED:
-                       break;
-               default:
-                       printk(KERN_WARNING "Failed to sync pcpu %x\n",
-                         cpu_num);
-                       break;
-
-               }
+       while (!ret && (cpu_num <= max_id)) {
+               ret = _sync_pcpu(cpu_num, &max_id);
                cpu_num++;
        }
 
-       if (result < 0) {
+       if (ret < 0) {
                list_for_each_safe(elem, tmp, &xen_pcpus.list) {
                        pcpu = list_entry(elem, struct pcpu, pcpu_list);
                        xen_pcpu_free(pcpu);
                }
-               present = 0;
        }
 
-       xen_pcpus.present = present;
-
        put_pcpu_lock();
 
-       return 0;
+       return ret;
 }
 
 static void xen_pcpu_dpc(struct work_struct *work)
@@ -436,10 +403,10 @@ static int __init xen_pcpu_init(void)
        }
 
        INIT_LIST_HEAD(&xen_pcpus.list);
-       xen_pcpus.present = 0;
 
        xen_sync_pcpus();
-       if (xen_pcpus.present > 0)
+
+       if (!list_empty(&xen_pcpus.list))
                err = bind_virq_to_irqhandler(VIRQ_PCPU_STATE,
                        0, xen_pcpu_interrupt, 0, "pcpu", NULL);
        if (err < 0)
-- 
1.6.5.6

Attachment: 0010-Xen-update-pcpu-online-offline-logic.patch
Description: 0010-Xen-update-pcpu-online-offline-logic.patch

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel