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Subject[PATCH 10/10] Xen: update pcpu online/offline logic
Date
From 1e59d2ec2ff93b42c86d18c7cc9432ca2172a795 Mon Sep 17 00:00:00 2001
From: Liu Jinsong <jinsong.liu@intel.com>
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@intel.com>
Signed-off-by: Jiang, Yunhong <yunhong.jiang@intel.com>
---
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[unhandled content-type:application/octet-stream]
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