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clear-pkgs-linux-iot-lts2018/0779-Kernel-VHM-Refine-the-...

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Zhao Yakui <yakui.zhao@intel.com>
Date: Tue, 18 Dec 2018 09:37:12 +0800
Subject: [PATCH] Kernel/VHM: Refine the usage of spinlock in VHM
The spin lock provides the below APIs to acquire spin_lock.
spin_lock
spin_lock_irq(spin_lock_irqsave)
spin_lock_bh
Now the spinlock in VHM has some problems.
1.The spinlock is acquired by
spin_lock when some spinlock are used in softirq and normal threads. This
has the potential risk. So it should be replaced by spin_lock_bh.
2. The spin_lock_irq is used to acquire the spinlock even when it is not
used in interrupt context. So spin_lock_irq is replaced by spin_lock_bh.
3. the spinlock in vhm_irqfd is only acquired/released in normal process
context. So it is unnecessary to use spin_lock_irq.
Tracked-On: projectacrn/acrn-hypervisor#2085
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Reviewed-by: Shuo Liu <shuo.a.liu@intel.com>
Reviewed-by: Yin, FengWei <fengwei.yin@intel.com>
Tracked-On: PKT-1617
---
drivers/vhm/vhm_ioreq.c | 41 ++++++++++++++++++-----------------------
drivers/vhm/vhm_irqfd.c | 19 +++++++++----------
2 files changed, 27 insertions(+), 33 deletions(-)
diff --git a/drivers/vhm/vhm_ioreq.c b/drivers/vhm/vhm_ioreq.c
index 3f8bd4abe757..8b46f43aaec8 100644
--- a/drivers/vhm/vhm_ioreq.c
+++ b/drivers/vhm/vhm_ioreq.c
@@ -207,7 +207,6 @@ int acrn_ioreq_create_client(unsigned long vmid, ioreq_handler_t handler,
{
struct vhm_vm *vm;
struct ioreq_client *client;
- unsigned long flags;
int client_id;
might_sleep();
@@ -254,9 +253,9 @@ int acrn_ioreq_create_client(unsigned long vmid, ioreq_handler_t handler,
init_waitqueue_head(&client->wq);
/* When it is added to ioreq_client_list, the refcnt is increased */
- spin_lock_irqsave(&vm->ioreq_client_lock, flags);
+ spin_lock_bh(&vm->ioreq_client_lock);
list_add(&client->list, &vm->ioreq_client_list);
- spin_unlock_irqrestore(&vm->ioreq_client_lock, flags);
+ spin_unlock_bh(&vm->ioreq_client_lock);
pr_info("vhm-ioreq: created ioreq client %d\n", client_id);
@@ -279,7 +278,7 @@ void acrn_ioreq_clear_request(struct vhm_vm *vm)
*/
do {
- spin_lock(&vm->ioreq_client_lock);
+ spin_lock_bh(&vm->ioreq_client_lock);
list_for_each(pos, &vm->ioreq_client_list) {
client = container_of(pos, struct ioreq_client, list);
if (vm->ioreq_fallback_client == client->id)
@@ -288,7 +287,7 @@ void acrn_ioreq_clear_request(struct vhm_vm *vm)
if (has_pending)
break;
}
- spin_unlock(&vm->ioreq_client_lock);
+ spin_unlock_bh(&vm->ioreq_client_lock);
if (has_pending)
schedule_timeout_interruptible(HZ / 100);
@@ -360,7 +359,6 @@ static void acrn_ioreq_destroy_client_pervm(struct ioreq_client *client,
struct vhm_vm *vm)
{
struct list_head *pos, *tmp;
- unsigned long flags;
set_bit(IOREQ_CLIENT_DESTROYING, &client->flags);
acrn_ioreq_notify_client(client);
@@ -368,18 +366,18 @@ static void acrn_ioreq_destroy_client_pervm(struct ioreq_client *client,
while (client->vhm_create_kthread && !test_bit(IOREQ_CLIENT_EXIT, &client->flags))
msleep(10);
- spin_lock_irqsave(&client->range_lock, flags);
+ spin_lock_bh(&client->range_lock);
list_for_each_safe(pos, tmp, &client->range_list) {
struct ioreq_range *range =
container_of(pos, struct ioreq_range, list);
list_del(&range->list);
kfree(range);
}
- spin_unlock_irqrestore(&client->range_lock, flags);
+ spin_unlock_bh(&client->range_lock);
- spin_lock_irqsave(&vm->ioreq_client_lock, flags);
+ spin_lock_bh(&vm->ioreq_client_lock);
list_del(&client->list);
- spin_unlock_irqrestore(&vm->ioreq_client_lock, flags);
+ spin_unlock_bh(&vm->ioreq_client_lock);
if (client->id == vm->ioreq_fallback_client)
vm->ioreq_fallback_client = -1;
@@ -414,16 +412,15 @@ EXPORT_SYMBOL_GPL(acrn_ioreq_destroy_client);
static void __attribute__((unused)) dump_iorange(struct ioreq_client *client)
{
struct list_head *pos;
- unsigned long flags;
- spin_lock_irqsave(&client->range_lock, flags);
+ spin_lock_bh(&client->range_lock);
list_for_each(pos, &client->range_list) {
struct ioreq_range *range =
container_of(pos, struct ioreq_range, list);
pr_debug("\tio range: type %d, start 0x%lx, "
"end 0x%lx\n", range->type, range->start, range->end);
}
- spin_unlock_irqrestore(&client->range_lock, flags);
+ spin_unlock_bh(&client->range_lock);
}
/*
@@ -435,7 +432,6 @@ int acrn_ioreq_add_iorange(int client_id, uint32_t type,
{
struct ioreq_client *client;
struct ioreq_range *range;
- unsigned long flags;
if (client_id < 0 || client_id >= MAX_CLIENT) {
pr_err("vhm-ioreq: no client for id %d\n", client_id);
@@ -464,9 +460,9 @@ int acrn_ioreq_add_iorange(int client_id, uint32_t type,
range->start = start;
range->end = end;
- spin_lock_irqsave(&client->range_lock, flags);
+ spin_lock_bh(&client->range_lock);
list_add(&range->list, &client->range_list);
- spin_unlock_irqrestore(&client->range_lock, flags);
+ spin_unlock_bh(&client->range_lock);
acrn_ioreq_put_client(client);
return 0;
@@ -479,7 +475,6 @@ int acrn_ioreq_del_iorange(int client_id, uint32_t type,
struct ioreq_client *client;
struct ioreq_range *range;
struct list_head *pos, *tmp;
- unsigned long flags;
if (client_id < 0 || client_id >= MAX_CLIENT) {
pr_err("vhm-ioreq: no client for id %d\n", client_id);
@@ -498,7 +493,7 @@ int acrn_ioreq_del_iorange(int client_id, uint32_t type,
might_sleep();
- spin_lock_irqsave(&client->range_lock, flags);
+ spin_lock_bh(&client->range_lock);
list_for_each_safe(pos, tmp, &client->range_list) {
range = container_of(pos, struct ioreq_range, list);
if (range->type == type) {
@@ -516,7 +511,7 @@ int acrn_ioreq_del_iorange(int client_id, uint32_t type,
}
}
}
- spin_unlock_irqrestore(&client->range_lock, flags);
+ spin_unlock_bh(&client->range_lock);
acrn_ioreq_put_client(client);
return 0;
@@ -862,7 +857,7 @@ static struct ioreq_client *acrn_ioreq_find_client_by_request(struct vhm_vm *vm,
target_client = 0;
fallback_client = 0;
- spin_lock(&vm->ioreq_client_lock);
+ spin_lock_bh(&vm->ioreq_client_lock);
list_for_each(pos, &vm->ioreq_client_list) {
client = container_of(pos, struct ioreq_client, list);
@@ -879,7 +874,7 @@ static struct ioreq_client *acrn_ioreq_find_client_by_request(struct vhm_vm *vm,
continue;
}
- spin_lock(&client->range_lock);
+ spin_lock_bh(&client->range_lock);
list_for_each(range_pos, &client->range_list) {
range =
container_of(range_pos, struct ioreq_range, list);
@@ -889,12 +884,12 @@ static struct ioreq_client *acrn_ioreq_find_client_by_request(struct vhm_vm *vm,
break;
}
}
- spin_unlock(&client->range_lock);
+ spin_unlock_bh(&client->range_lock);
if (found)
break;
}
- spin_unlock(&vm->ioreq_client_lock);
+ spin_unlock_bh(&vm->ioreq_client_lock);
if (target_client > 0)
return acrn_ioreq_get_client(target_client);
diff --git a/drivers/vhm/vhm_irqfd.c b/drivers/vhm/vhm_irqfd.c
index b8c122d5ea1f..3eb832114fed 100644
--- a/drivers/vhm/vhm_irqfd.c
+++ b/drivers/vhm/vhm_irqfd.c
@@ -171,15 +171,14 @@ static void vhm_irqfd_shutdown(struct acrn_vhm_irqfd *irqfd)
static void vhm_irqfd_shutdown_work(struct work_struct *work)
{
- unsigned long flags;
struct acrn_vhm_irqfd *irqfd =
container_of(work, struct acrn_vhm_irqfd, shutdown);
struct vhm_irqfd_info *info = irqfd->info;
- spin_lock_irqsave(&info->irqfds_lock, flags);
+ spin_lock(&info->irqfds_lock);
if (vhm_irqfd_is_active(info, irqfd))
vhm_irqfd_shutdown(irqfd);
- spin_unlock_irqrestore(&info->irqfds_lock, flags);
+ spin_unlock(&info->irqfds_lock);
}
/*
@@ -251,19 +250,19 @@ static int acrn_irqfd_assign(struct vhm_irqfd_info *info,
init_waitqueue_func_entry(&irqfd->wait, vhm_irqfd_wakeup);
init_poll_funcptr(&irqfd->pt, vhm_irqfd_poll_func);
- spin_lock_irq(&info->irqfds_lock);
+ spin_lock(&info->irqfds_lock);
list_for_each_entry(tmp, &info->irqfds, list) {
if (irqfd->eventfd != tmp->eventfd)
continue;
/* This fd is used for another irq already. */
ret = -EBUSY;
- spin_unlock_irq(&info->irqfds_lock);
+ spin_unlock(&info->irqfds_lock);
goto fail;
}
list_add_tail(&irqfd->list, &info->irqfds);
- spin_unlock_irq(&info->irqfds_lock);
+ spin_unlock(&info->irqfds_lock);
/* Check the pending event in this stage */
events = f.file->f_op->poll(f.file, &irqfd->pt);
@@ -294,7 +293,7 @@ static int acrn_irqfd_deassign(struct vhm_irqfd_info *info,
if (IS_ERR(eventfd))
return PTR_ERR(eventfd);
- spin_lock_irq(&info->irqfds_lock);
+ spin_lock(&info->irqfds_lock);
list_for_each_entry_safe(irqfd, tmp, &info->irqfds, list) {
if (irqfd->eventfd == eventfd) {
@@ -303,7 +302,7 @@ static int acrn_irqfd_deassign(struct vhm_irqfd_info *info,
}
}
- spin_unlock_irq(&info->irqfds_lock);
+ spin_unlock(&info->irqfds_lock);
eventfd_ctx_put(eventfd);
return 0;
@@ -371,10 +370,10 @@ void acrn_irqfd_deinit(uint16_t vmid)
destroy_workqueue(info->wq);
- spin_lock_irq(&info->irqfds_lock);
+ spin_lock(&info->irqfds_lock);
list_for_each_entry_safe(irqfd, tmp, &info->irqfds, list)
vhm_irqfd_shutdown(irqfd);
- spin_unlock_irq(&info->irqfds_lock);
+ spin_unlock(&info->irqfds_lock);
/* put one more to release it */
put_irqfd_info(info);
--
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