[AF_IUCV/IUCV]: smp_call_function deadlock
Calling smp_call_function can lead to a deadlock if it is called from tasklet context. Fixing this deadlock requires to move the smp_call_function from the tasklet context to a work queue. To do that queue the path pending interrupts to a separate list and move the path cleanup out of iucv_path_sever to iucv_path_connect and iucv_path_pending. This creates a new requirement for iucv_path_connect: it may not be called from tasklet context anymore. Also fixed compile problem for CONFIG_HOTPLUG_CPU=n and another one when walking the cpu_online mask. When doing this, we must disable cpu hotplug. Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Martin Schwidefsky
David S. Miller
Родитель
d0772b70fa
Коммит
04b090d50c
|
|
@ -16,7 +16,7 @@
|
|||
* completed a register, it can exploit the other functions.
|
||||
* For furthur reference on all IUCV functionality, refer to the
|
||||
* CP Programming Services book, also available on the web thru
|
||||
* www.ibm.com/s390/vm/pubs, manual # SC24-5760
|
||||
* www.vm.ibm.com/pubs, manual # SC24-6084
|
||||
*
|
||||
* Definition of Return Codes
|
||||
* - All positive return codes including zero are reflected back
|
||||
|
|
|
|||
205
net/iucv/iucv.c
205
net/iucv/iucv.c
|
|
@ -90,20 +90,43 @@ struct iucv_irq_data {
|
|||
u32 res2[8];
|
||||
};
|
||||
|
||||
struct iucv_work {
|
||||
struct iucv_irq_list {
|
||||
struct list_head list;
|
||||
struct iucv_irq_data data;
|
||||
};
|
||||
|
||||
static LIST_HEAD(iucv_work_queue);
|
||||
static DEFINE_SPINLOCK(iucv_work_lock);
|
||||
|
||||
static struct iucv_irq_data *iucv_irq_data;
|
||||
static cpumask_t iucv_buffer_cpumask = CPU_MASK_NONE;
|
||||
static cpumask_t iucv_irq_cpumask = CPU_MASK_NONE;
|
||||
|
||||
static void iucv_tasklet_handler(unsigned long);
|
||||
static DECLARE_TASKLET(iucv_tasklet, iucv_tasklet_handler,0);
|
||||
/*
|
||||
* Queue of interrupt buffers lock for delivery via the tasklet
|
||||
* (fast but can't call smp_call_function).
|
||||
*/
|
||||
static LIST_HEAD(iucv_task_queue);
|
||||
|
||||
/*
|
||||
* The tasklet for fast delivery of iucv interrupts.
|
||||
*/
|
||||
static void iucv_tasklet_fn(unsigned long);
|
||||
static DECLARE_TASKLET(iucv_tasklet, iucv_tasklet_fn,0);
|
||||
|
||||
/*
|
||||
* Queue of interrupt buffers for delivery via a work queue
|
||||
* (slower but can call smp_call_function).
|
||||
*/
|
||||
static LIST_HEAD(iucv_work_queue);
|
||||
|
||||
/*
|
||||
* The work element to deliver path pending interrupts.
|
||||
*/
|
||||
static void iucv_work_fn(struct work_struct *work);
|
||||
static DECLARE_WORK(iucv_work, iucv_work_fn);
|
||||
|
||||
/*
|
||||
* Spinlock protecting task and work queue.
|
||||
*/
|
||||
static DEFINE_SPINLOCK(iucv_queue_lock);
|
||||
|
||||
enum iucv_command_codes {
|
||||
IUCV_QUERY = 0,
|
||||
|
|
@ -147,10 +170,10 @@ static unsigned long iucv_max_pathid;
|
|||
static DEFINE_SPINLOCK(iucv_table_lock);
|
||||
|
||||
/*
|
||||
* iucv_tasklet_cpu: contains the number of the cpu executing the tasklet.
|
||||
* Needed for iucv_path_sever called from tasklet.
|
||||
* iucv_active_cpu: contains the number of the cpu executing the tasklet
|
||||
* or the work handler. Needed for iucv_path_sever called from tasklet.
|
||||
*/
|
||||
static int iucv_tasklet_cpu = -1;
|
||||
static int iucv_active_cpu = -1;
|
||||
|
||||
/*
|
||||
* Mutex and wait queue for iucv_register/iucv_unregister.
|
||||
|
|
@ -449,17 +472,19 @@ static void iucv_setmask_mp(void)
|
|||
{
|
||||
int cpu;
|
||||
|
||||
preempt_disable();
|
||||
for_each_online_cpu(cpu)
|
||||
/* Enable all cpus with a declared buffer. */
|
||||
if (cpu_isset(cpu, iucv_buffer_cpumask) &&
|
||||
!cpu_isset(cpu, iucv_irq_cpumask))
|
||||
smp_call_function_on(iucv_allow_cpu, NULL, 0, 1, cpu);
|
||||
preempt_enable();
|
||||
}
|
||||
|
||||
/**
|
||||
* iucv_setmask_up
|
||||
*
|
||||
* Allow iucv interrupts on a single cpus.
|
||||
* Allow iucv interrupts on a single cpu.
|
||||
*/
|
||||
static void iucv_setmask_up(void)
|
||||
{
|
||||
|
|
@ -493,8 +518,10 @@ static int iucv_enable(void)
|
|||
goto out;
|
||||
/* Declare per cpu buffers. */
|
||||
rc = -EIO;
|
||||
preempt_disable();
|
||||
for_each_online_cpu(cpu)
|
||||
smp_call_function_on(iucv_declare_cpu, NULL, 0, 1, cpu);
|
||||
preempt_enable();
|
||||
if (cpus_empty(iucv_buffer_cpumask))
|
||||
/* No cpu could declare an iucv buffer. */
|
||||
goto out_path;
|
||||
|
|
@ -584,48 +611,49 @@ static int iucv_sever_pathid(u16 pathid, u8 userdata[16])
|
|||
return iucv_call_b2f0(IUCV_SEVER, parm);
|
||||
}
|
||||
|
||||
#ifdef CONFIG_SMP
|
||||
/**
|
||||
* __iucv_cleanup_pathid
|
||||
* __iucv_cleanup_queue
|
||||
* @dummy: unused dummy argument
|
||||
*
|
||||
* Nop function called via smp_call_function to force work items from
|
||||
* pending external iucv interrupts to the work queue.
|
||||
*/
|
||||
static void __iucv_cleanup_pathid(void *dummy)
|
||||
static void __iucv_cleanup_queue(void *dummy)
|
||||
{
|
||||
}
|
||||
#endif
|
||||
|
||||
/**
|
||||
* iucv_cleanup_pathid
|
||||
* @pathid: 16 bit pathid
|
||||
* iucv_cleanup_queue
|
||||
*
|
||||
* Function called after a path has been severed to find all remaining
|
||||
* work items for the now stale pathid. The caller needs to hold the
|
||||
* iucv_table_lock.
|
||||
*/
|
||||
static void iucv_cleanup_pathid(u16 pathid)
|
||||
static void iucv_cleanup_queue(void)
|
||||
{
|
||||
struct iucv_work *p, *n;
|
||||
struct iucv_irq_list *p, *n;
|
||||
|
||||
/*
|
||||
* Path is severed, the pathid can be reused immediatly on
|
||||
* a iucv connect or a connection pending interrupt.
|
||||
* iucv_path_connect and connection pending interrupt will
|
||||
* wait until the iucv_table_lock is released before the
|
||||
* recycled pathid enters the system.
|
||||
* Force remaining interrupts to the work queue, then
|
||||
* scan the work queue for items of this path.
|
||||
* When a path is severed, the pathid can be reused immediatly
|
||||
* on a iucv connect or a connection pending interrupt. Remove
|
||||
* all entries from the task queue that refer to a stale pathid
|
||||
* (iucv_path_table[ix] == NULL). Only then do the iucv connect
|
||||
* or deliver the connection pending interrupt. To get all the
|
||||
* pending interrupts force them to the work queue by calling
|
||||
* an empty function on all cpus.
|
||||
*/
|
||||
smp_call_function(__iucv_cleanup_pathid, NULL, 0, 1);
|
||||
spin_lock_irq(&iucv_work_lock);
|
||||
list_for_each_entry_safe(p, n, &iucv_work_queue, list) {
|
||||
/* Remove work items for pathid except connection pending */
|
||||
if (p->data.ippathid == pathid && p->data.iptype != 0x01) {
|
||||
smp_call_function(__iucv_cleanup_queue, NULL, 0, 1);
|
||||
spin_lock_irq(&iucv_queue_lock);
|
||||
list_for_each_entry_safe(p, n, &iucv_task_queue, list) {
|
||||
/* Remove stale work items from the task queue. */
|
||||
if (iucv_path_table[p->data.ippathid] == NULL) {
|
||||
list_del(&p->list);
|
||||
kfree(p);
|
||||
}
|
||||
}
|
||||
spin_unlock_irq(&iucv_work_lock);
|
||||
spin_unlock_irq(&iucv_queue_lock);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
@ -684,7 +712,6 @@ void iucv_unregister(struct iucv_handler *handler, int smp)
|
|||
iucv_sever_pathid(p->pathid, NULL);
|
||||
iucv_path_table[p->pathid] = NULL;
|
||||
list_del(&p->list);
|
||||
iucv_cleanup_pathid(p->pathid);
|
||||
iucv_path_free(p);
|
||||
}
|
||||
spin_unlock_bh(&iucv_table_lock);
|
||||
|
|
@ -757,9 +784,9 @@ int iucv_path_connect(struct iucv_path *path, struct iucv_handler *handler,
|
|||
union iucv_param *parm;
|
||||
int rc;
|
||||
|
||||
preempt_disable();
|
||||
if (iucv_tasklet_cpu != smp_processor_id())
|
||||
spin_lock_bh(&iucv_table_lock);
|
||||
BUG_ON(in_atomic());
|
||||
spin_lock_bh(&iucv_table_lock);
|
||||
iucv_cleanup_queue();
|
||||
parm = percpu_ptr(iucv_param, smp_processor_id());
|
||||
memset(parm, 0, sizeof(union iucv_param));
|
||||
parm->ctrl.ipmsglim = path->msglim;
|
||||
|
|
@ -794,9 +821,7 @@ int iucv_path_connect(struct iucv_path *path, struct iucv_handler *handler,
|
|||
rc = -EIO;
|
||||
}
|
||||
}
|
||||
if (iucv_tasklet_cpu != smp_processor_id())
|
||||
spin_unlock_bh(&iucv_table_lock);
|
||||
preempt_enable();
|
||||
spin_unlock_bh(&iucv_table_lock);
|
||||
return rc;
|
||||
}
|
||||
|
||||
|
|
@ -867,15 +892,14 @@ int iucv_path_sever(struct iucv_path *path, u8 userdata[16])
|
|||
|
||||
|
||||
preempt_disable();
|
||||
if (iucv_tasklet_cpu != smp_processor_id())
|
||||
if (iucv_active_cpu != smp_processor_id())
|
||||
spin_lock_bh(&iucv_table_lock);
|
||||
rc = iucv_sever_pathid(path->pathid, userdata);
|
||||
if (!rc) {
|
||||
iucv_path_table[path->pathid] = NULL;
|
||||
list_del_init(&path->list);
|
||||
iucv_cleanup_pathid(path->pathid);
|
||||
}
|
||||
if (iucv_tasklet_cpu != smp_processor_id())
|
||||
if (iucv_active_cpu != smp_processor_id())
|
||||
spin_unlock_bh(&iucv_table_lock);
|
||||
preempt_enable();
|
||||
return rc;
|
||||
|
|
@ -1244,8 +1268,7 @@ static void iucv_path_complete(struct iucv_irq_data *data)
|
|||
struct iucv_path_complete *ipc = (void *) data;
|
||||
struct iucv_path *path = iucv_path_table[ipc->ippathid];
|
||||
|
||||
BUG_ON(!path || !path->handler);
|
||||
if (path->handler->path_complete)
|
||||
if (path && path->handler && path->handler->path_complete)
|
||||
path->handler->path_complete(path, ipc->ipuser);
|
||||
}
|
||||
|
||||
|
|
@ -1273,14 +1296,14 @@ static void iucv_path_severed(struct iucv_irq_data *data)
|
|||
struct iucv_path_severed *ips = (void *) data;
|
||||
struct iucv_path *path = iucv_path_table[ips->ippathid];
|
||||
|
||||
BUG_ON(!path || !path->handler);
|
||||
if (!path || !path->handler) /* Already severed */
|
||||
return;
|
||||
if (path->handler->path_severed)
|
||||
path->handler->path_severed(path, ips->ipuser);
|
||||
else {
|
||||
iucv_sever_pathid(path->pathid, NULL);
|
||||
iucv_path_table[path->pathid] = NULL;
|
||||
list_del_init(&path->list);
|
||||
iucv_cleanup_pathid(path->pathid);
|
||||
iucv_path_free(path);
|
||||
}
|
||||
}
|
||||
|
|
@ -1309,8 +1332,7 @@ static void iucv_path_quiesced(struct iucv_irq_data *data)
|
|||
struct iucv_path_quiesced *ipq = (void *) data;
|
||||
struct iucv_path *path = iucv_path_table[ipq->ippathid];
|
||||
|
||||
BUG_ON(!path || !path->handler);
|
||||
if (path->handler->path_quiesced)
|
||||
if (path && path->handler && path->handler->path_quiesced)
|
||||
path->handler->path_quiesced(path, ipq->ipuser);
|
||||
}
|
||||
|
||||
|
|
@ -1338,8 +1360,7 @@ static void iucv_path_resumed(struct iucv_irq_data *data)
|
|||
struct iucv_path_resumed *ipr = (void *) data;
|
||||
struct iucv_path *path = iucv_path_table[ipr->ippathid];
|
||||
|
||||
BUG_ON(!path || !path->handler);
|
||||
if (path->handler->path_resumed)
|
||||
if (path && path->handler && path->handler->path_resumed)
|
||||
path->handler->path_resumed(path, ipr->ipuser);
|
||||
}
|
||||
|
||||
|
|
@ -1371,8 +1392,7 @@ static void iucv_message_complete(struct iucv_irq_data *data)
|
|||
struct iucv_path *path = iucv_path_table[imc->ippathid];
|
||||
struct iucv_message msg;
|
||||
|
||||
BUG_ON(!path || !path->handler);
|
||||
if (path->handler->message_complete) {
|
||||
if (path && path->handler && path->handler->message_complete) {
|
||||
msg.flags = imc->ipflags1;
|
||||
msg.id = imc->ipmsgid;
|
||||
msg.audit = imc->ipaudit;
|
||||
|
|
@ -1417,8 +1437,7 @@ static void iucv_message_pending(struct iucv_irq_data *data)
|
|||
struct iucv_path *path = iucv_path_table[imp->ippathid];
|
||||
struct iucv_message msg;
|
||||
|
||||
BUG_ON(!path || !path->handler);
|
||||
if (path->handler->message_pending) {
|
||||
if (path && path->handler && path->handler->message_pending) {
|
||||
msg.flags = imp->ipflags1;
|
||||
msg.id = imp->ipmsgid;
|
||||
msg.class = imp->iptrgcls;
|
||||
|
|
@ -1433,17 +1452,16 @@ static void iucv_message_pending(struct iucv_irq_data *data)
|
|||
}
|
||||
|
||||
/**
|
||||
* iucv_tasklet_handler:
|
||||
* iucv_tasklet_fn:
|
||||
*
|
||||
* This tasklet loops over the queue of irq buffers created by
|
||||
* iucv_external_interrupt, calls the appropriate action handler
|
||||
* and then frees the buffer.
|
||||
*/
|
||||
static void iucv_tasklet_handler(unsigned long ignored)
|
||||
static void iucv_tasklet_fn(unsigned long ignored)
|
||||
{
|
||||
typedef void iucv_irq_fn(struct iucv_irq_data *);
|
||||
static iucv_irq_fn *irq_fn[] = {
|
||||
[0x01] = iucv_path_pending,
|
||||
[0x02] = iucv_path_complete,
|
||||
[0x03] = iucv_path_severed,
|
||||
[0x04] = iucv_path_quiesced,
|
||||
|
|
@ -1453,38 +1471,70 @@ static void iucv_tasklet_handler(unsigned long ignored)
|
|||
[0x08] = iucv_message_pending,
|
||||
[0x09] = iucv_message_pending,
|
||||
};
|
||||
struct iucv_work *p;
|
||||
struct list_head task_queue = LIST_HEAD_INIT(task_queue);
|
||||
struct iucv_irq_list *p, *n;
|
||||
|
||||
/* Serialize tasklet, iucv_path_sever and iucv_path_connect. */
|
||||
spin_lock(&iucv_table_lock);
|
||||
iucv_tasklet_cpu = smp_processor_id();
|
||||
iucv_active_cpu = smp_processor_id();
|
||||
|
||||
spin_lock_irq(&iucv_work_lock);
|
||||
while (!list_empty(&iucv_work_queue)) {
|
||||
p = list_entry(iucv_work_queue.next, struct iucv_work, list);
|
||||
spin_lock_irq(&iucv_queue_lock);
|
||||
list_splice_init(&iucv_task_queue, &task_queue);
|
||||
spin_unlock_irq(&iucv_queue_lock);
|
||||
|
||||
list_for_each_entry_safe(p, n, &task_queue, list) {
|
||||
list_del_init(&p->list);
|
||||
spin_unlock_irq(&iucv_work_lock);
|
||||
irq_fn[p->data.iptype](&p->data);
|
||||
kfree(p);
|
||||
spin_lock_irq(&iucv_work_lock);
|
||||
}
|
||||
spin_unlock_irq(&iucv_work_lock);
|
||||
|
||||
iucv_tasklet_cpu = -1;
|
||||
iucv_active_cpu = -1;
|
||||
spin_unlock(&iucv_table_lock);
|
||||
}
|
||||
|
||||
/**
|
||||
* iucv_work_fn:
|
||||
*
|
||||
* This work function loops over the queue of path pending irq blocks
|
||||
* created by iucv_external_interrupt, calls the appropriate action
|
||||
* handler and then frees the buffer.
|
||||
*/
|
||||
static void iucv_work_fn(struct work_struct *work)
|
||||
{
|
||||
typedef void iucv_irq_fn(struct iucv_irq_data *);
|
||||
struct list_head work_queue = LIST_HEAD_INIT(work_queue);
|
||||
struct iucv_irq_list *p, *n;
|
||||
|
||||
/* Serialize tasklet, iucv_path_sever and iucv_path_connect. */
|
||||
spin_lock_bh(&iucv_table_lock);
|
||||
iucv_active_cpu = smp_processor_id();
|
||||
|
||||
spin_lock_irq(&iucv_queue_lock);
|
||||
list_splice_init(&iucv_work_queue, &work_queue);
|
||||
spin_unlock_irq(&iucv_queue_lock);
|
||||
|
||||
iucv_cleanup_queue();
|
||||
list_for_each_entry_safe(p, n, &work_queue, list) {
|
||||
list_del_init(&p->list);
|
||||
iucv_path_pending(&p->data);
|
||||
kfree(p);
|
||||
}
|
||||
|
||||
iucv_active_cpu = -1;
|
||||
spin_unlock_bh(&iucv_table_lock);
|
||||
}
|
||||
|
||||
/**
|
||||
* iucv_external_interrupt
|
||||
* @code: irq code
|
||||
*
|
||||
* Handles external interrupts coming in from CP.
|
||||
* Places the interrupt buffer on a queue and schedules iucv_tasklet_handler().
|
||||
* Places the interrupt buffer on a queue and schedules iucv_tasklet_fn().
|
||||
*/
|
||||
static void iucv_external_interrupt(u16 code)
|
||||
{
|
||||
struct iucv_irq_data *p;
|
||||
struct iucv_work *work;
|
||||
struct iucv_irq_list *work;
|
||||
|
||||
p = percpu_ptr(iucv_irq_data, smp_processor_id());
|
||||
if (p->ippathid >= iucv_max_pathid) {
|
||||
|
|
@ -1498,16 +1548,23 @@ static void iucv_external_interrupt(u16 code)
|
|||
printk(KERN_ERR "iucv_do_int: unknown iucv interrupt\n");
|
||||
return;
|
||||
}
|
||||
work = kmalloc(sizeof(struct iucv_work), GFP_ATOMIC);
|
||||
work = kmalloc(sizeof(struct iucv_irq_list), GFP_ATOMIC);
|
||||
if (!work) {
|
||||
printk(KERN_WARNING "iucv_external_interrupt: out of memory\n");
|
||||
return;
|
||||
}
|
||||
memcpy(&work->data, p, sizeof(work->data));
|
||||
spin_lock(&iucv_work_lock);
|
||||
list_add_tail(&work->list, &iucv_work_queue);
|
||||
spin_unlock(&iucv_work_lock);
|
||||
tasklet_schedule(&iucv_tasklet);
|
||||
spin_lock(&iucv_queue_lock);
|
||||
if (p->iptype == 0x01) {
|
||||
/* Path pending interrupt. */
|
||||
list_add_tail(&work->list, &iucv_work_queue);
|
||||
schedule_work(&iucv_work);
|
||||
} else {
|
||||
/* The other interrupts. */
|
||||
list_add_tail(&work->list, &iucv_task_queue);
|
||||
tasklet_schedule(&iucv_tasklet);
|
||||
}
|
||||
spin_unlock(&iucv_queue_lock);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
@ -1577,12 +1634,14 @@ out:
|
|||
*/
|
||||
static void iucv_exit(void)
|
||||
{
|
||||
struct iucv_work *p, *n;
|
||||
struct iucv_irq_list *p, *n;
|
||||
|
||||
spin_lock_irq(&iucv_work_lock);
|
||||
spin_lock_irq(&iucv_queue_lock);
|
||||
list_for_each_entry_safe(p, n, &iucv_task_queue, list)
|
||||
kfree(p);
|
||||
list_for_each_entry_safe(p, n, &iucv_work_queue, list)
|
||||
kfree(p);
|
||||
spin_unlock_irq(&iucv_work_lock);
|
||||
spin_unlock_irq(&iucv_queue_lock);
|
||||
unregister_hotcpu_notifier(&iucv_cpu_notifier);
|
||||
percpu_free(iucv_param);
|
||||
percpu_free(iucv_irq_data);
|
||||
|
|
|
|||
Загрузка…
Ссылка в новой задаче