xen: bug fixes for 4.2-rc5

- Don't lose interrupts when offlining CPUs.
 - Fix gntdev oops during unmap.
 - Drop the balloon lock occasionally to allow domain create/destroy.
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Merge tag 'for-linus-4.2-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen bug fixes from David Vrabel:

 - don't lose interrupts when offlining CPUs

 - fix gntdev oops during unmap

 - drop the balloon lock occasionally to allow domain create/destroy

* tag 'for-linus-4.2-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/events/fifo: Handle linked events when closing a port
  xen: release lock occasionally during ballooning
  xen/gntdevt: Fix race condition in gntdev_release()
This commit is contained in:
Linus Torvalds 2015-08-04 08:49:08 -07:00
commit 1ddc6dd855
5 changed files with 62 additions and 17 deletions

View File

@ -472,7 +472,7 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
}
/*
* We avoid multiple worker processes conflicting via the balloon mutex.
* As this is a work item it is guaranteed to run as a single instance only.
* We may of course race updates of the target counts (which are protected
* by the balloon lock), or with changes to the Xen hard limit, but we will
* recover from these in time.
@ -482,9 +482,10 @@ static void balloon_process(struct work_struct *work)
enum bp_state state = BP_DONE;
long credit;
mutex_lock(&balloon_mutex);
do {
mutex_lock(&balloon_mutex);
credit = current_credit();
if (credit > 0) {
@ -499,17 +500,15 @@ static void balloon_process(struct work_struct *work)
state = update_schedule(state);
#ifndef CONFIG_PREEMPT
if (need_resched())
schedule();
#endif
mutex_unlock(&balloon_mutex);
cond_resched();
} while (credit && state == BP_DONE);
/* Schedule more work if there is some still to be done. */
if (state == BP_EAGAIN)
schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ);
mutex_unlock(&balloon_mutex);
}
/* Resets the Xen limit, sets new target, and kicks off processing. */

View File

@ -452,10 +452,12 @@ static void xen_free_irq(unsigned irq)
irq_free_desc(irq);
}
static void xen_evtchn_close(unsigned int port)
static void xen_evtchn_close(unsigned int port, unsigned int cpu)
{
struct evtchn_close close;
xen_evtchn_op_close(port, cpu);
close.port = port;
if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
BUG();
@ -544,7 +546,7 @@ out:
err:
pr_err("irq%d: Failed to set port to irq mapping (%d)\n", irq, rc);
xen_evtchn_close(evtchn);
xen_evtchn_close(evtchn, NR_CPUS);
return 0;
}
@ -565,7 +567,7 @@ static void shutdown_pirq(struct irq_data *data)
return;
mask_evtchn(evtchn);
xen_evtchn_close(evtchn);
xen_evtchn_close(evtchn, cpu_from_evtchn(evtchn));
xen_irq_info_cleanup(info);
}
@ -609,7 +611,7 @@ static void __unbind_from_irq(unsigned int irq)
if (VALID_EVTCHN(evtchn)) {
unsigned int cpu = cpu_from_irq(irq);
xen_evtchn_close(evtchn);
xen_evtchn_close(evtchn, cpu);
switch (type_from_irq(irq)) {
case IRQT_VIRQ:

View File

@ -255,6 +255,12 @@ static void evtchn_fifo_unmask(unsigned port)
}
}
static bool evtchn_fifo_is_linked(unsigned port)
{
event_word_t *word = event_word_from_port(port);
return sync_test_bit(EVTCHN_FIFO_BIT(LINKED, word), BM(word));
}
static uint32_t clear_linked(volatile event_word_t *word)
{
event_word_t new, old, w;
@ -281,7 +287,8 @@ static void handle_irq_for_port(unsigned port)
static void consume_one_event(unsigned cpu,
struct evtchn_fifo_control_block *control_block,
unsigned priority, unsigned long *ready)
unsigned priority, unsigned long *ready,
bool drop)
{
struct evtchn_fifo_queue *q = &per_cpu(cpu_queue, cpu);
uint32_t head;
@ -313,13 +320,15 @@ static void consume_one_event(unsigned cpu,
if (head == 0)
clear_bit(priority, ready);
if (evtchn_fifo_is_pending(port) && !evtchn_fifo_is_masked(port))
handle_irq_for_port(port);
if (evtchn_fifo_is_pending(port) && !evtchn_fifo_is_masked(port)) {
if (likely(!drop))
handle_irq_for_port(port);
}
q->head[priority] = head;
}
static void evtchn_fifo_handle_events(unsigned cpu)
static void __evtchn_fifo_handle_events(unsigned cpu, bool drop)
{
struct evtchn_fifo_control_block *control_block;
unsigned long ready;
@ -331,11 +340,16 @@ static void evtchn_fifo_handle_events(unsigned cpu)
while (ready) {
q = find_first_bit(&ready, EVTCHN_FIFO_MAX_QUEUES);
consume_one_event(cpu, control_block, q, &ready);
consume_one_event(cpu, control_block, q, &ready, drop);
ready |= xchg(&control_block->ready, 0);
}
}
static void evtchn_fifo_handle_events(unsigned cpu)
{
__evtchn_fifo_handle_events(cpu, false);
}
static void evtchn_fifo_resume(void)
{
unsigned cpu;
@ -371,6 +385,26 @@ static void evtchn_fifo_resume(void)
event_array_pages = 0;
}
static void evtchn_fifo_close(unsigned port, unsigned int cpu)
{
if (cpu == NR_CPUS)
return;
get_online_cpus();
if (cpu_online(cpu)) {
if (WARN_ON(irqs_disabled()))
goto out;
while (evtchn_fifo_is_linked(port))
cpu_relax();
} else {
__evtchn_fifo_handle_events(cpu, true);
}
out:
put_online_cpus();
}
static const struct evtchn_ops evtchn_ops_fifo = {
.max_channels = evtchn_fifo_max_channels,
.nr_channels = evtchn_fifo_nr_channels,
@ -384,6 +418,7 @@ static const struct evtchn_ops evtchn_ops_fifo = {
.unmask = evtchn_fifo_unmask,
.handle_events = evtchn_fifo_handle_events,
.resume = evtchn_fifo_resume,
.close = evtchn_fifo_close,
};
static int evtchn_fifo_alloc_control_block(unsigned cpu)

View File

@ -68,6 +68,7 @@ struct evtchn_ops {
bool (*test_and_set_mask)(unsigned port);
void (*mask)(unsigned port);
void (*unmask)(unsigned port);
void (*close)(unsigned port, unsigned cpu);
void (*handle_events)(unsigned cpu);
void (*resume)(void);
@ -145,6 +146,12 @@ static inline void xen_evtchn_resume(void)
evtchn_ops->resume();
}
static inline void xen_evtchn_op_close(unsigned port, unsigned cpu)
{
if (evtchn_ops->close)
return evtchn_ops->close(port, cpu);
}
void xen_evtchn_2l_init(void);
int xen_evtchn_fifo_init(void);

View File

@ -568,12 +568,14 @@ static int gntdev_release(struct inode *inode, struct file *flip)
pr_debug("priv %p\n", priv);
mutex_lock(&priv->lock);
while (!list_empty(&priv->maps)) {
map = list_entry(priv->maps.next, struct grant_map, next);
list_del(&map->next);
gntdev_put_map(NULL /* already removed */, map);
}
WARN_ON(!list_empty(&priv->freeable_maps));
mutex_unlock(&priv->lock);
if (use_ptemod)
mmu_notifier_unregister(&priv->mn, priv->mm);