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authorDavid S. Miller <davem@davemloft.net>2012-09-15 11:43:53 -0400
committerDavid S. Miller <davem@davemloft.net>2012-09-15 11:43:53 -0400
commitb48b63a1f6e26b0dec2c9f1690396ed4bcb66903 (patch)
tree8d9ad227c3a7d35cd78d40ecaf9bf59375dbd21a /kernel
parent7f2e6a5d8608d0353b017a0fe15502307593734e (diff)
parent3f0c3c8fe30c725c1264fb6db8cc4b69db3a658a (diff)
downloadop-kernel-dev-b48b63a1f6e26b0dec2c9f1690396ed4bcb66903.zip
op-kernel-dev-b48b63a1f6e26b0dec2c9f1690396ed4bcb66903.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts: net/netfilter/nfnetlink_log.c net/netfilter/xt_LOG.c Rather easy conflict resolution, the 'net' tree had bug fixes to make sure we checked if a socket is a time-wait one or not and elide the logging code if so. Whereas on the 'net-next' side we are calculating the UID and GID from the creds using different interfaces due to the user namespace changes from Eric Biederman. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c64
-rw-r--r--kernel/events/hw_breakpoint.c11
-rw-r--r--kernel/fork.c4
-rw-r--r--kernel/sched/core.c34
-rw-r--r--kernel/sched/fair.c9
-rw-r--r--kernel/sched/rt.c1
-rw-r--r--kernel/sched/sched.h1
-rw-r--r--kernel/time/tick-sched.c1
-rw-r--r--kernel/time/timekeeping.c39
-rw-r--r--kernel/trace/trace_syscalls.c4
-rw-r--r--kernel/workqueue.c110
11 files changed, 189 insertions, 89 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index b7935fc..7fee567 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1253,7 +1253,7 @@ retry:
/*
* Cross CPU call to disable a performance event
*/
-static int __perf_event_disable(void *info)
+int __perf_event_disable(void *info)
{
struct perf_event *event = info;
struct perf_event_context *ctx = event->ctx;
@@ -2935,12 +2935,12 @@ EXPORT_SYMBOL_GPL(perf_event_release_kernel);
/*
* Called when the last reference to the file is gone.
*/
-static int perf_release(struct inode *inode, struct file *file)
+static void put_event(struct perf_event *event)
{
- struct perf_event *event = file->private_data;
struct task_struct *owner;
- file->private_data = NULL;
+ if (!atomic_long_dec_and_test(&event->refcount))
+ return;
rcu_read_lock();
owner = ACCESS_ONCE(event->owner);
@@ -2975,7 +2975,13 @@ static int perf_release(struct inode *inode, struct file *file)
put_task_struct(owner);
}
- return perf_event_release_kernel(event);
+ perf_event_release_kernel(event);
+}
+
+static int perf_release(struct inode *inode, struct file *file)
+{
+ put_event(file->private_data);
+ return 0;
}
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
@@ -3227,7 +3233,7 @@ unlock:
static const struct file_operations perf_fops;
-static struct perf_event *perf_fget_light(int fd, int *fput_needed)
+static struct file *perf_fget_light(int fd, int *fput_needed)
{
struct file *file;
@@ -3241,7 +3247,7 @@ static struct perf_event *perf_fget_light(int fd, int *fput_needed)
return ERR_PTR(-EBADF);
}
- return file->private_data;
+ return file;
}
static int perf_event_set_output(struct perf_event *event,
@@ -3273,19 +3279,21 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case PERF_EVENT_IOC_SET_OUTPUT:
{
+ struct file *output_file = NULL;
struct perf_event *output_event = NULL;
int fput_needed = 0;
int ret;
if (arg != -1) {
- output_event = perf_fget_light(arg, &fput_needed);
- if (IS_ERR(output_event))
- return PTR_ERR(output_event);
+ output_file = perf_fget_light(arg, &fput_needed);
+ if (IS_ERR(output_file))
+ return PTR_ERR(output_file);
+ output_event = output_file->private_data;
}
ret = perf_event_set_output(event, output_event);
if (output_event)
- fput_light(output_event->filp, fput_needed);
+ fput_light(output_file, fput_needed);
return ret;
}
@@ -5950,6 +5958,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
mutex_init(&event->mmap_mutex);
+ atomic_long_set(&event->refcount, 1);
event->cpu = cpu;
event->attr = *attr;
event->group_leader = group_leader;
@@ -6260,12 +6269,12 @@ SYSCALL_DEFINE5(perf_event_open,
return event_fd;
if (group_fd != -1) {
- group_leader = perf_fget_light(group_fd, &fput_needed);
- if (IS_ERR(group_leader)) {
- err = PTR_ERR(group_leader);
+ group_file = perf_fget_light(group_fd, &fput_needed);
+ if (IS_ERR(group_file)) {
+ err = PTR_ERR(group_file);
goto err_fd;
}
- group_file = group_leader->filp;
+ group_leader = group_file->private_data;
if (flags & PERF_FLAG_FD_OUTPUT)
output_event = group_leader;
if (flags & PERF_FLAG_FD_NO_GROUP)
@@ -6402,7 +6411,6 @@ SYSCALL_DEFINE5(perf_event_open,
put_ctx(gctx);
}
- event->filp = event_file;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
@@ -6496,7 +6504,6 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
goto err_free;
}
- event->filp = NULL;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
perf_install_in_context(ctx, event, cpu);
@@ -6578,7 +6585,7 @@ static void sync_child_event(struct perf_event *child_event,
* Release the parent event, if this was the last
* reference to it.
*/
- fput(parent_event->filp);
+ put_event(parent_event);
}
static void
@@ -6654,9 +6661,8 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
*
* __perf_event_exit_task()
* sync_child_event()
- * fput(parent_event->filp)
- * perf_release()
- * mutex_lock(&ctx->mutex)
+ * put_event()
+ * mutex_lock(&ctx->mutex)
*
* But since its the parent context it won't be the same instance.
*/
@@ -6724,7 +6730,7 @@ static void perf_free_event(struct perf_event *event,
list_del_init(&event->child_list);
mutex_unlock(&parent->child_mutex);
- fput(parent->filp);
+ put_event(parent);
perf_group_detach(event);
list_del_event(event, ctx);
@@ -6804,6 +6810,12 @@ inherit_event(struct perf_event *parent_event,
NULL, NULL);
if (IS_ERR(child_event))
return child_event;
+
+ if (!atomic_long_inc_not_zero(&parent_event->refcount)) {
+ free_event(child_event);
+ return NULL;
+ }
+
get_ctx(child_ctx);
/*
@@ -6845,14 +6857,6 @@ inherit_event(struct perf_event *parent_event,
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
/*
- * Get a reference to the parent filp - we will fput it
- * when the child event exits. This is safe to do because
- * we are in the parent and we know that the filp still
- * exists and has a nonzero count:
- */
- atomic_long_inc(&parent_event->filp->f_count);
-
- /*
* Link this into the parent event's child list
*/
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index bb38c4d..9a7b487 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -453,7 +453,16 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att
int old_type = bp->attr.bp_type;
int err = 0;
- perf_event_disable(bp);
+ /*
+ * modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it
+ * will not be possible to raise IPIs that invoke __perf_event_disable.
+ * So call the function directly after making sure we are targeting the
+ * current task.
+ */
+ if (irqs_disabled() && bp->ctx && bp->ctx->task == current)
+ __perf_event_disable(bp);
+ else
+ perf_event_disable(bp);
bp->attr.bp_addr = attr->bp_addr;
bp->attr.bp_type = attr->bp_type;
diff --git a/kernel/fork.c b/kernel/fork.c
index 3bd2280..2c8857e 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -455,8 +455,8 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
if (retval)
goto out;
- if (file && uprobe_mmap(tmp))
- goto out;
+ if (file)
+ uprobe_mmap(tmp);
}
/* a new mm has just been created */
arch_dup_mmap(oldmm, mm);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fbf1fd0..a4ea245 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5304,27 +5304,17 @@ void idle_task_exit(void)
}
/*
- * While a dead CPU has no uninterruptible tasks queued at this point,
- * it might still have a nonzero ->nr_uninterruptible counter, because
- * for performance reasons the counter is not stricly tracking tasks to
- * their home CPUs. So we just add the counter to another CPU's counter,
- * to keep the global sum constant after CPU-down:
- */
-static void migrate_nr_uninterruptible(struct rq *rq_src)
-{
- struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
-
- rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
- rq_src->nr_uninterruptible = 0;
-}
-
-/*
- * remove the tasks which were accounted by rq from calc_load_tasks.
+ * Since this CPU is going 'away' for a while, fold any nr_active delta
+ * we might have. Assumes we're called after migrate_tasks() so that the
+ * nr_active count is stable.
+ *
+ * Also see the comment "Global load-average calculations".
*/
-static void calc_global_load_remove(struct rq *rq)
+static void calc_load_migrate(struct rq *rq)
{
- atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
- rq->calc_load_active = 0;
+ long delta = calc_load_fold_active(rq);
+ if (delta)
+ atomic_long_add(delta, &calc_load_tasks);
}
/*
@@ -5352,9 +5342,6 @@ static void migrate_tasks(unsigned int dead_cpu)
*/
rq->stop = NULL;
- /* Ensure any throttled groups are reachable by pick_next_task */
- unthrottle_offline_cfs_rqs(rq);
-
for ( ; ; ) {
/*
* There's this thread running, bail when that's the only
@@ -5618,8 +5605,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
BUG_ON(rq->nr_running != 1); /* the migration thread */
raw_spin_unlock_irqrestore(&rq->lock, flags);
- migrate_nr_uninterruptible(rq);
- calc_global_load_remove(rq);
+ calc_load_migrate(rq);
break;
#endif
}
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c219bf8..42d9df6 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2052,7 +2052,7 @@ static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
hrtimer_cancel(&cfs_b->slack_timer);
}
-void unthrottle_offline_cfs_rqs(struct rq *rq)
+static void unthrottle_offline_cfs_rqs(struct rq *rq)
{
struct cfs_rq *cfs_rq;
@@ -2106,7 +2106,7 @@ static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
return NULL;
}
static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
-void unthrottle_offline_cfs_rqs(struct rq *rq) {}
+static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {}
#endif /* CONFIG_CFS_BANDWIDTH */
@@ -3658,7 +3658,6 @@ fix_small_capacity(struct sched_domain *sd, struct sched_group *group)
* @group: sched_group whose statistics are to be updated.
* @load_idx: Load index of sched_domain of this_cpu for load calc.
* @local_group: Does group contain this_cpu.
- * @cpus: Set of cpus considered for load balancing.
* @balance: Should we balance.
* @sgs: variable to hold the statistics for this group.
*/
@@ -3805,7 +3804,6 @@ static bool update_sd_pick_busiest(struct lb_env *env,
/**
* update_sd_lb_stats - Update sched_domain's statistics for load balancing.
* @env: The load balancing environment.
- * @cpus: Set of cpus considered for load balancing.
* @balance: Should we balance.
* @sds: variable to hold the statistics for this sched_domain.
*/
@@ -4956,6 +4954,9 @@ static void rq_online_fair(struct rq *rq)
static void rq_offline_fair(struct rq *rq)
{
update_sysctl();
+
+ /* Ensure any throttled groups are reachable by pick_next_task */
+ unthrottle_offline_cfs_rqs(rq);
}
#endif /* CONFIG_SMP */
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 944cb68..e0b7ba9 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -691,6 +691,7 @@ balanced:
* runtime - in which case borrowing doesn't make sense.
*/
rt_rq->rt_runtime = RUNTIME_INF;
+ rt_rq->rt_throttled = 0;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
raw_spin_unlock(&rt_b->rt_runtime_lock);
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index f6714d0..0848fa3 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1144,7 +1144,6 @@ extern void print_rt_stats(struct seq_file *m, int cpu);
extern void init_cfs_rq(struct cfs_rq *cfs_rq);
extern void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq);
-extern void unthrottle_offline_cfs_rqs(struct rq *rq);
extern void account_cfs_bandwidth_used(int enabled, int was_enabled);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 024540f..3a9e5d5 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -573,6 +573,7 @@ static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
tick_do_update_jiffies64(now);
update_cpu_load_nohz();
+ calc_load_exit_idle();
touch_softlockup_watchdog();
/*
* Cancel the scheduled timer and restore the tick
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index e16af19..34e5eac 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -115,6 +115,7 @@ static void tk_xtime_add(struct timekeeper *tk, const struct timespec *ts)
{
tk->xtime_sec += ts->tv_sec;
tk->xtime_nsec += (u64)ts->tv_nsec << tk->shift;
+ tk_normalize_xtime(tk);
}
static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec wtm)
@@ -276,7 +277,7 @@ static void timekeeping_forward_now(struct timekeeper *tk)
tk->xtime_nsec += cycle_delta * tk->mult;
/* If arch requires, add in gettimeoffset() */
- tk->xtime_nsec += arch_gettimeoffset() << tk->shift;
+ tk->xtime_nsec += (u64)arch_gettimeoffset() << tk->shift;
tk_normalize_xtime(tk);
@@ -427,7 +428,7 @@ int do_settimeofday(const struct timespec *tv)
struct timespec ts_delta, xt;
unsigned long flags;
- if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
+ if (!timespec_valid_strict(tv))
return -EINVAL;
write_seqlock_irqsave(&tk->lock, flags);
@@ -463,6 +464,8 @@ int timekeeping_inject_offset(struct timespec *ts)
{
struct timekeeper *tk = &timekeeper;
unsigned long flags;
+ struct timespec tmp;
+ int ret = 0;
if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
@@ -471,10 +474,17 @@ int timekeeping_inject_offset(struct timespec *ts)
timekeeping_forward_now(tk);
+ /* Make sure the proposed value is valid */
+ tmp = timespec_add(tk_xtime(tk), *ts);
+ if (!timespec_valid_strict(&tmp)) {
+ ret = -EINVAL;
+ goto error;
+ }
tk_xtime_add(tk, ts);
tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, *ts));
+error: /* even if we error out, we forwarded the time, so call update */
timekeeping_update(tk, true);
write_sequnlock_irqrestore(&tk->lock, flags);
@@ -482,7 +492,7 @@ int timekeeping_inject_offset(struct timespec *ts)
/* signal hrtimers about time change */
clock_was_set();
- return 0;
+ return ret;
}
EXPORT_SYMBOL(timekeeping_inject_offset);
@@ -649,7 +659,20 @@ void __init timekeeping_init(void)
struct timespec now, boot, tmp;
read_persistent_clock(&now);
+ if (!timespec_valid_strict(&now)) {
+ pr_warn("WARNING: Persistent clock returned invalid value!\n"
+ " Check your CMOS/BIOS settings.\n");
+ now.tv_sec = 0;
+ now.tv_nsec = 0;
+ }
+
read_boot_clock(&boot);
+ if (!timespec_valid_strict(&boot)) {
+ pr_warn("WARNING: Boot clock returned invalid value!\n"
+ " Check your CMOS/BIOS settings.\n");
+ boot.tv_sec = 0;
+ boot.tv_nsec = 0;
+ }
seqlock_init(&tk->lock);
@@ -690,7 +713,7 @@ static struct timespec timekeeping_suspend_time;
static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
struct timespec *delta)
{
- if (!timespec_valid(delta)) {
+ if (!timespec_valid_strict(delta)) {
printk(KERN_WARNING "__timekeeping_inject_sleeptime: Invalid "
"sleep delta value!\n");
return;
@@ -1129,6 +1152,10 @@ static void update_wall_time(void)
offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
#endif
+ /* Check if there's really nothing to do */
+ if (offset < tk->cycle_interval)
+ goto out;
+
/*
* With NO_HZ we may have to accumulate many cycle_intervals
* (think "ticks") worth of time at once. To do this efficiently,
@@ -1161,9 +1188,9 @@ static void update_wall_time(void)
* the vsyscall implementations are converted to use xtime_nsec
* (shifted nanoseconds), this can be killed.
*/
- remainder = tk->xtime_nsec & ((1 << tk->shift) - 1);
+ remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1);
tk->xtime_nsec -= remainder;
- tk->xtime_nsec += 1 << tk->shift;
+ tk->xtime_nsec += 1ULL << tk->shift;
tk->ntp_error += remainder << tk->ntp_error_shift;
/*
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 60e4d78..6b245f64 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -506,6 +506,8 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
int size;
syscall_nr = syscall_get_nr(current, regs);
+ if (syscall_nr < 0)
+ return;
if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
return;
@@ -580,6 +582,8 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
int size;
syscall_nr = syscall_get_nr(current, regs);
+ if (syscall_nr < 0)
+ return;
if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
return;
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 692d976..1e1373b 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -66,6 +66,7 @@ enum {
/* pool flags */
POOL_MANAGE_WORKERS = 1 << 0, /* need to manage workers */
+ POOL_MANAGING_WORKERS = 1 << 1, /* managing workers */
/* worker flags */
WORKER_STARTED = 1 << 0, /* started */
@@ -652,7 +653,7 @@ static bool need_to_manage_workers(struct worker_pool *pool)
/* Do we have too many workers and should some go away? */
static bool too_many_workers(struct worker_pool *pool)
{
- bool managing = mutex_is_locked(&pool->manager_mutex);
+ bool managing = pool->flags & POOL_MANAGING_WORKERS;
int nr_idle = pool->nr_idle + managing; /* manager is considered idle */
int nr_busy = pool->nr_workers - nr_idle;
@@ -1326,6 +1327,15 @@ static void idle_worker_rebind(struct worker *worker)
/* we did our part, wait for rebind_workers() to finish up */
wait_event(gcwq->rebind_hold, !(worker->flags & WORKER_REBIND));
+
+ /*
+ * rebind_workers() shouldn't finish until all workers passed the
+ * above WORKER_REBIND wait. Tell it when done.
+ */
+ spin_lock_irq(&worker->pool->gcwq->lock);
+ if (!--worker->idle_rebind->cnt)
+ complete(&worker->idle_rebind->done);
+ spin_unlock_irq(&worker->pool->gcwq->lock);
}
/*
@@ -1396,12 +1406,15 @@ retry:
/* set REBIND and kick idle ones, we'll wait for these later */
for_each_worker_pool(pool, gcwq) {
list_for_each_entry(worker, &pool->idle_list, entry) {
+ unsigned long worker_flags = worker->flags;
+
if (worker->flags & WORKER_REBIND)
continue;
- /* morph UNBOUND to REBIND */
- worker->flags &= ~WORKER_UNBOUND;
- worker->flags |= WORKER_REBIND;
+ /* morph UNBOUND to REBIND atomically */
+ worker_flags &= ~WORKER_UNBOUND;
+ worker_flags |= WORKER_REBIND;
+ ACCESS_ONCE(worker->flags) = worker_flags;
idle_rebind.cnt++;
worker->idle_rebind = &idle_rebind;
@@ -1419,25 +1432,15 @@ retry:
goto retry;
}
- /*
- * All idle workers are rebound and waiting for %WORKER_REBIND to
- * be cleared inside idle_worker_rebind(). Clear and release.
- * Clearing %WORKER_REBIND from this foreign context is safe
- * because these workers are still guaranteed to be idle.
- */
- for_each_worker_pool(pool, gcwq)
- list_for_each_entry(worker, &pool->idle_list, entry)
- worker->flags &= ~WORKER_REBIND;
-
- wake_up_all(&gcwq->rebind_hold);
-
- /* rebind busy workers */
+ /* all idle workers are rebound, rebind busy workers */
for_each_busy_worker(worker, i, pos, gcwq) {
struct work_struct *rebind_work = &worker->rebind_work;
+ unsigned long worker_flags = worker->flags;
- /* morph UNBOUND to REBIND */
- worker->flags &= ~WORKER_UNBOUND;
- worker->flags |= WORKER_REBIND;
+ /* morph UNBOUND to REBIND atomically */
+ worker_flags &= ~WORKER_UNBOUND;
+ worker_flags |= WORKER_REBIND;
+ ACCESS_ONCE(worker->flags) = worker_flags;
if (test_and_set_bit(WORK_STRUCT_PENDING_BIT,
work_data_bits(rebind_work)))
@@ -1449,6 +1452,34 @@ retry:
worker->scheduled.next,
work_color_to_flags(WORK_NO_COLOR));
}
+
+ /*
+ * All idle workers are rebound and waiting for %WORKER_REBIND to
+ * be cleared inside idle_worker_rebind(). Clear and release.
+ * Clearing %WORKER_REBIND from this foreign context is safe
+ * because these workers are still guaranteed to be idle.
+ *
+ * We need to make sure all idle workers passed WORKER_REBIND wait
+ * in idle_worker_rebind() before returning; otherwise, workers can
+ * get stuck at the wait if hotplug cycle repeats.
+ */
+ idle_rebind.cnt = 1;
+ INIT_COMPLETION(idle_rebind.done);
+
+ for_each_worker_pool(pool, gcwq) {
+ list_for_each_entry(worker, &pool->idle_list, entry) {
+ worker->flags &= ~WORKER_REBIND;
+ idle_rebind.cnt++;
+ }
+ }
+
+ wake_up_all(&gcwq->rebind_hold);
+
+ if (--idle_rebind.cnt) {
+ spin_unlock_irq(&gcwq->lock);
+ wait_for_completion(&idle_rebind.done);
+ spin_lock_irq(&gcwq->lock);
+ }
}
static struct worker *alloc_worker(void)
@@ -1794,9 +1825,45 @@ static bool manage_workers(struct worker *worker)
struct worker_pool *pool = worker->pool;
bool ret = false;
- if (!mutex_trylock(&pool->manager_mutex))
+ if (pool->flags & POOL_MANAGING_WORKERS)
return ret;
+ pool->flags |= POOL_MANAGING_WORKERS;
+
+ /*
+ * To simplify both worker management and CPU hotplug, hold off
+ * management while hotplug is in progress. CPU hotplug path can't
+ * grab %POOL_MANAGING_WORKERS to achieve this because that can
+ * lead to idle worker depletion (all become busy thinking someone
+ * else is managing) which in turn can result in deadlock under
+ * extreme circumstances. Use @pool->manager_mutex to synchronize
+ * manager against CPU hotplug.
+ *
+ * manager_mutex would always be free unless CPU hotplug is in
+ * progress. trylock first without dropping @gcwq->lock.
+ */
+ if (unlikely(!mutex_trylock(&pool->manager_mutex))) {
+ spin_unlock_irq(&pool->gcwq->lock);
+ mutex_lock(&pool->manager_mutex);
+ /*
+ * CPU hotplug could have happened while we were waiting
+ * for manager_mutex. Hotplug itself can't handle us
+ * because manager isn't either on idle or busy list, and
+ * @gcwq's state and ours could have deviated.
+ *
+ * As hotplug is now excluded via manager_mutex, we can
+ * simply try to bind. It will succeed or fail depending
+ * on @gcwq's current state. Try it and adjust
+ * %WORKER_UNBOUND accordingly.
+ */
+ if (worker_maybe_bind_and_lock(worker))
+ worker->flags &= ~WORKER_UNBOUND;
+ else
+ worker->flags |= WORKER_UNBOUND;
+
+ ret = true;
+ }
+
pool->flags &= ~POOL_MANAGE_WORKERS;
/*
@@ -1806,6 +1873,7 @@ static bool manage_workers(struct worker *worker)
ret |= maybe_destroy_workers(pool);
ret |= maybe_create_worker(pool);
+ pool->flags &= ~POOL_MANAGING_WORKERS;
mutex_unlock(&pool->manager_mutex);
return ret;
}
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