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-rw-r--r--kernel/fork.c2
-rw-r--r--kernel/futex.c6
-rw-r--r--kernel/kthread.c23
-rw-r--r--kernel/perf_event.c66
-rw-r--r--kernel/power/hibernate.c11
-rw-r--r--kernel/power/swap.c43
-rw-r--r--kernel/sched.c40
-rw-r--r--kernel/sched_fair.c73
-rw-r--r--kernel/trace/ftrace.c8
-rw-r--r--kernel/trace/ring_buffer.c14
-rw-r--r--kernel/trace/trace.c8
-rw-r--r--kernel/trace/trace_output.c5
12 files changed, 179 insertions, 120 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 4c20fff8c13..166b8c49257 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -91,7 +91,7 @@ int nr_processes(void)
int cpu;
int total = 0;
- for_each_online_cpu(cpu)
+ for_each_possible_cpu(cpu)
total += per_cpu(process_counts, cpu);
return total;
diff --git a/kernel/futex.c b/kernel/futex.c
index 642f3bbaacc..fb65e822fc4 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2127,7 +2127,7 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb,
plist_del(&q->list, &q->list.plist);
/* Handle spurious wakeups gracefully */
- ret = -EAGAIN;
+ ret = -EWOULDBLOCK;
if (timeout && !timeout->task)
ret = -ETIMEDOUT;
else if (signal_pending(current))
@@ -2208,7 +2208,6 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, int fshared,
debug_rt_mutex_init_waiter(&rt_waiter);
rt_waiter.task = NULL;
-retry:
key2 = FUTEX_KEY_INIT;
ret = get_futex_key(uaddr2, fshared, &key2, VERIFY_WRITE);
if (unlikely(ret != 0))
@@ -2303,9 +2302,6 @@ out_put_keys:
out_key2:
put_futex_key(fshared, &key2);
- /* Spurious wakeup ? */
- if (ret == -EAGAIN)
- goto retry;
out:
if (to) {
hrtimer_cancel(&to->timer);
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 5fe709982ca..ab7ae57773e 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -150,29 +150,6 @@ struct task_struct *kthread_create(int (*threadfn)(void *data),
EXPORT_SYMBOL(kthread_create);
/**
- * kthread_bind - bind a just-created kthread to a cpu.
- * @k: thread created by kthread_create().
- * @cpu: cpu (might not be online, must be possible) for @k to run on.
- *
- * Description: This function is equivalent to set_cpus_allowed(),
- * except that @cpu doesn't need to be online, and the thread must be
- * stopped (i.e., just returned from kthread_create()).
- */
-void kthread_bind(struct task_struct *k, unsigned int cpu)
-{
- /* Must have done schedule() in kthread() before we set_task_cpu */
- if (!wait_task_inactive(k, TASK_UNINTERRUPTIBLE)) {
- WARN_ON(1);
- return;
- }
- set_task_cpu(k, cpu);
- k->cpus_allowed = cpumask_of_cpu(cpu);
- k->rt.nr_cpus_allowed = 1;
- k->flags |= PF_THREAD_BOUND;
-}
-EXPORT_SYMBOL(kthread_bind);
-
-/**
* kthread_stop - stop a thread created by kthread_create().
* @k: thread created by kthread_create().
*
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index afb7ef3dbc4..7f29643c898 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3959,8 +3959,9 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
regs = task_pt_regs(current);
if (regs) {
- if (perf_event_overflow(event, 0, &data, regs))
- ret = HRTIMER_NORESTART;
+ if (!(event->attr.exclude_idle && current->pid == 0))
+ if (perf_event_overflow(event, 0, &data, regs))
+ ret = HRTIMER_NORESTART;
}
period = max_t(u64, 10000, event->hw.sample_period);
@@ -3969,6 +3970,42 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
return ret;
}
+static void perf_swevent_start_hrtimer(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ hwc->hrtimer.function = perf_swevent_hrtimer;
+ if (hwc->sample_period) {
+ u64 period;
+
+ if (hwc->remaining) {
+ if (hwc->remaining < 0)
+ period = 10000;
+ else
+ period = hwc->remaining;
+ hwc->remaining = 0;
+ } else {
+ period = max_t(u64, 10000, hwc->sample_period);
+ }
+ __hrtimer_start_range_ns(&hwc->hrtimer,
+ ns_to_ktime(period), 0,
+ HRTIMER_MODE_REL, 0);
+ }
+}
+
+static void perf_swevent_cancel_hrtimer(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (hwc->sample_period) {
+ ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
+ hwc->remaining = ktime_to_ns(remaining);
+
+ hrtimer_cancel(&hwc->hrtimer);
+ }
+}
+
/*
* Software event: cpu wall time clock
*/
@@ -3991,22 +4028,14 @@ static int cpu_clock_perf_event_enable(struct perf_event *event)
int cpu = raw_smp_processor_id();
atomic64_set(&hwc->prev_count, cpu_clock(cpu));
- hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- hwc->hrtimer.function = perf_swevent_hrtimer;
- if (hwc->sample_period) {
- u64 period = max_t(u64, 10000, hwc->sample_period);
- __hrtimer_start_range_ns(&hwc->hrtimer,
- ns_to_ktime(period), 0,
- HRTIMER_MODE_REL, 0);
- }
+ perf_swevent_start_hrtimer(event);
return 0;
}
static void cpu_clock_perf_event_disable(struct perf_event *event)
{
- if (event->hw.sample_period)
- hrtimer_cancel(&event->hw.hrtimer);
+ perf_swevent_cancel_hrtimer(event);
cpu_clock_perf_event_update(event);
}
@@ -4043,22 +4072,15 @@ static int task_clock_perf_event_enable(struct perf_event *event)
now = event->ctx->time;
atomic64_set(&hwc->prev_count, now);
- hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
- hwc->hrtimer.function = perf_swevent_hrtimer;
- if (hwc->sample_period) {
- u64 period = max_t(u64, 10000, hwc->sample_period);
- __hrtimer_start_range_ns(&hwc->hrtimer,
- ns_to_ktime(period), 0,
- HRTIMER_MODE_REL, 0);
- }
+
+ perf_swevent_start_hrtimer(event);
return 0;
}
static void task_clock_perf_event_disable(struct perf_event *event)
{
- if (event->hw.sample_period)
- hrtimer_cancel(&event->hw.hrtimer);
+ perf_swevent_cancel_hrtimer(event);
task_clock_perf_event_update(event, event->ctx->time);
}
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 04b3a83d686..04a9e90d248 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -693,21 +693,22 @@ static int software_resume(void)
/* The snapshot device should not be opened while we're running */
if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
error = -EBUSY;
+ swsusp_close(FMODE_READ);
goto Unlock;
}
pm_prepare_console();
error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
if (error)
- goto Finish;
+ goto close_finish;
error = usermodehelper_disable();
if (error)
- goto Finish;
+ goto close_finish;
error = create_basic_memory_bitmaps();
if (error)
- goto Finish;
+ goto close_finish;
pr_debug("PM: Preparing processes for restore.\n");
error = prepare_processes();
@@ -719,6 +720,7 @@ static int software_resume(void)
pr_debug("PM: Reading hibernation image.\n");
error = swsusp_read(&flags);
+ swsusp_close(FMODE_READ);
if (!error)
hibernation_restore(flags & SF_PLATFORM_MODE);
@@ -737,6 +739,9 @@ static int software_resume(void)
mutex_unlock(&pm_mutex);
pr_debug("PM: Resume from disk failed.\n");
return error;
+close_finish:
+ swsusp_close(FMODE_READ);
+ goto Finish;
}
late_initcall(software_resume);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index b101cdc4df3..890f6b11b1d 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -314,7 +314,6 @@ static int save_image(struct swap_map_handle *handle,
{
unsigned int m;
int ret;
- int error = 0;
int nr_pages;
int err2;
struct bio *bio;
@@ -329,26 +328,27 @@ static int save_image(struct swap_map_handle *handle,
nr_pages = 0;
bio = NULL;
do_gettimeofday(&start);
- do {
+ while (1) {
ret = snapshot_read_next(snapshot, PAGE_SIZE);
- if (ret > 0) {
- error = swap_write_page(handle, data_of(*snapshot),
- &bio);
- if (error)
- break;
- if (!(nr_pages % m))
- printk("\b\b\b\b%3d%%", nr_pages / m);
- nr_pages++;
- }
- } while (ret > 0);
+ if (ret <= 0)
+ break;
+ ret = swap_write_page(handle, data_of(*snapshot), &bio);
+ if (ret)
+ break;
+ if (!(nr_pages % m))
+ printk("\b\b\b\b%3d%%", nr_pages / m);
+ nr_pages++;
+ }
err2 = wait_on_bio_chain(&bio);
do_gettimeofday(&stop);
- if (!error)
- error = err2;
- if (!error)
+ if (!ret)
+ ret = err2;
+ if (!ret)
printk("\b\b\b\bdone\n");
+ else
+ printk("\n");
swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
- return error;
+ return ret;
}
/**
@@ -536,7 +536,8 @@ static int load_image(struct swap_map_handle *handle,
snapshot_write_finalize(snapshot);
if (!snapshot_image_loaded(snapshot))
error = -ENODATA;
- }
+ } else
+ printk("\n");
swsusp_show_speed(&start, &stop, nr_to_read, "Read");
return error;
}
@@ -572,8 +573,6 @@ int swsusp_read(unsigned int *flags_p)
error = load_image(&handle, &snapshot, header->pages - 1);
release_swap_reader(&handle);
- blkdev_put(resume_bdev, FMODE_READ);
-
if (!error)
pr_debug("PM: Image successfully loaded\n");
else
@@ -596,7 +595,7 @@ int swsusp_check(void)
error = bio_read_page(swsusp_resume_block,
swsusp_header, NULL);
if (error)
- return error;
+ goto put;
if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
@@ -604,8 +603,10 @@ int swsusp_check(void)
error = bio_write_page(swsusp_resume_block,
swsusp_header, NULL);
} else {
- return -EINVAL;
+ error = -EINVAL;
}
+
+put:
if (error)
blkdev_put(resume_bdev, FMODE_READ);
else
diff --git a/kernel/sched.c b/kernel/sched.c
index a455dca884a..28dd4f490bf 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1992,6 +1992,38 @@ static inline void check_class_changed(struct rq *rq, struct task_struct *p,
p->sched_class->prio_changed(rq, p, oldprio, running);
}
+/**
+ * kthread_bind - bind a just-created kthread to a cpu.
+ * @k: thread created by kthread_create().
+ * @cpu: cpu (might not be online, must be possible) for @k to run on.
+ *
+ * Description: This function is equivalent to set_cpus_allowed(),
+ * except that @cpu doesn't need to be online, and the thread must be
+ * stopped (i.e., just returned from kthread_create()).
+ *
+ * Function lives here instead of kthread.c because it messes with
+ * scheduler internals which require locking.
+ */
+void kthread_bind(struct task_struct *p, unsigned int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long flags;
+
+ /* Must have done schedule() in kthread() before we set_task_cpu */
+ if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE)) {
+ WARN_ON(1);
+ return;
+ }
+
+ spin_lock_irqsave(&rq->lock, flags);
+ set_task_cpu(p, cpu);
+ p->cpus_allowed = cpumask_of_cpu(cpu);
+ p->rt.nr_cpus_allowed = 1;
+ p->flags |= PF_THREAD_BOUND;
+ spin_unlock_irqrestore(&rq->lock, flags);
+}
+EXPORT_SYMBOL(kthread_bind);
+
#ifdef CONFIG_SMP
/*
* Is this task likely cache-hot:
@@ -2004,7 +2036,7 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
/*
* Buddy candidates are cache hot:
*/
- if (sched_feat(CACHE_HOT_BUDDY) &&
+ if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
(&p->se == cfs_rq_of(&p->se)->next ||
&p->se == cfs_rq_of(&p->se)->last))
return 1;
@@ -9532,13 +9564,13 @@ void __init sched_init(void)
current->sched_class = &fair_sched_class;
/* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
- alloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
+ zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
#ifdef CONFIG_SMP
#ifdef CONFIG_NO_HZ
- alloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
+ zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
#endif
- alloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+ zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
#endif /* SMP */
perf_event_init();
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index c32c3e643da..37087a7fac2 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -822,6 +822,26 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
* re-elected due to buddy favours.
*/
clear_buddies(cfs_rq, curr);
+ return;
+ }
+
+ /*
+ * Ensure that a task that missed wakeup preemption by a
+ * narrow margin doesn't have to wait for a full slice.
+ * This also mitigates buddy induced latencies under load.
+ */
+ if (!sched_feat(WAKEUP_PREEMPT))
+ return;
+
+ if (delta_exec < sysctl_sched_min_granularity)
+ return;
+
+ if (cfs_rq->nr_running > 1) {
+ struct sched_entity *se = __pick_next_entity(cfs_rq);
+ s64 delta = curr->vruntime - se->vruntime;
+
+ if (delta > ideal_runtime)
+ resched_task(rq_of(cfs_rq)->curr);
}
}
@@ -861,21 +881,18 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se);
static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq)
{
struct sched_entity *se = __pick_next_entity(cfs_rq);
- struct sched_entity *buddy;
+ struct sched_entity *left = se;
- if (cfs_rq->next) {
- buddy = cfs_rq->next;
- cfs_rq->next = NULL;
- if (wakeup_preempt_entity(buddy, se) < 1)
- return buddy;
- }
+ if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1)
+ se = cfs_rq->next;
- if (cfs_rq->last) {
- buddy = cfs_rq->last;
- cfs_rq->last = NULL;
- if (wakeup_preempt_entity(buddy, se) < 1)
- return buddy;
- }
+ /*
+ * Prefer last buddy, try to return the CPU to a preempted task.
+ */
+ if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1)
+ se = cfs_rq->last;
+
+ clear_buddies(cfs_rq, se);
return se;
}
@@ -1577,6 +1594,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
struct sched_entity *se = &curr->se, *pse = &p->se;
struct cfs_rq *cfs_rq = task_cfs_rq(curr);
int sync = wake_flags & WF_SYNC;
+ int scale = cfs_rq->nr_running >= sched_nr_latency;
update_curr(cfs_rq);
@@ -1591,18 +1609,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
if (unlikely(se == pse))
return;
- /*
- * Only set the backward buddy when the current task is still on the
- * rq. This can happen when a wakeup gets interleaved with schedule on
- * the ->pre_schedule() or idle_balance() point, either of which can
- * drop the rq lock.
- *
- * Also, during early boot the idle thread is in the fair class, for
- * obvious reasons its a bad idea to schedule back to the idle thread.
- */
- if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle))
- set_last_buddy(se);
- if (sched_feat(NEXT_BUDDY) && !(wake_flags & WF_FORK))
+ if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK))
set_next_buddy(pse);
/*
@@ -1648,8 +1655,22 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
BUG_ON(!pse);
- if (wakeup_preempt_entity(se, pse) == 1)
+ if (wakeup_preempt_entity(se, pse) == 1) {
resched_task(curr);
+ /*
+ * Only set the backward buddy when the current task is still
+ * on the rq. This can happen when a wakeup gets interleaved
+ * with schedule on the ->pre_schedule() or idle_balance()
+ * point, either of which can * drop the rq lock.
+ *
+ * Also, during early boot the idle thread is in the fair class,
+ * for obvious reasons its a bad idea to schedule back to it.
+ */
+ if (unlikely(!se->on_rq || curr == rq->idle))
+ return;
+ if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se))
+ set_last_buddy(se);
+ }
}
static struct task_struct *pick_next_task_fair(struct rq *rq)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 37ba67e3326..6dc4e5ef7a0 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -740,7 +740,7 @@ ftrace_profile_write(struct file *filp, const char __user *ubuf,
out:
mutex_unlock(&ftrace_profile_lock);
- filp->f_pos += cnt;
+ *ppos += cnt;
return cnt;
}
@@ -2222,15 +2222,15 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
ret = ftrace_process_regex(parser->buffer,
parser->idx, enable);
if (ret)
- goto out;
+ goto out_unlock;
trace_parser_clear(parser);
}
ret = read;
-
+out_unlock:
mutex_unlock(&ftrace_regex_lock);
-out:
+
return ret;
}
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index d4ff0197054..5dd017fea6f 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -483,7 +483,7 @@ struct ring_buffer_iter {
/* Up this if you want to test the TIME_EXTENTS and normalization */
#define DEBUG_SHIFT 0
-static inline u64 rb_time_stamp(struct ring_buffer *buffer, int cpu)
+static inline u64 rb_time_stamp(struct ring_buffer *buffer)
{
/* shift to debug/test normalization and TIME_EXTENTS */
return buffer->clock() << DEBUG_SHIFT;
@@ -494,7 +494,7 @@ u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu)
u64 time;
preempt_disable_notrace();
- time = rb_time_stamp(buffer, cpu);
+ time = rb_time_stamp(buffer);
preempt_enable_no_resched_notrace();
return time;
@@ -599,7 +599,7 @@ static struct list_head *rb_list_head(struct list_head *list)
}
/*
- * rb_is_head_page - test if the give page is the head page
+ * rb_is_head_page - test if the given page is the head page
*
* Because the reader may move the head_page pointer, we can
* not trust what the head page is (it may be pointing to
@@ -1193,6 +1193,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
atomic_inc(&cpu_buffer->record_disabled);
synchronize_sched();
+ spin_lock_irq(&cpu_buffer->reader_lock);
rb_head_page_deactivate(cpu_buffer);
for (i = 0; i < nr_pages; i++) {
@@ -1207,6 +1208,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
return;
rb_reset_cpu(cpu_buffer);
+ spin_unlock_irq(&cpu_buffer->reader_lock);
rb_check_pages(cpu_buffer);
@@ -1868,7 +1870,7 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
* Nested commits always have zero deltas, so
* just reread the time stamp
*/
- *ts = rb_time_stamp(buffer, cpu_buffer->cpu);
+ *ts = rb_time_stamp(buffer);
next_page->page->time_stamp = *ts;
}
@@ -2111,7 +2113,7 @@ rb_reserve_next_event(struct ring_buffer *buffer,
if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
goto out_fail;
- ts = rb_time_stamp(cpu_buffer->buffer, cpu_buffer->cpu);
+ ts = rb_time_stamp(cpu_buffer->buffer);
/*
* Only the first commit can update the timestamp.
@@ -2681,7 +2683,7 @@ unsigned long ring_buffer_entries(struct ring_buffer *buffer)
EXPORT_SYMBOL_GPL(ring_buffer_entries);
/**
- * ring_buffer_overrun_cpu - get the number of overruns in buffer
+ * ring_buffer_overruns - get the number of overruns in buffer
* @buffer: The ring buffer
*
* Returns the total number of overruns in the ring buffer
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c820b0310a1..b20d3ec75de 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2440,7 +2440,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
return ret;
}
- filp->f_pos += cnt;
+ *ppos += cnt;
return cnt;
}
@@ -2582,7 +2582,7 @@ tracing_ctrl_write(struct file *filp, const char __user *ubuf,
}
mutex_unlock(&trace_types_lock);
- filp->f_pos += cnt;
+ *ppos += cnt;
return cnt;
}
@@ -2764,7 +2764,7 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
if (err)
return err;
- filp->f_pos += ret;
+ *ppos += ret;
return ret;
}
@@ -3299,7 +3299,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
}
}
- filp->f_pos += cnt;
+ *ppos += cnt;
/* If check pages failed, return ENOMEM */
if (tracing_disabled)
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index ed17565826b..b6c12c6a1bc 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -69,6 +69,9 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
* @s: trace sequence descriptor
* @fmt: printf format string
*
+ * It returns 0 if the trace oversizes the buffer's free
+ * space, 1 otherwise.
+ *
* The tracer may use either sequence operations or its own
* copy to user routines. To simplify formating of a trace
* trace_seq_printf is used to store strings into a special
@@ -95,7 +98,7 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
s->len += ret;
- return len;
+ return 1;
}
EXPORT_SYMBOL_GPL(trace_seq_printf);
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-06 21:34:48 +0000