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@@ -70,23 +70,6 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
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unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
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-/*
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- * Only trace on a CPU if the bitmask is set:
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- */
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-static cpumask_t tracing_cpumask __read_mostly = CPU_MASK_ALL;
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-
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-/*
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- * The tracer itself will not take this lock, but still we want
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- * to provide a consistent cpumask to user-space:
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- */
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-static DEFINE_MUTEX(tracing_cpumask_update_lock);
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-
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-/*
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- * Temporary storage for the character representation of the
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- * CPU bitmask:
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- */
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-static char mask_str[NR_CPUS];
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-
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void trace_wake_up(void)
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{
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/*
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@@ -1776,19 +1759,46 @@ static struct file_operations show_traces_fops = {
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.release = seq_release,
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};
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+/*
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+ * Only trace on a CPU if the bitmask is set:
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+ */
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+static cpumask_t tracing_cpumask = CPU_MASK_ALL;
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+
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+/*
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+ * When tracing/tracing_cpu_mask is modified then this holds
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+ * the new bitmask we are about to install:
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+ */
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+static cpumask_t tracing_cpumask_new;
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+
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+/*
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+ * The tracer itself will not take this lock, but still we want
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+ * to provide a consistent cpumask to user-space:
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+ */
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+static DEFINE_MUTEX(tracing_cpumask_update_lock);
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+
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+/*
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+ * Temporary storage for the character representation of the
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+ * CPU bitmask (and one more byte for the newline):
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+ */
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+static char mask_str[NR_CPUS + 1];
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+
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static ssize_t
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tracing_cpumask_read(struct file *filp, char __user *ubuf,
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size_t count, loff_t *ppos)
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{
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- int err;
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-
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- count = min(count, (size_t)NR_CPUS);
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+ int len;
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mutex_lock(&tracing_cpumask_update_lock);
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- cpumask_scnprintf(mask_str, NR_CPUS, tracing_cpumask);
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- err = copy_to_user(ubuf, mask_str, count);
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- if (err)
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- count = -EFAULT;
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+
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+ len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
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+ if (count - len < 2) {
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+ count = -EINVAL;
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+ goto out_err;
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+ }
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+ len += sprintf(mask_str + len, "\n");
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+ count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
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+
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+out_err:
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mutex_unlock(&tracing_cpumask_update_lock);
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return count;
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@@ -1798,16 +1808,40 @@ static ssize_t
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tracing_cpumask_write(struct file *filp, const char __user *ubuf,
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size_t count, loff_t *ppos)
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{
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- int err;
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+ int err, cpu;
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mutex_lock(&tracing_cpumask_update_lock);
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- err = cpumask_parse_user(ubuf, count, tracing_cpumask);
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- mutex_unlock(&tracing_cpumask_update_lock);
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-
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+ err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
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if (err)
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- return err;
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+ goto err_unlock;
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+
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+ spin_lock_irq(&ftrace_max_lock);
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+ for_each_possible_cpu(cpu) {
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+ /*
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+ * Increase/decrease the disabled counter if we are
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+ * about to flip a bit in the cpumask:
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+ */
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+ if (cpu_isset(cpu, tracing_cpumask) &&
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+ !cpu_isset(cpu, tracing_cpumask_new)) {
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+ atomic_inc(&global_trace.data[cpu]->disabled);
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+ }
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+ if (!cpu_isset(cpu, tracing_cpumask) &&
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+ cpu_isset(cpu, tracing_cpumask_new)) {
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+ atomic_dec(&global_trace.data[cpu]->disabled);
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+ }
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+ }
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+ spin_unlock_irq(&ftrace_max_lock);
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+
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+ tracing_cpumask = tracing_cpumask_new;
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+
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+ mutex_unlock(&tracing_cpumask_update_lock);
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return count;
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+
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+err_unlock:
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+ mutex_unlock(&tracing_cpumask_update_lock);
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+
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+ return err;
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}
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static struct file_operations tracing_cpumask_fops = {
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@@ -1846,8 +1880,7 @@ tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
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r += sprintf(buf + r, "\n");
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WARN_ON(r >= len + 2);
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- r = simple_read_from_buffer(ubuf, cnt, ppos,
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- buf, r);
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+ r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
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kfree(buf);
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