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authorLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 12:02:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 12:02:25 -0800
commitda184a8064efe2a78d8542877970f7c6bb62775a (patch)
treed10193bb583f60333e243fe46386cab31f591e0c /kernel/trace/ring_buffer.c
parent525995d77ca08dfc2ba6f8e606f93694271dbd66 (diff)
parente36c54582c6f14adc9e10473e2aec2cc4f0acc03 (diff)
Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: tracing: Fix return of trace_dump_stack() ksym_tracer: Fix bad cast tracing/power: Remove two exports tracing: Change event->profile_count to be int type tracing: Simplify trace_option_write() tracing: Remove useless trace option tracing: Use seq file for trace_clock tracing: Use seq file for trace_options function-graph: Allow writing the same val to set_graph_function ftrace: Call trace_parser_clear() properly ftrace: Return EINVAL when writing invalid val to set_ftrace_filter tracing: Move a printk out of ftrace_raw_reg_event_foo() tracing: Pull up calls to trace_define_common_fields() tracing: Extract duplicate ftrace_raw_init_event_foo() ftrace.h: Use common pr_info fmt string tracing: Add stack trace to irqsoff tracer tracing: Add trace_dump_stack() ring-buffer: Move resize integrity check under reader lock ring-buffer: Use sync sched protection on ring buffer resizing tracing: Fix wrong usage of strstrip in trace_ksyms
Diffstat (limited to 'kernel/trace/ring_buffer.c')
-rw-r--r--kernel/trace/ring_buffer.c29
1 files changed, 11 insertions, 18 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index f58c9ad1583..2326b04c95c 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1193,9 +1193,6 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
struct list_head *p;
unsigned i;
- atomic_inc(&cpu_buffer->record_disabled);
- synchronize_sched();
-
spin_lock_irq(&cpu_buffer->reader_lock);
rb_head_page_deactivate(cpu_buffer);
@@ -1211,12 +1208,9 @@ 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);
- atomic_dec(&cpu_buffer->record_disabled);
-
+ spin_unlock_irq(&cpu_buffer->reader_lock);
}
static void
@@ -1227,9 +1221,6 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
struct list_head *p;
unsigned i;
- atomic_inc(&cpu_buffer->record_disabled);
- synchronize_sched();
-
spin_lock_irq(&cpu_buffer->reader_lock);
rb_head_page_deactivate(cpu_buffer);
@@ -1242,11 +1233,9 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
list_add_tail(&bpage->list, cpu_buffer->pages);
}
rb_reset_cpu(cpu_buffer);
- spin_unlock_irq(&cpu_buffer->reader_lock);
-
rb_check_pages(cpu_buffer);
- atomic_dec(&cpu_buffer->record_disabled);
+ spin_unlock_irq(&cpu_buffer->reader_lock);
}
/**
@@ -1254,11 +1243,6 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
* @buffer: the buffer to resize.
* @size: the new size.
*
- * The tracer is responsible for making sure that the buffer is
- * not being used while changing the size.
- * Note: We may be able to change the above requirement by using
- * RCU synchronizations.
- *
* Minimum size is 2 * BUF_PAGE_SIZE.
*
* Returns -1 on failure.
@@ -1290,6 +1274,11 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
if (size == buffer_size)
return size;
+ atomic_inc(&buffer->record_disabled);
+
+ /* Make sure all writers are done with this buffer. */
+ synchronize_sched();
+
mutex_lock(&buffer->mutex);
get_online_cpus();
@@ -1352,6 +1341,8 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
put_online_cpus();
mutex_unlock(&buffer->mutex);
+ atomic_dec(&buffer->record_disabled);
+
return size;
free_pages:
@@ -1361,6 +1352,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
}
put_online_cpus();
mutex_unlock(&buffer->mutex);
+ atomic_dec(&buffer->record_disabled);
return -ENOMEM;
/*
@@ -1370,6 +1362,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
out_fail:
put_online_cpus();
mutex_unlock(&buffer->mutex);
+ atomic_dec(&buffer->record_disabled);
return -1;
}
EXPORT_SYMBOL_GPL(ring_buffer_resize);