ring_buffer: fix ring_buffer_read_page()
Impact: change API and init bpage when copy ring_buffer_read_page()/rb_remove_entries() may be called for a partially consumed page. Add a parameter for rb_remove_entries() and make it update cpu_buffer->entries correctly for partially consumed pages. ring_buffer_read_page() now returns the offset to the next event. Init the bpage's time_stamp when return value is 0. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This commit is contained in:
Родитель
b85fa01ed9
Коммит
667d241258
|
@ -2332,13 +2332,14 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
|
||||||
EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
|
EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
|
||||||
|
|
||||||
static void rb_remove_entries(struct ring_buffer_per_cpu *cpu_buffer,
|
static void rb_remove_entries(struct ring_buffer_per_cpu *cpu_buffer,
|
||||||
struct buffer_data_page *bpage)
|
struct buffer_data_page *bpage,
|
||||||
|
unsigned int offset)
|
||||||
{
|
{
|
||||||
struct ring_buffer_event *event;
|
struct ring_buffer_event *event;
|
||||||
unsigned long head;
|
unsigned long head;
|
||||||
|
|
||||||
__raw_spin_lock(&cpu_buffer->lock);
|
__raw_spin_lock(&cpu_buffer->lock);
|
||||||
for (head = 0; head < local_read(&bpage->commit);
|
for (head = offset; head < local_read(&bpage->commit);
|
||||||
head += rb_event_length(event)) {
|
head += rb_event_length(event)) {
|
||||||
|
|
||||||
event = __rb_data_page_index(bpage, head);
|
event = __rb_data_page_index(bpage, head);
|
||||||
|
@ -2410,8 +2411,8 @@ void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data)
|
||||||
* if (!rpage)
|
* if (!rpage)
|
||||||
* return error;
|
* return error;
|
||||||
* ret = ring_buffer_read_page(buffer, &rpage, cpu, 0);
|
* ret = ring_buffer_read_page(buffer, &rpage, cpu, 0);
|
||||||
* if (ret)
|
* if (ret >= 0)
|
||||||
* process_page(rpage);
|
* process_page(rpage, ret);
|
||||||
*
|
*
|
||||||
* When @full is set, the function will not return true unless
|
* When @full is set, the function will not return true unless
|
||||||
* the writer is off the reader page.
|
* the writer is off the reader page.
|
||||||
|
@ -2422,8 +2423,8 @@ void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data)
|
||||||
* responsible for that.
|
* responsible for that.
|
||||||
*
|
*
|
||||||
* Returns:
|
* Returns:
|
||||||
* 1 if data has been transferred
|
* >=0 if data has been transferred, returns the offset of consumed data.
|
||||||
* 0 if no data has been transferred.
|
* <0 if no data has been transferred.
|
||||||
*/
|
*/
|
||||||
int ring_buffer_read_page(struct ring_buffer *buffer,
|
int ring_buffer_read_page(struct ring_buffer *buffer,
|
||||||
void **data_page, int cpu, int full)
|
void **data_page, int cpu, int full)
|
||||||
|
@ -2432,7 +2433,8 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
|
||||||
struct ring_buffer_event *event;
|
struct ring_buffer_event *event;
|
||||||
struct buffer_data_page *bpage;
|
struct buffer_data_page *bpage;
|
||||||
unsigned long flags;
|
unsigned long flags;
|
||||||
int ret = 0;
|
unsigned int read;
|
||||||
|
int ret = -1;
|
||||||
|
|
||||||
if (!data_page)
|
if (!data_page)
|
||||||
return 0;
|
return 0;
|
||||||
|
@ -2454,24 +2456,29 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
|
||||||
/* check for data */
|
/* check for data */
|
||||||
if (!local_read(&cpu_buffer->reader_page->page->commit))
|
if (!local_read(&cpu_buffer->reader_page->page->commit))
|
||||||
goto out;
|
goto out;
|
||||||
|
|
||||||
|
read = cpu_buffer->reader_page->read;
|
||||||
/*
|
/*
|
||||||
* If the writer is already off of the read page, then simply
|
* If the writer is already off of the read page, then simply
|
||||||
* switch the read page with the given page. Otherwise
|
* switch the read page with the given page. Otherwise
|
||||||
* we need to copy the data from the reader to the writer.
|
* we need to copy the data from the reader to the writer.
|
||||||
*/
|
*/
|
||||||
if (cpu_buffer->reader_page == cpu_buffer->commit_page) {
|
if (cpu_buffer->reader_page == cpu_buffer->commit_page) {
|
||||||
unsigned int read = cpu_buffer->reader_page->read;
|
|
||||||
unsigned int commit = rb_page_commit(cpu_buffer->reader_page);
|
unsigned int commit = rb_page_commit(cpu_buffer->reader_page);
|
||||||
|
struct buffer_data_page *rpage = cpu_buffer->reader_page->page;
|
||||||
|
|
||||||
if (full)
|
if (full)
|
||||||
goto out;
|
goto out;
|
||||||
/* The writer is still on the reader page, we must copy */
|
/* The writer is still on the reader page, we must copy */
|
||||||
memcpy(bpage->data,
|
memcpy(bpage->data + read, rpage->data + read, commit - read);
|
||||||
cpu_buffer->reader_page->page->data + read,
|
|
||||||
commit - read);
|
|
||||||
|
|
||||||
/* consume what was read */
|
/* consume what was read */
|
||||||
cpu_buffer->reader_page->read = commit;
|
cpu_buffer->reader_page->read = commit;
|
||||||
|
|
||||||
|
/* update bpage */
|
||||||
|
local_set(&bpage->commit, commit);
|
||||||
|
if (!read)
|
||||||
|
bpage->time_stamp = rpage->time_stamp;
|
||||||
} else {
|
} else {
|
||||||
/* swap the pages */
|
/* swap the pages */
|
||||||
rb_init_page(bpage);
|
rb_init_page(bpage);
|
||||||
|
@ -2480,10 +2487,10 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
|
||||||
cpu_buffer->reader_page->read = 0;
|
cpu_buffer->reader_page->read = 0;
|
||||||
*data_page = bpage;
|
*data_page = bpage;
|
||||||
}
|
}
|
||||||
ret = 1;
|
ret = read;
|
||||||
|
|
||||||
/* update the entry counter */
|
/* update the entry counter */
|
||||||
rb_remove_entries(cpu_buffer, bpage);
|
rb_remove_entries(cpu_buffer, bpage, read);
|
||||||
out:
|
out:
|
||||||
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
|
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
|
||||||
|
|
||||||
|
|
Загрузка…
Ссылка в новой задаче