ring_buffer: fix typing mistake
Impact: Fix bug I found several very very curious line. It's so curious that it may be brought by typing mistake. When (cpu_buffer->reader_page == cpu_buffer->commit_page): 1) We haven't copied it for bpage is changed: bpage = cpu_buffer->reader_page->page; memcpy(bpage->data, cpu_buffer->reader_page->page->data + read ... ) 2) We need update cpu_buffer->reader_page->read, but "cpu_buffer->reader_page += read;" is not right. [ This bug was a typo. The commit->reader_page is a page pointer and not an index into the page. The line should have been commit->reader_page->read += read. The other changes by Lai are nice clean ups to the code. - SDR ] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
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@ -2406,7 +2406,7 @@ void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data)
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* to swap with a page in the ring buffer.
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*
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* for example:
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* rpage = ring_buffer_alloc_page(buffer);
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* rpage = ring_buffer_alloc_read_page(buffer);
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* if (!rpage)
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* return error;
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* ret = ring_buffer_read_page(buffer, &rpage, cpu, 0);
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@ -2461,18 +2461,17 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
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*/
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if (cpu_buffer->reader_page == cpu_buffer->commit_page) {
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unsigned int read = cpu_buffer->reader_page->read;
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unsigned int commit = rb_page_commit(cpu_buffer->reader_page);
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if (full)
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goto out;
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/* The writer is still on the reader page, we must copy */
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bpage = cpu_buffer->reader_page->page;
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memcpy(bpage->data,
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cpu_buffer->reader_page->page->data + read,
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local_read(&bpage->commit) - read);
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commit - read);
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/* consume what was read */
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cpu_buffer->reader_page += read;
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cpu_buffer->reader_page->read = commit;
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} else {
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/* swap the pages */
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rb_init_page(bpage);
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