Instead of aged_tail use an iterator that starts from the hw_tail and goes backward until the oa_buffer.tail looking for valid reports.
Signed-off-by: Umesh Nerlige Ramappa <[email protected]> --- drivers/gpu/drm/i915/i915_perf.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index beb1269422ca..39f5ab1911c8 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -543,7 +543,7 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream) { u32 gtt_offset = i915_ggtt_offset(stream->oa_buffer.vma); int report_size = stream->oa_buffer.format->size; - u32 head, tail, aged_tail; + u32 head, tail, iter; unsigned long flags; bool pollin; u32 hw_tail; @@ -567,15 +567,14 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream) /* Subtract partial amount off the tail */ hw_tail = OA_TAKEN(hw_tail, partial_report_size); - /* NB: The head we observe here might effectively be a little * out of date. If a read() is in progress, the head could be * anywhere between this head and stream->oa_buffer.tail. */ head = stream->oa_buffer.head - gtt_offset; - aged_tail = stream->oa_buffer.tail - gtt_offset; + tail = stream->oa_buffer.tail - gtt_offset; - tail = hw_tail; + iter = hw_tail; /* Walk the stream backward until we find a report with report * id and timestmap not at 0. Since the circular buffer pointers @@ -588,23 +587,23 @@ static bool oa_buffer_check_unlocked(struct i915_perf_stream *stream) * memory in the order they were written to. * If not : (╯°□°）╯︵ ┻━┻ */ - while (OA_TAKEN(tail, aged_tail) >= report_size) { - void *report = stream->oa_buffer.vaddr + tail; + while (OA_TAKEN(iter, tail) >= report_size) { + void *report = stream->oa_buffer.vaddr + iter; if (oa_report_id(stream, report) || oa_timestamp(stream, report)) break; - tail = (tail - report_size) & (OA_BUFFER_SIZE - 1); + iter = (iter - report_size) & (OA_BUFFER_SIZE - 1); } - if (OA_TAKEN(hw_tail, tail) > report_size && + if (OA_TAKEN(hw_tail, iter) > report_size && __ratelimit(&stream->perf->tail_pointer_race)) drm_notice(&stream->uncore->i915->drm, "unlanded report(s) head=0x%x tail=0x%x hw_tail=0x%x\n", head, tail, hw_tail); - stream->oa_buffer.tail = gtt_offset + tail; + stream->oa_buffer.tail = gtt_offset + iter; pollin = OA_TAKEN(stream->oa_buffer.tail - gtt_offset, stream->oa_buffer.head - gtt_offset) >= report_size; -- 2.36.1
