From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Sat, 17 Aug 2013 17:09:40 +0000 (+0100)
Subject: overlay: Fix wraparound handling of perf ringbuffer
X-Git-Tag: intel-gpu-tools-1.4~193
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3e430a8b01ae13bac878863663bd3e2efd995c6d;p=platform%2Fupstream%2Fintel-gpu-tools.git

overlay: Fix wraparound handling of perf ringbuffer

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---

diff --git a/overlay/gpu-perf.c b/overlay/gpu-perf.c
index d2f09f5..7751132 100644
--- a/overlay/gpu-perf.c
+++ b/overlay/gpu-perf.c
@@ -226,7 +226,7 @@ int gpu_perf_update(struct gpu_perf *gp)
 		rmb();
 
 		if (head < tail)
-			tail = head; /* XXX */
+			head += size;
 
 		data = (uint8_t *)mmap + gp->page_size;
 		while (head - tail >= sizeof (struct perf_event_header)) {
@@ -262,7 +262,7 @@ int gpu_perf_update(struct gpu_perf *gp)
 			tail += header->size;
 		}
 
-		mmap->data_tail = tail;
+		mmap->data_tail = tail & mask;
 	}
 
 	free(buffer);