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-rw-r--r--kernel/events/ring_buffer.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 232f00f273cb..725c416085e3 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -493,6 +493,20 @@ int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event,
rb->aux_pages[rb->aux_nr_pages] = page_address(page++);
}
+ /*
+ * In overwrite mode, PMUs that don't support SG may not handle more
+ * than one contiguous allocation, since they rely on PMI to do double
+ * buffering. In this case, the entire buffer has to be one contiguous
+ * chunk.
+ */
+ if ((event->pmu->capabilities & PERF_PMU_CAP_AUX_NO_SG) &&
+ overwrite) {
+ struct page *page = virt_to_page(rb->aux_pages[0]);
+
+ if (page_private(page) != max_order)
+ goto out;
+ }
+
rb->aux_priv = event->pmu->setup_aux(event->cpu, rb->aux_pages, nr_pages,
overwrite);
if (!rb->aux_priv)