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authorMaxime Ripard <mripard@kernel.org>2026-03-12 08:25:41 +0100
committerMaxime Ripard <mripard@kernel.org>2026-03-12 08:25:41 +0100
commitf08ceb71c5a5615577e7c841e1e00a89f495ab51 (patch)
treea024ee0aa3a8c5f3da518c7a9e15c6be131dd4f5 /kernel/trace/ring_buffer.c
parentf66d6cc6891e41be96380261943837b1909107b3 (diff)
parent58351f46de26bcc4403f9972f7aed430d15cbd03 (diff)
Merge drm/drm-next into drm-misc-next
Biju Das needs a patch for rz-du merged in 7.0-rc3 Signed-off-by: Maxime Ripard <mripard@kernel.org>
Diffstat (limited to 'kernel/trace/ring_buffer.c')
-rw-r--r--kernel/trace/ring_buffer.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index f16f053ef77d..17d0ea0cc3e6 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -7310,6 +7310,27 @@ int ring_buffer_map(struct trace_buffer *buffer, int cpu,
return err;
}
+/*
+ * This is called when a VMA is duplicated (e.g., on fork()) to increment
+ * the user_mapped counter without remapping pages.
+ */
+void ring_buffer_map_dup(struct trace_buffer *buffer, int cpu)
+{
+ struct ring_buffer_per_cpu *cpu_buffer;
+
+ if (WARN_ON(!cpumask_test_cpu(cpu, buffer->cpumask)))
+ return;
+
+ cpu_buffer = buffer->buffers[cpu];
+
+ guard(mutex)(&cpu_buffer->mapping_lock);
+
+ if (cpu_buffer->user_mapped)
+ __rb_inc_dec_mapped(cpu_buffer, true);
+ else
+ WARN(1, "Unexpected buffer stat, it should be mapped");
+}
+
int ring_buffer_unmap(struct trace_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;