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authorJonathan Cameron <Jonathan.Cameron@huawei.com>2026-03-22 12:20:42 +0000
committerJonathan Cameron <Jonathan.Cameron@huawei.com>2026-03-22 12:20:42 +0000
commit9e4e86a604dfd06402933467578c4b79f5412b2c (patch)
tree5cf2d962b699987c8a785e35a5f5c5f450532c0a /kernel/trace/ring_buffer.c
parente8b83499b4cbc8b989f7cd6aaa893b669326e93c (diff)
parentf338e77383789c0cae23ca3d48adcc5e9e137e3c (diff)
Merge tag 'v7.0-rc4' into togreg
Linux 7.0-rc4 Required for the ds4422 series which is build upon; 5187e03b817c ("iio: dac: ds4424: reject -128 RAW value")
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;