perf: Make rb_alloc_aux() return an error immediately if nr_pages <= 0

rb_alloc_aux() should not be called with nr_pages <= 0. Make it more robust
and readable by returning an error immediately in that case.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240624201101.60186-8-adrian.hunter@intel.com

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 485cf0a66631b6305d9ec36b33981a8e264816f2..8cadf97bc2901aaf4f9bb6d6c9149dc90c035360 100644 (file)
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -682,6 +682,9 @@ int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event,
        if (!has_aux(event))
                return -EOPNOTSUPP;
 
+       if (nr_pages <= 0)
+               return -EINVAL;
+
        if (!overwrite) {
                /*
                 * Watermark defaults to half the buffer, and so does the