addressing review comments

diff --git a/libbpf-tools/biolatency.bpf.c b/libbpf-tools/biolatency.bpf.c
index e9551ce58ccca123a8e3bd578b10182745f34dd2..3940a4690c61cf7e955cc292e89b12d166cf81b2 100644 (file)
--- a/libbpf-tools/biolatency.bpf.c
+++ b/libbpf-tools/biolatency.bpf.c
@@ -57,29 +57,42 @@ int trace_rq_start(struct request *rq)
 }
 
 SEC("tp_btf/block_rq_insert")
-int block_rq_insert (u64 *ctx)
+int block_rq_insert(u64 *ctx)
 {
        /**
         * commit a54895fa (v5.11-rc1) changed tracepoint argument list
         * from TP_PROTO(struct request_queue *q, struct request *rq)
         * to TP_PROTO(struct request *rq)
         */
-       struct request *rq = LINUX_KERNEL_VERSION >= KERNEL_VERSION(5, 11, 1) ? (void *)ctx[0] : (void *)ctx[1];
-       return trace_rq_start(rq);
+       if (LINUX_KERNEL_VERSION <= KERNEL_VERSION(5, 10, 0))
+               return trace_rq_start((void *)ctx[1]);
+       else
+               return trace_rq_start((void *)ctx[0]);
+}
+
+static __always_inline
+int f(u64 *ctx, int idx)
+{
+       /**
+        * Verifier happens to be more friendly to pointer arithmetic starting v5.11
+        */
+       if (targ_queued && BPF_CORE_READ(((struct request *)ctx[idx])->q, elevator))
+               return 0;
+       return trace_rq_start((void *)ctx[idx]);
 }
 
 SEC("tp_btf/block_rq_issue")
-int block_rq_issue (u64 *ctx)
+int block_rq_issue(u64 *ctx)
 {
        /**
         * commit a54895fa (v5.11-rc1) changed tracepoint argument list
         * from TP_PROTO(struct request_queue *q, struct request *rq)
         * to TP_PROTO(struct request *rq)
         */
-       struct request *rq = LINUX_KERNEL_VERSION >= KERNEL_VERSION(5, 11, 1) ? (void *)ctx[0] : (void *)ctx[1];
-       if (targ_queued && BPF_CORE_READ(rq->q, elevator))
-               return 0;
-       return trace_rq_start(rq);
+       if (LINUX_KERNEL_VERSION <= KERNEL_VERSION(5, 10, 0))
+               return f(ctx, 1);
+       else
+               return f(ctx, 0);
 }
 
 SEC("tp_btf/block_rq_complete")