x86/alternatives: Use non-inverted logic instead of 'tp_order_fail()'

tp_order_fail() uses inverted logic: it returns true in case something
is false, which is only a plus at the IOCCC.

Instead rename it to regular parity as 'text_poke_addr_ordered()',
and adjust the code accordingly.

Also add a comment explaining how the address ordering should be
understood.

No change in functionality intended.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Juergen Gross <jgross@suse.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250411054105.2341982-23-mingo@kernel.org

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index c53eb3b0454eb82508c971915ba88527d273711d..c5801b4cbb66e5e80383faa77692462503fa4b6b 100644 (file)
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2841,28 +2841,34 @@ static void text_poke_int3_loc_init(struct smp_text_poke_loc *tp, void *addr,
  * We hard rely on the tp_vec being ordered; ensure this is so by flushing
  * early if needed.
  */
-static bool tp_order_fail(void *addr)
+static bool text_poke_addr_ordered(void *addr)
 {
        struct smp_text_poke_loc *tp;
 
        if (!tp_vec_nr)
-               return false;
+               return true;
 
        if (!addr) /* force */
-               return true;
+               return false;
 
-       tp = &tp_vec[tp_vec_nr - 1];
+       /*
+        * If the last current entry's address is higher than the
+        * new entry's address we'd like to add, then ordering
+        * is violated and we must first flush all pending patching
+        * requests:
+        */
+       tp = &tp_vec[tp_vec_nr-1];
        if ((unsigned long)text_poke_addr(tp) > (unsigned long)addr)
-               return true;
+               return false;
 
-       return false;
+       return true;
 }
 
 static void smp_text_poke_batch_flush(void *addr)
 {
        lockdep_assert_held(&text_mutex);
 
-       if (tp_vec_nr == TP_VEC_MAX || tp_order_fail(addr)) {
+       if (tp_vec_nr == TP_VEC_MAX || !text_poke_addr_ordered(addr)) {
                smp_text_poke_batch_process(tp_vec, tp_vec_nr);
                tp_vec_nr = 0;
        }