[tip:x86/alternatives] jump_label: Sort entries of the same key by the code

[tip-bot for Daniel Bristot de Oliveira]

Commit-ID:  1ca3398278341e1db3568f2d9c015ee4f5ad0b56
Gitweb:     https://git.kernel.org/tip/1ca3398278341e1db3568f2d9c015ee4f5ad0b56
Author:     Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
AuthorDate: Fri, 21 Dec 2018 11:27:31 +0100
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 19 Apr 2019 19:37:34 +0200

jump_label: Sort entries of the same key by the code

In the batching mode, entries with the same key should also be sorted by the
code, enabling a bsearch() of a code/addr when updating a key.

Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Chris von Recklinghausen <crecklin@xxxxxxxxxx>
Cc: Clark Williams <williams@xxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Scott Wood <swood@xxxxxxxxxx>
Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/7006ec86c40e5ec5d546dcd76ccc42d46079a963.1545228276.git.bristot@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 kernel/jump_label.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 456c0d7cbb5b..53b7c85c0b09 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -36,12 +36,28 @@ static int jump_label_cmp(const void *a, const void *b)
 	const struct jump_entry *jea = a;
 	const struct jump_entry *jeb = b;
 
+	/*
+	 * Entrires are sorted by key.
+	 */
 	if (jump_entry_key(jea) < jump_entry_key(jeb))
 		return -1;
 
 	if (jump_entry_key(jea) > jump_entry_key(jeb))
 		return 1;
 
+#ifdef HAVE_JUMP_LABEL_BATCH
+	/*
+	 * In the batching mode, entries should also be sorted by the code
+	 * inside the already sorted list of entries, enabling a bsearch in
+	 * the vector.
+	 */
+	if (jump_entry_code(jea) < jump_entry_code(jeb))
+		return -1;
+
+	if (jump_entry_code(jea) > jump_entry_code(jeb))
+		return 1;
+#endif
+
 	return 0;
 }