From def510d20a47ce28f6b8b494f9212f9ee394aae2 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Fri, 26 Feb 2016 01:44:55 +0100
Subject: Document why code is not racy

* i386/i386at/kd_mouse.c (kd_mouse_read): Document why the
assert_wait/thread_block pair is not racy.
---
 i386/i386at/kd_mouse.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/i386/i386at/kd_mouse.c b/i386/i386at/kd_mouse.c
index 0f1881f4..ece13efe 100644
--- a/i386/i386at/kd_mouse.c
+++ b/i386/i386at/kd_mouse.c
@@ -630,6 +630,8 @@ int kd_mouse_read(void)
 	while (mousebufindex <= mouse_char_index) {
 	    mouse_char_wanted = TRUE;
 	    assert_wait((event_t) &mousebuf, FALSE);
+	    /* We are at tty SPL level, interrupts can not happen between
+	     * assert_wait and thread_block.  */
 	    thread_block((void (*)()) 0);
 	}
 
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