[src/thorpej-futex2]: src/sys/kern Isolate knowledge of the union-ness of fut...

[thorpej <thorpej%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7b2c7abe0730
branches:  thorpej-futex2
changeset: 1022748:7b2c7abe0730
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Fri Aug 06 23:53:53 2021 +0000

description:
Isolate knowledge of the union-ness of futex_key to where it's declared.

diffstat:

 sys/kern/sys_futex.c |  33 ++++++++++++++++++---------------
 1 files changed, 18 insertions(+), 15 deletions(-)

diffs (122 lines):

diff -r 5fff68c0eeba -r 7b2c7abe0730 sys/kern/sys_futex.c
--- a/sys/kern/sys_futex.c      Fri Aug 06 18:23:57 2021 +0000
+++ b/sys/kern/sys_futex.c      Fri Aug 06 23:53:53 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: sys_futex.c,v 1.12.4.3 2021/08/06 18:23:57 thorpej Exp $       */
+/*     $NetBSD: sys_futex.c,v 1.12.4.4 2021/08/06 23:53:53 thorpej Exp $       */
 
 /*-
  * Copyright (c) 2018, 2019, 2020 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_futex.c,v 1.12.4.3 2021/08/06 18:23:57 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_futex.c,v 1.12.4.4 2021/08/06 23:53:53 thorpej Exp $");
 
 /*
  * Futexes
@@ -190,13 +190,16 @@
  *     A futex is addressed either by a vmspace+va (private) or by
  *     a uvm_voaddr (shared).
  */
-union futex_key {
+typedef union futex_key {
        struct {
                struct vmspace                  *vmspace;
                vaddr_t                         va;
        }                       fk_private;
        struct uvm_voaddr       fk_shared;
-};
+} futex_key_t;
+
+CTASSERT(offsetof(futex_key_t, fk_private.va) ==
+        offsetof(futex_key_t, fk_shared.offset));
 
 /*
  * struct futex
@@ -217,7 +220,7 @@
  *     XXX field of the key.  Worth it?
  */
 struct futex {
-       union futex_key         fx_key;
+       futex_key_t             fx_key;
        struct rb_node          fx_node;
        unsigned long           fx_refcnt;
        bool                    fx_shared;
@@ -284,8 +287,8 @@
 compare_futex_key(void *cookie, const void *n, const void *k)
 {
        const struct futex *fa = n;
-       const union futex_key *fka = &fa->fx_key;
-       const union futex_key *fkb = k;
+       const futex_key_t *fka = &fa->fx_key;
+       const futex_key_t *fkb = k;
 
        if ((uintptr_t)fka->fk_private.vmspace <
            (uintptr_t)fkb->fk_private.vmspace)
@@ -319,8 +322,8 @@
 compare_futex_shared_key(void *cookie, const void *n, const void *k)
 {
        const struct futex *fa = n;
-       const union futex_key *fka = &fa->fx_key;
-       const union futex_key *fkb = k;
+       const futex_key_t *fka = &fa->fx_key;
+       const futex_key_t *fkb = k;
 
        return uvm_voaddr_compare(&fka->fk_shared, &fkb->fk_shared);
 }
@@ -539,7 +542,7 @@
  *     Initialize a futex key for lookup, etc.
  */
 static int
-futex_key_init(union futex_key *fk, struct vmspace *vm, vaddr_t va, bool shared)
+futex_key_init(futex_key_t *fk, struct vmspace *vm, vaddr_t va, bool shared)
 {
        int error = 0;
 
@@ -560,7 +563,7 @@
  *     Release a futex key.
  */
 static void
-futex_key_fini(union futex_key *fk, bool shared)
+futex_key_fini(futex_key_t *fk, bool shared)
 {
        if (__predict_false(shared))
                uvm_voaddr_release(&fk->fk_shared);
@@ -578,7 +581,7 @@
  *     Never sleeps for memory, but may sleep to acquire a lock.
  */
 static struct futex *
-futex_create(union futex_key *fk, bool shared, uint8_t class)
+futex_create(futex_key_t *fk, bool shared, uint8_t class)
 {
        struct futex *f;
 
@@ -725,7 +728,7 @@
  *     futex_lookup_create().
  */
 static int
-futex_lookup_by_key(union futex_key *fk, bool shared, uint8_t class,
+futex_lookup_by_key(futex_key_t *fk, bool shared, uint8_t class,
     struct futex **fp)
 {
        struct futex *f;
@@ -804,7 +807,7 @@
 static int
 futex_lookup(int *uaddr, bool shared, uint8_t class, struct futex **fp)
 {
-       union futex_key fk;
+       futex_key_t fk;
        struct vmspace *vm = curproc->p_vmspace;
        vaddr_t va = (vaddr_t)uaddr;
        int error;
@@ -852,7 +855,7 @@
 static int
 futex_lookup_create(int *uaddr, bool shared, uint8_t class, struct futex **fp)
 {
-       union futex_key fk;
+       futex_key_t fk;
        struct vmspace *vm = curproc->p_vmspace;
        struct futex *f = NULL;
        vaddr_t va = (vaddr_t)uaddr;