git: b04f5d18b5fa - main - linux(4): To improve readability use FUTEX_UNOWNED instead of 0

[Dmitry Chagin]

The branch main has been updated by dchagin:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=b04f5d18b5faad004a10f054d9c9072fcf31c29b

commit b04f5d18b5faad004a10f054d9c9072fcf31c29b
Author:     Dmitry Chagin <dcha...@freebsd.org>
AuthorDate: 2022-05-19 18:42:38 +0000
Commit:     Dmitry Chagin <dcha...@freebsd.org>
CommitDate: 2022-05-19 18:42:38 +0000

    linux(4): To improve readability use FUTEX_UNOWNED instead of 0
    
    MFC after:              2 weeks
---
 sys/compat/linux/linux_futex.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c
index 8bcdc378cf70..eb3ce3421465 100644
--- a/sys/compat/linux/linux_futex.c
+++ b/sys/compat/linux/linux_futex.c
@@ -56,6 +56,7 @@ __FBSDID("$FreeBSD$");
 #include <compat/linux/linux_util.h>
 
 #define        FUTEX_SHARED    0x8     /* shared futex */
+#define        FUTEX_UNOWNED   0
 
 #define        GET_SHARED(a)   (a->flags & FUTEX_SHARED) ? AUTO_SHARE : 
THREAD_SHARE
 
@@ -399,7 +400,7 @@ linux_futex_lock_pi(struct thread *td, bool try, struct 
linux_futex_args *args)
        umtxq_unlock(&uq->uq_key);
        for (;;) {
                /* Try uncontested case first. */
-               rv = casueword32(args->uaddr, 0, &owner, em->em_tid);
+               rv = casueword32(args->uaddr, FUTEX_UNOWNED, &owner, 
em->em_tid);
                /* The acquire succeeded. */
                if (rv == 0) {
                        error = 0;
@@ -414,7 +415,7 @@ linux_futex_lock_pi(struct thread *td, bool try, struct 
linux_futex_args *args)
                 * Nobody owns it, but the acquire failed. This can happen
                 * with ll/sc atomic.
                 */
-               if (owner == 0) {
+               if (owner == FUTEX_UNOWNED) {
                        error = thread_check_susp(td, true);
                        if (error != 0)
                                break;
@@ -441,7 +442,7 @@ linux_futex_lock_pi(struct thread *td, bool try, struct 
linux_futex_args *args)
                 * Futex owner died, handle_futex_death() set the OWNER_DIED bit
                 * and clear tid. Try to acquire it.
                 */
-               if ((owner & FUTEX_TID_MASK) == 0) {
+               if ((owner & FUTEX_TID_MASK) == FUTEX_UNOWNED) {
                        old_owner = owner;
                        owner = owner & (FUTEX_WAITERS | FUTEX_OWNER_DIED);
                        owner |= em->em_tid;
@@ -486,7 +487,7 @@ linux_futex_lock_pi(struct thread *td, bool try, struct 
linux_futex_args *args)
                 * Linux does some checks of futex state, we return EINVAL,
                 * as the user space can take care of this.
                 */
-               if ((owner & FUTEX_OWNER_DIED) != 0) {
+               if ((owner & FUTEX_OWNER_DIED) != FUTEX_UNOWNED) {
                        error = EINVAL;
                        break;
                }
@@ -608,7 +609,7 @@ linux_futex_unlock_pi(struct thread *td, bool rb, struct 
linux_futex_args *args)
        if (count > 1)
                new_owner = FUTEX_WAITERS;
        else
-               new_owner = 0;
+               new_owner = FUTEX_UNOWNED;
 
 again:
        error = casueword32(args->uaddr, owner, &old, new_owner);