[PATCH 1/7] futex: abstract out futex_op_to_flags() helper

Jens Axboe
2023-07-12T00:47:19Z

Rather than needing to duplicate this for the io_uring hook of futexes,
abstract out a helper.

No functional changes intended in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
kernel/futex/futex.h | 15 +++++++++++++++
kernel/futex/syscalls.c | 11 ++---------
2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h
index b5379c0e6d6d..d2949fca37d1 100644
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -291,4 +291,19 @@ extern int futex_unlock_pi(u32 __user *uaddr, unsigned int flags);

extern int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int trylock);

+static inline bool futex_op_to_flags(int op, int cmd, unsigned int *flags)
+{
+ if (!(op & FUTEX_PRIVATE_FLAG))
+ *flags |= FLAGS_SHARED;
+
+ if (op & FUTEX_CLOCK_REALTIME) {
+ *flags |= FLAGS_CLOCKRT;
+ if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
+ cmd != FUTEX_LOCK_PI2)
+ return false;
+ }
+
+ return true;
+}
+
#endif /* _FUTEX_H */
diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c
index a8074079b09e..75ca8c41cc94 100644
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -88,15 +88,8 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
int cmd = op & FUTEX_CMD_MASK;
unsigned int flags = 0;

- if (!(op & FUTEX_PRIVATE_FLAG))
- flags |= FLAGS_SHARED;
-
- if (op & FUTEX_CLOCK_REALTIME) {
- flags |= FLAGS_CLOCKRT;
- if (cmd != FUTEX_WAIT_BITSET && cmd != FUTEX_WAIT_REQUEUE_PI &&
- cmd != FUTEX_LOCK_PI2)
- return -ENOSYS;
- }
+ if (!futex_op_to_flags(op, cmd, &flags))
+ return -ENOSYS;

switch (cmd) {
case FUTEX_WAIT:
--
2.40.1