pm24.git/kernel/futex, branch v5.16

futex: Fix PREEMPT_RT build

2021-10-19T15:27:05Z

Mike reported that rcuwait went walk-about and is causing failures on the PREEMPT_RT builds, restore it. Reported-by: Mike Galbraith Signed-off-by: Peter Zijlstra (Intel)

futex: Implement sys_futex_waitv()

2021-10-07T11:51:11Z

Add support to wait on multiple futexes. This is the interface implemented by this syscall: futex_waitv(struct futex_waitv *waiters, unsigned int nr_futexes, unsigned int flags, struct timespec *timeout, clockid_t clockid) struct futex_waitv { __u64 val; __u64 uaddr; __u32 flags; __u32 __reserved; }; Given an array of struct futex_waitv, wait on each uaddr. The thread wakes if a futex_wake() is performed at any uaddr. The syscall returns immediately if any waiter has *uaddr != val. *timeout is an optional absolute timeout value for the operation. This syscall supports only 64bit sized timeout structs. The flags argument of the syscall should be empty, but it can be used for future extensions. Flags for shared futexes, sizes, etc. should be used on the individual flags of each waiter. __reserved is used for explicit padding and should be 0, but it might be used for future extensions. If the userspace uses 32-bit pointers, it should make sure to explicitly cast it when assigning to waitv::uaddr. Returns the array index of one of the woken futexes. There’s no given information of how many were woken, or any particular attribute of it (if it’s the first woken, if it is of the smaller index...). Signed-off-by: André Almeida Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210923171111.300673-17-andrealmeid@collabora.com

futex: Simplify double_lock_hb()

2021-10-07T11:51:11Z

We need to make sure that all requeue operations take the hash bucket locks in the same order to avoid deadlock. Simplify the current double_lock_hb implementation by making sure hb1 is always the "smallest" bucket to avoid extra checks. [André: Add commit description] Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: André Almeida Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://lore.kernel.org/r/20210923171111.300673-16-andrealmeid@collabora.com

futex: Split out wait/wake

2021-10-07T11:51:11Z

Move the wait/wake bits into their own file. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: André Almeida Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://lore.kernel.org/r/20210923171111.300673-15-andrealmeid@collabora.com

futex: Split out requeue

2021-10-07T11:51:10Z

Move all the requeue bits into their own file. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: André Almeida Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://lore.kernel.org/r/20210923171111.300673-14-andrealmeid@collabora.com

futex: Rename mark_wake_futex()

2021-10-07T11:51:10Z

In order to prepare introducing these symbols into the global namespace; rename: s/mark_wake_futex/futex_wake_mark/g Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: André Almeida Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://lore.kernel.org/r/20210923171111.300673-13-andrealmeid@collabora.com

futex: Rename: match_futex()

2021-10-07T11:51:10Z

In order to prepare introducing these symbols into the global namespace; rename: s/match_futex/futex_match/g Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: André Almeida Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://lore.kernel.org/r/20210923171111.300673-12-andrealmeid@collabora.com

futex: Rename: hb_waiter_{inc,dec,pending}()

2021-10-07T11:51:09Z

In order to prepare introducing these symbols into the global namespace; rename them: s/hb_waiters_/futex_&/g Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: André Almeida Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://lore.kernel.org/r/20210923171111.300673-11-andrealmeid@collabora.com

futex: Split out PI futex

2021-10-07T11:51:09Z

Move the PI futex implementation into it's own file. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: André Almeida Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://lore.kernel.org/r/20210923171111.300673-10-andrealmeid@collabora.com

futex: Rename: {get,cmpxchg}_futex_value_locked()

2021-10-07T11:51:09Z

In order to prepare introducing these symbols into the global namespace; rename them: s/\<\([^_ ]*\)_futex_value_locked/futex_\1_value_locked/g Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: André Almeida Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: André Almeida Link: https://lore.kernel.org/r/20210923171111.300673-9-andrealmeid@collabora.com