From 760e6f7befbab9a84c54457a8ee45313b7b91ee5 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 10 Jul 2025 13:00:09 +0200 Subject: futex: Remove support for IMMUTABLE The FH_FLAG_IMMUTABLE flag was meant to avoid the reference counting on the private hash and so to avoid the performance regression on big machines. With the switch to per-CPU counter this is no longer needed. That flag was never useable on any released kernel. Remove any support for IMMUTABLE while preserve the flags argument and enforce it to be zero. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20250710110011.384614-5-bigeasy@linutronix.de --- include/uapi/linux/prctl.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 43dec6eed559..3b93fb906e3c 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -367,8 +367,6 @@ struct prctl_mm_map { /* FUTEX hash management */ #define PR_FUTEX_HASH 78 # define PR_FUTEX_HASH_SET_SLOTS 1 -# define FH_FLAG_IMMUTABLE (1ULL << 0) # define PR_FUTEX_HASH_GET_SLOTS 2 -# define PR_FUTEX_HASH_GET_IMMUTABLE 3 #endif /* _LINUX_PRCTL_H */ -- cgit v1.2.3