From b247d47be1834b3dcd006128d52592acbcb0f010 Mon Sep 17 00:00:00 2001 From: Richard Yao Date: Tue, 13 Sep 2022 19:59:33 -0400 Subject: [PATCH] Cleanup: Make memory barrier definitions consistent across kernels We inherited membar_consumer() and membar_producer() from OpenSolaris, but we had replaced membar_consumer() with Linux's smp_rmb() in zfs_ioctl.c. The FreeBSD SPL consequently implemented a shim for the Linux-only smp_rmb(). We reinstate membar_consumer() in platform independent code and fix the FreeBSD SPL to implement membar_consumer() in a way analogous to Linux. Reviewed-by: Konstantin Belousov Reviewed-by: Mateusz Guzik Reviewed-by: Brian Behlendorf Reviewed-by: Neal Gompa Reviewed-by: Alexander Motin Signed-off-by: Richard Yao Closes #13843 --- include/os/freebsd/linux/compiler.h | 1 - include/os/freebsd/spl/sys/atomic.h | 3 ++- include/os/linux/spl/sys/vmsystm.h | 2 ++ module/zfs/zfs_ioctl.c | 2 +- 4 files changed, 5 insertions(+), 3 deletions(-) diff --git a/include/os/freebsd/linux/compiler.h b/include/os/freebsd/linux/compiler.h index 20903717b5..79f9b2d8a9 100644 --- a/include/os/freebsd/linux/compiler.h +++ b/include/os/freebsd/linux/compiler.h @@ -83,7 +83,6 @@ #define __printf(a, b) __printflike(a, b) #define barrier() __asm__ __volatile__("": : :"memory") -#define smp_rmb() rmb() #define ___PASTE(a, b) a##b #define __PASTE(a, b) ___PASTE(a, b) diff --git a/include/os/freebsd/spl/sys/atomic.h b/include/os/freebsd/spl/sys/atomic.h index 1a68bfc4de..01b13fc9af 100644 --- a/include/os/freebsd/spl/sys/atomic.h +++ b/include/os/freebsd/spl/sys/atomic.h @@ -57,7 +57,8 @@ extern uint64_t atomic_cas_64(volatile uint64_t *target, uint64_t cmp, uint64_t newval); #endif -#define membar_producer atomic_thread_fence_rel +#define membar_consumer() atomic_thread_fence_acq() +#define membar_producer() atomic_thread_fence_rel() static __inline uint32_t atomic_add_32_nv(volatile uint32_t *target, int32_t delta) diff --git a/include/os/linux/spl/sys/vmsystm.h b/include/os/linux/spl/sys/vmsystm.h index b3f121ecf0..fcd61e818f 100644 --- a/include/os/linux/spl/sys/vmsystm.h +++ b/include/os/linux/spl/sys/vmsystm.h @@ -44,7 +44,9 @@ #define zfs_totalhigh_pages totalhigh_pages #endif +#define membar_consumer() smp_rmb() #define membar_producer() smp_wmb() + #define physmem zfs_totalram_pages #define xcopyin(from, to, size) copy_from_user(to, from, size) diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c index 3d2492b9b9..4601ef5278 100644 --- a/module/zfs/zfs_ioctl.c +++ b/module/zfs/zfs_ioctl.c @@ -7398,7 +7398,7 @@ zfsdev_get_state_impl(minor_t minor, enum zfsdev_state_type which) for (zs = zfsdev_state_list; zs != NULL; zs = zs->zs_next) { if (zs->zs_minor == minor) { - smp_rmb(); + membar_consumer(); switch (which) { case ZST_ONEXIT: return (zs->zs_onexit);