1.\" $OpenBSD: SMR_PTR_GET.9,v 1.3 2019/07/05 04:46:26 dlg Exp $ 2.\" 3.\" Copyright (c) 2019 Visa Hankala 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: July 5 2019 $ 18.Dt SMR_PTR_GET 9 19.Os 20.Sh NAME 21.Nm SMR_PTR_GET , 22.Nm SMR_PTR_GET_LOCKED , 23.Nm SMR_PTR_SET_LOCKED 24.Nd safe memory reclamation pointer API 25.Sh SYNOPSIS 26.Ft TYPE 27.Fn SMR_PTR_GET "TYPE *pptr" 28.Ft TYPE 29.Fn SMR_PTR_GET_LOCKED "TYPE *pptr" 30.Ft void 31.Fn SMR_PTR_SET_LOCKED "TYPE *pptr" "TYPE v" 32.Sh DESCRIPTION 33The SMR_PTR macros are used for accessing SMR-protected pointers. 34.Pp 35The macro 36.Fn SMR_PTR_GET 37reads the pointer referenced by 38.Fa pptr 39for dereferencing inside SMR read-side critical section. 40.Pp 41.Fn SMR_PTR_GET_LOCKED 42reads the pointer referenced by 43.Fa pptr 44for dereferencing inside writer context. 45.Pp 46.Fn SMR_PTR_SET_LOCKED 47writes value 48.Fa v 49to the pointer referenced by 50.Fa pptr . 51The operation issues a write-write memory barrier with 52.Xr membar_producer 9 53before the pointer write. 54.Sh CONTEXT 55.Fn SMR_PTR_GET , 56.Fn SMR_PTR_GET_LOCKED 57and 58.Fn SMR_PTR_SET_LOCKED 59can be called during autoconf, from process context, or from interrupt context. 60.Pp 61.Fn SMR_PTR_GET 62can be used from SMR read-side critical section. 63.Fn SMR_PTR_GET_LOCKED 64and 65.Fn SMR_PTR_SET_LOCKED 66can be used from writer context. 67.Sh SEE ALSO 68.Xr membar_producer 9 , 69.Xr SMR_LIST_INIT 9 , 70.Xr smr_read_enter 9 71.Sh HISTORY 72The SMR_PTR macros first appeared in 73.Ox 6.5 . 74