1.\" 2.\" Copyright (c) 2012 Vishesh Yadav 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. The name of the author may not be used to endorse or promote products 14.\" derived from this software without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd March 16, 2019 28.Dt IDR 9 29.Os 30.Sh NAME 31.Nm idr , 32.Nm idr_destroy , 33.Nm idr_find , 34.Nm idr_for_each , 35.Nm idr_get_new , 36.Nm idr_get_new_above , 37.Nm idr_init , 38.Nm idr_pre_get , 39.Nm idr_remove , 40.Nm idr_remove_all , 41.Nm idr_replace 42.Nd integer ID management library 43.Sh SYNOPSIS 44.In sys/idr.h 45.Ft void 46.Fn idr_destroy "struct idr *idp" 47.Ft void * 48.Fn idr_find "struct idr *idp" "int id" 49.Ft int 50.Fn idr_for_each "struct idr *idp" "int (*fn)(int id, void *p, void *data)" "void *data" 51.Ft int 52.Fn idr_get_new "struct idr *idp" "void *ptr" "int *id" 53.Ft int 54.Fn idr_get_new_above "struct idr *idp" "void *ptr" "int sid" "int *id" 55.Ft void 56.Fn idr_init "struct idr *idp" 57.Ft int 58.Fn idr_pre_get "struct idr *idp" "unsigned gfp_mask" 59.Ft void * 60.Fn idr_remove "struct idr *idp" "int id" 61.Ft void 62.Fn idr_remove_all "struct idr *idp" 63.Ft void * 64.Fn idr_replace "struct idr *idp" "void *ptr" "int id" 65.Sh DESCRIPTION 66The 67.Fn idr_init 68function initialize an 69.Nm 70handle that will be used by other functions of this API. 71.Pp 72The 73.Fn idr_destroy 74function frees all resources taken by the specified 75.Nm 76handle 77.Fa idp . 78.Pp 79The 80.Fn idr_find 81function returns the data pointer that is mapped with the specified 82.Fa id . 83.Pp 84The 85.Fn idr_for_each 86function iterates through all pointers registered with the specified 87.Nm 88handle 89.Fa idp 90and calls the callback function 91.Fn fn 92for each pointer. 93It is not safe to modify the 94.Nm 95tree through the callback function. 96If the callback function returns a non-zero integer, it stops and returns the 97value. 98.Pp 99The 100.Fn idr_get_new 101and 102.Fn idr_get_new_above 103functions allocate a new integer mapped with the specified pointer 104.Fa ptr . 105The new ID will be stored in 106.Fa id . 107If the tree becomes full, these functions will return 108.Fl Ns Er EAGAIN . 109In this case, 110.Fn idr_pre_get 111should be called to grow the tree. 112.Pp 113The 114.Fn idr_pre_get 115function should be called prior to calling 116.Fn idr_get_new 117and 118.Fn idr_get_new_above 119and preallocates enough memory for subsequent calls to these functions. 120It should be called without any locks held and returns 1 if enough memory 121was successfully allocated, otherwise 0. 122The 123.Fa gfp_mask 124is only present for compatibility with the Linux implementation of 125this API and is unused on 126.Dx . 127.Pp 128The 129.Fn idr_remove 130function removes the specified 131.Fa id 132from the tree, returning its pointer. 133NULL is returned if the id could not be found. 134.Pp 135The 136.Fn idr_remove_all 137function removes all entries in the 138.Nm 139tree 140.Fa idp . 141.Pp 142The 143.Fn idr_replace 144function replaces the pointer for the specified 145.Fa id 146with the new pointer 147.Fa ptr . 148It returns 149.Dv NULL 150if the id is not found. 151This behavior is different from the Linux API, which returns ERR_PTR(-ENOENT) 152if the id could not be found. 153