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net/wimax/id-table.c
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/* * Linux WiMAX * Mappping of generic netlink family IDs to net devices * * * Copyright (C) 2005-2006 Intel Corporation <linux-wimax@intel.com> * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version * 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301, USA. * * * We assign a single generic netlink family ID to each device (to * simplify lookup). * * We need a way to map family ID to a wimax_dev pointer. * * The idea is to use a very simple lookup. Using a netlink attribute * with (for example) the interface name implies a heavier search over * all the network devices; seemed kind of a waste given that we know * we are looking for a WiMAX device and that most systems will have * just a single WiMAX adapter. * * We put all the WiMAX devices in the system in a linked list and * match the generic link family ID against the list. * * By using a linked list, the case of a single adapter in the system * becomes (almost) no overhead, while still working for many more. If * it ever goes beyond two, I'll be surprised. */ #include <linux/device.h> #include <net/genetlink.h> #include <linux/netdevice.h> #include <linux/list.h> #include <linux/wimax.h> #include "wimax-internal.h" #define D_SUBMODULE id_table #include "debug-levels.h" static DEFINE_SPINLOCK(wimax_id_table_lock); static struct list_head wimax_id_table = LIST_HEAD_INIT(wimax_id_table); /* * wimax_id_table_add - add a gennetlink familiy ID / wimax_dev mapping * * @wimax_dev: WiMAX device descriptor to associate to the Generic * Netlink family ID. * * Look for an empty spot in the ID table; if none found, double the * table's size and get the first spot. */ void wimax_id_table_add(struct wimax_dev *wimax_dev) { d_fnstart(3, NULL, "(wimax_dev %p) ", wimax_dev); spin_lock(&wimax_id_table_lock); list_add(&wimax_dev->id_table_node, &wimax_id_table); spin_unlock(&wimax_id_table_lock); d_fnend(3, NULL, "(wimax_dev %p) ", wimax_dev); } /* * wimax_get_netdev_by_info - lookup a wimax_dev from the gennetlink info * * The generic netlink family ID has been filled out in the * nlmsghdr->nlmsg_type field, so we pull it from there, look it up in * the mapping table and reference the wimax_dev. * * When done, the reference should be dropped with * 'dev_put(wimax_dev->net_dev)'. */ struct wimax_dev *wimax_dev_get_by_genl_info( struct genl_info *info, int ifindex) { struct wimax_dev *wimax_dev = NULL; d_fnstart(3, NULL, "(info %p ifindex %d) ", info, ifindex); spin_lock(&wimax_id_table_lock); list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) { if (wimax_dev->net_dev->ifindex == ifindex) { dev_hold(wimax_dev->net_dev); |
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} } |
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wimax_dev = NULL; d_printf(1, NULL, "wimax: no devices found with ifindex %d ", ifindex); found: |
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spin_unlock(&wimax_id_table_lock); d_fnend(3, NULL, "(info %p ifindex %d) = %p ", info, ifindex, wimax_dev); return wimax_dev; } /* * wimax_id_table_rm - Remove a gennetlink familiy ID / wimax_dev mapping * * @id: family ID to remove from the table */ void wimax_id_table_rm(struct wimax_dev *wimax_dev) { spin_lock(&wimax_id_table_lock); list_del_init(&wimax_dev->id_table_node); spin_unlock(&wimax_id_table_lock); } /* * Release the gennetlink family id / mapping table * |
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* On debug, verify that the table is empty upon removal. We want the * code always compiled, to ensure it doesn't bit rot. It will be * compiled out if CONFIG_BUG is disabled. |
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*/ void wimax_id_table_release(void) { |
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struct wimax_dev *wimax_dev; |
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#ifndef CONFIG_BUG return; #endif |
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spin_lock(&wimax_id_table_lock); list_for_each_entry(wimax_dev, &wimax_id_table, id_table_node) { |
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pr_err("BUG: %s wimax_dev %p ifindex %d not cleared ", |
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__func__, wimax_dev, wimax_dev->net_dev->ifindex); WARN_ON(1); } spin_unlock(&wimax_id_table_lock); } |