Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
297 lines
6.3 KiB
C
297 lines
6.3 KiB
C
/*
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* Linux NET3: Multicast List maintenance.
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*
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* Authors:
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* Tim Kordas <tjk@nostromo.eeap.cwru.edu>
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* Richard Underwood <richard@wuzz.demon.co.uk>
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*
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* Stir fried together from the IP multicast and CAP patches above
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* Alan Cox <Alan.Cox@linux.org>
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*
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* Fixes:
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* Alan Cox : Update the device on a real delete
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* rather than any time but...
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* Alan Cox : IFF_ALLMULTI support.
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* Alan Cox : New format set_multicast_list() calls.
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* Gleb Natapov : Remove dev_mc_lock.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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#include <linux/bitops.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/socket.h>
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#include <linux/sockios.h>
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#include <linux/in.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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#include <linux/if_ether.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/init.h>
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#include <net/ip.h>
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#include <net/route.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/arp.h>
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/*
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* Device multicast list maintenance.
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*
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* This is used both by IP and by the user level maintenance functions.
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* Unlike BSD we maintain a usage count on a given multicast address so
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* that a casual user application can add/delete multicasts used by
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* protocols without doing damage to the protocols when it deletes the
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* entries. It also helps IP as it tracks overlapping maps.
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*
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* Device mc lists are changed by bh at least if IPv6 is enabled,
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* so that it must be bh protected.
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*
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* We block accesses to device mc filters with netif_tx_lock.
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*/
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/*
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* Update the multicast list into the physical NIC controller.
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*/
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static void __dev_mc_upload(struct net_device *dev)
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{
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/* Don't do anything till we up the interface
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* [dev_open will call this function so the list will
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* stay sane]
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*/
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if (!(dev->flags&IFF_UP))
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return;
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/*
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* Devices with no set multicast or which have been
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* detached don't get set.
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*/
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if (dev->set_multicast_list == NULL ||
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!netif_device_present(dev))
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return;
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dev->set_multicast_list(dev);
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}
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void dev_mc_upload(struct net_device *dev)
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{
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netif_tx_lock_bh(dev);
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__dev_mc_upload(dev);
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netif_tx_unlock_bh(dev);
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}
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/*
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* Delete a device level multicast
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*/
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int dev_mc_delete(struct net_device *dev, void *addr, int alen, int glbl)
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{
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int err = 0;
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struct dev_mc_list *dmi, **dmip;
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netif_tx_lock_bh(dev);
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for (dmip = &dev->mc_list; (dmi = *dmip) != NULL; dmip = &dmi->next) {
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/*
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* Find the entry we want to delete. The device could
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* have variable length entries so check these too.
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*/
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if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
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alen == dmi->dmi_addrlen) {
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if (glbl) {
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int old_glbl = dmi->dmi_gusers;
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dmi->dmi_gusers = 0;
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if (old_glbl == 0)
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break;
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}
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if (--dmi->dmi_users)
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goto done;
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/*
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* Last user. So delete the entry.
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*/
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*dmip = dmi->next;
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dev->mc_count--;
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kfree(dmi);
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/*
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* We have altered the list, so the card
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* loaded filter is now wrong. Fix it
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*/
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__dev_mc_upload(dev);
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netif_tx_unlock_bh(dev);
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return 0;
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}
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}
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err = -ENOENT;
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done:
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netif_tx_unlock_bh(dev);
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return err;
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}
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/*
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* Add a device level multicast
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*/
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int dev_mc_add(struct net_device *dev, void *addr, int alen, int glbl)
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{
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int err = 0;
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struct dev_mc_list *dmi, *dmi1;
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dmi1 = kmalloc(sizeof(*dmi), GFP_ATOMIC);
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netif_tx_lock_bh(dev);
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for (dmi = dev->mc_list; dmi != NULL; dmi = dmi->next) {
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if (memcmp(dmi->dmi_addr, addr, dmi->dmi_addrlen) == 0 &&
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dmi->dmi_addrlen == alen) {
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if (glbl) {
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int old_glbl = dmi->dmi_gusers;
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dmi->dmi_gusers = 1;
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if (old_glbl)
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goto done;
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}
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dmi->dmi_users++;
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goto done;
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}
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}
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if ((dmi = dmi1) == NULL) {
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netif_tx_unlock_bh(dev);
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return -ENOMEM;
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}
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memcpy(dmi->dmi_addr, addr, alen);
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dmi->dmi_addrlen = alen;
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dmi->next = dev->mc_list;
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dmi->dmi_users = 1;
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dmi->dmi_gusers = glbl ? 1 : 0;
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dev->mc_list = dmi;
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dev->mc_count++;
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__dev_mc_upload(dev);
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netif_tx_unlock_bh(dev);
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return 0;
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done:
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netif_tx_unlock_bh(dev);
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kfree(dmi1);
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return err;
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}
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/*
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* Discard multicast list when a device is downed
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*/
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void dev_mc_discard(struct net_device *dev)
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{
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netif_tx_lock_bh(dev);
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while (dev->mc_list != NULL) {
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struct dev_mc_list *tmp = dev->mc_list;
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dev->mc_list = tmp->next;
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if (tmp->dmi_users > tmp->dmi_gusers)
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printk("dev_mc_discard: multicast leakage! dmi_users=%d\n", tmp->dmi_users);
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kfree(tmp);
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}
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dev->mc_count = 0;
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netif_tx_unlock_bh(dev);
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}
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#ifdef CONFIG_PROC_FS
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static void *dev_mc_seq_start(struct seq_file *seq, loff_t *pos)
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{
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struct net_device *dev;
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loff_t off = 0;
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read_lock(&dev_base_lock);
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for (dev = dev_base; dev; dev = dev->next) {
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if (off++ == *pos)
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return dev;
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}
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return NULL;
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}
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static void *dev_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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{
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struct net_device *dev = v;
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++*pos;
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return dev->next;
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}
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static void dev_mc_seq_stop(struct seq_file *seq, void *v)
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{
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read_unlock(&dev_base_lock);
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}
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static int dev_mc_seq_show(struct seq_file *seq, void *v)
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{
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struct dev_mc_list *m;
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struct net_device *dev = v;
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netif_tx_lock_bh(dev);
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for (m = dev->mc_list; m; m = m->next) {
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int i;
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seq_printf(seq, "%-4d %-15s %-5d %-5d ", dev->ifindex,
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dev->name, m->dmi_users, m->dmi_gusers);
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for (i = 0; i < m->dmi_addrlen; i++)
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seq_printf(seq, "%02x", m->dmi_addr[i]);
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seq_putc(seq, '\n');
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}
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netif_tx_unlock_bh(dev);
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return 0;
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}
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static struct seq_operations dev_mc_seq_ops = {
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.start = dev_mc_seq_start,
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.next = dev_mc_seq_next,
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.stop = dev_mc_seq_stop,
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.show = dev_mc_seq_show,
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};
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static int dev_mc_seq_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &dev_mc_seq_ops);
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}
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static const struct file_operations dev_mc_seq_fops = {
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.owner = THIS_MODULE,
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.open = dev_mc_seq_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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#endif
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void __init dev_mcast_init(void)
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{
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proc_net_fops_create("dev_mcast", 0, &dev_mc_seq_fops);
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}
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EXPORT_SYMBOL(dev_mc_add);
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EXPORT_SYMBOL(dev_mc_delete);
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EXPORT_SYMBOL(dev_mc_upload);
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