kernel-ark/net/irda/discovery.c
Arjan van de Ven 9a32144e9d [PATCH] mark struct file_operations const 7
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>
2007-02-12 09:48:46 -08:00

420 lines
12 KiB
C

/*********************************************************************
*
* Filename: discovery.c
* Version: 0.1
* Description: Routines for handling discoveries at the IrLMP layer
* Status: Experimental.
* Author: Dag Brattli <dagb@cs.uit.no>
* Created at: Tue Apr 6 15:33:50 1999
* Modified at: Sat Oct 9 17:11:31 1999
* Modified by: Dag Brattli <dagb@cs.uit.no>
* Modified at: Fri May 28 3:11 CST 1999
* Modified by: Horst von Brand <vonbrand@sleipnir.valparaiso.cl>
*
* Copyright (c) 1999 Dag Brattli, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* 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., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*
********************************************************************/
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <net/irda/irda.h>
#include <net/irda/irlmp.h>
#include <net/irda/discovery.h>
/*
* Function irlmp_add_discovery (cachelog, discovery)
*
* Add a new discovery to the cachelog, and remove any old discoveries
* from the same device
*
* Note : we try to preserve the time this device was *first* discovered
* (as opposed to the time of last discovery used for cleanup). This is
* used by clients waiting for discovery events to tell if the device
* discovered is "new" or just the same old one. They can't rely there
* on a binary flag (new/old), because not all discovery events are
* propagated to them, and they might not always listen, so they would
* miss some new devices popping up...
* Jean II
*/
void irlmp_add_discovery(hashbin_t *cachelog, discovery_t *new)
{
discovery_t *discovery, *node;
unsigned long flags;
/* Set time of first discovery if node is new (see below) */
new->firststamp = new->timestamp;
spin_lock_irqsave(&cachelog->hb_spinlock, flags);
/*
* Remove all discoveries of devices that has previously been
* discovered on the same link with the same name (info), or the
* same daddr. We do this since some devices (mostly PDAs) change
* their device address between every discovery.
*/
discovery = (discovery_t *) hashbin_get_first(cachelog);
while (discovery != NULL ) {
node = discovery;
/* Be sure to stay one item ahead */
discovery = (discovery_t *) hashbin_get_next(cachelog);
if ((node->data.saddr == new->data.saddr) &&
((node->data.daddr == new->data.daddr) ||
(strcmp(node->data.info, new->data.info) == 0)))
{
/* This discovery is a previous discovery
* from the same device, so just remove it
*/
hashbin_remove_this(cachelog, (irda_queue_t *) node);
/* Check if hints bits are unchanged */
if(u16ho(node->data.hints) == u16ho(new->data.hints))
/* Set time of first discovery for this node */
new->firststamp = node->firststamp;
kfree(node);
}
}
/* Insert the new and updated version */
hashbin_insert(cachelog, (irda_queue_t *) new, new->data.daddr, NULL);
spin_unlock_irqrestore(&cachelog->hb_spinlock, flags);
}
/*
* Function irlmp_add_discovery_log (cachelog, log)
*
* Merge a disovery log into the cachelog.
*
*/
void irlmp_add_discovery_log(hashbin_t *cachelog, hashbin_t *log)
{
discovery_t *discovery;
IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
/*
* If log is missing this means that IrLAP was unable to perform the
* discovery, so restart discovery again with just the half timeout
* of the normal one.
*/
/* Well... It means that there was nobody out there - Jean II */
if (log == NULL) {
/* irlmp_start_discovery_timer(irlmp, 150); */
return;
}
/*
* Locking : we are the only owner of this discovery log, so
* no need to lock it.
* We just need to lock the global log in irlmp_add_discovery().
*/
discovery = (discovery_t *) hashbin_remove_first(log);
while (discovery != NULL) {
irlmp_add_discovery(cachelog, discovery);
discovery = (discovery_t *) hashbin_remove_first(log);
}
/* Delete the now empty log */
hashbin_delete(log, (FREE_FUNC) kfree);
}
/*
* Function irlmp_expire_discoveries (log, saddr, force)
*
* Go through all discoveries and expire all that has stayed too long
*
* Note : this assume that IrLAP won't change its saddr, which
* currently is a valid assumption...
*/
void irlmp_expire_discoveries(hashbin_t *log, __u32 saddr, int force)
{
discovery_t * discovery;
discovery_t * curr;
unsigned long flags;
discinfo_t * buffer = NULL;
int n; /* Size of the full log */
int i = 0; /* How many we expired */
IRDA_ASSERT(log != NULL, return;);
IRDA_DEBUG(4, "%s()\n", __FUNCTION__);
spin_lock_irqsave(&log->hb_spinlock, flags);
discovery = (discovery_t *) hashbin_get_first(log);
while (discovery != NULL) {
/* Be sure to be one item ahead */
curr = discovery;
discovery = (discovery_t *) hashbin_get_next(log);
/* Test if it's time to expire this discovery */
if ((curr->data.saddr == saddr) &&
(force ||
((jiffies - curr->timestamp) > DISCOVERY_EXPIRE_TIMEOUT)))
{
/* Create buffer as needed.
* As this function get called a lot and most time
* we don't have anything to put in the log (we are
* quite picky), we can save a lot of overhead
* by not calling kmalloc. Jean II */
if(buffer == NULL) {
/* Create the client specific buffer */
n = HASHBIN_GET_SIZE(log);
buffer = kmalloc(n * sizeof(struct irda_device_info), GFP_ATOMIC);
if (buffer == NULL) {
spin_unlock_irqrestore(&log->hb_spinlock, flags);
return;
}
}
/* Copy discovery information */
memcpy(&(buffer[i]), &(curr->data),
sizeof(discinfo_t));
i++;
/* Remove it from the log */
curr = hashbin_remove_this(log, (irda_queue_t *) curr);
kfree(curr);
}
}
/* Drop the spinlock before calling the higher layers, as
* we can't guarantee they won't call us back and create a
* deadlock. We will work on our own private data, so we
* don't care to be interupted. - Jean II */
spin_unlock_irqrestore(&log->hb_spinlock, flags);
if(buffer == NULL)
return;
/* Tell IrLMP and registered clients about it */
irlmp_discovery_expiry(buffer, i);
/* Free up our buffer */
kfree(buffer);
}
#if 0
/*
* Function irlmp_dump_discoveries (log)
*
* Print out all discoveries in log
*
*/
void irlmp_dump_discoveries(hashbin_t *log)
{
discovery_t *discovery;
IRDA_ASSERT(log != NULL, return;);
discovery = (discovery_t *) hashbin_get_first(log);
while (discovery != NULL) {
IRDA_DEBUG(0, "Discovery:\n");
IRDA_DEBUG(0, " daddr=%08x\n", discovery->data.daddr);
IRDA_DEBUG(0, " saddr=%08x\n", discovery->data.saddr);
IRDA_DEBUG(0, " nickname=%s\n", discovery->data.info);
discovery = (discovery_t *) hashbin_get_next(log);
}
}
#endif
/*
* Function irlmp_copy_discoveries (log, pn, mask)
*
* Copy all discoveries in a buffer
*
* This function implement a safe way for lmp clients to access the
* discovery log. The basic problem is that we don't want the log
* to change (add/remove) while the client is reading it. If the
* lmp client manipulate directly the hashbin, he is sure to get
* into troubles...
* The idea is that we copy all the current discovery log in a buffer
* which is specific to the client and pass this copy to him. As we
* do this operation with the spinlock grabbed, we are safe...
* Note : we don't want those clients to grab the spinlock, because
* we have no control on how long they will hold it...
* Note : we choose to copy the log in "struct irda_device_info" to
* save space...
* Note : the client must kfree himself() the log...
* Jean II
*/
struct irda_device_info *irlmp_copy_discoveries(hashbin_t *log, int *pn,
__u16 mask, int old_entries)
{
discovery_t * discovery;
unsigned long flags;
discinfo_t * buffer = NULL;
int j_timeout = (sysctl_discovery_timeout * HZ);
int n; /* Size of the full log */
int i = 0; /* How many we picked */
IRDA_ASSERT(pn != NULL, return NULL;);
IRDA_ASSERT(log != NULL, return NULL;);
/* Save spin lock */
spin_lock_irqsave(&log->hb_spinlock, flags);
discovery = (discovery_t *) hashbin_get_first(log);
while (discovery != NULL) {
/* Mask out the ones we don't want :
* We want to match the discovery mask, and to get only
* the most recent one (unless we want old ones) */
if ((u16ho(discovery->data.hints) & mask) &&
((old_entries) ||
((jiffies - discovery->firststamp) < j_timeout)) ) {
/* Create buffer as needed.
* As this function get called a lot and most time
* we don't have anything to put in the log (we are
* quite picky), we can save a lot of overhead
* by not calling kmalloc. Jean II */
if(buffer == NULL) {
/* Create the client specific buffer */
n = HASHBIN_GET_SIZE(log);
buffer = kmalloc(n * sizeof(struct irda_device_info), GFP_ATOMIC);
if (buffer == NULL) {
spin_unlock_irqrestore(&log->hb_spinlock, flags);
return NULL;
}
}
/* Copy discovery information */
memcpy(&(buffer[i]), &(discovery->data),
sizeof(discinfo_t));
i++;
}
discovery = (discovery_t *) hashbin_get_next(log);
}
spin_unlock_irqrestore(&log->hb_spinlock, flags);
/* Get the actual number of device in the buffer and return */
*pn = i;
return(buffer);
}
#ifdef CONFIG_PROC_FS
static inline discovery_t *discovery_seq_idx(loff_t pos)
{
discovery_t *discovery;
for (discovery = (discovery_t *) hashbin_get_first(irlmp->cachelog);
discovery != NULL;
discovery = (discovery_t *) hashbin_get_next(irlmp->cachelog)) {
if (pos-- == 0)
break;
}
return discovery;
}
static void *discovery_seq_start(struct seq_file *seq, loff_t *pos)
{
spin_lock_irq(&irlmp->cachelog->hb_spinlock);
return *pos ? discovery_seq_idx(*pos - 1) : SEQ_START_TOKEN;
}
static void *discovery_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
++*pos;
return (v == SEQ_START_TOKEN)
? (void *) hashbin_get_first(irlmp->cachelog)
: (void *) hashbin_get_next(irlmp->cachelog);
}
static void discovery_seq_stop(struct seq_file *seq, void *v)
{
spin_unlock_irq(&irlmp->cachelog->hb_spinlock);
}
static int discovery_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN)
seq_puts(seq, "IrLMP: Discovery log:\n\n");
else {
const discovery_t *discovery = v;
seq_printf(seq, "nickname: %s, hint: 0x%02x%02x",
discovery->data.info,
discovery->data.hints[0],
discovery->data.hints[1]);
#if 0
if ( discovery->data.hints[0] & HINT_PNP)
seq_puts(seq, "PnP Compatible ");
if ( discovery->data.hints[0] & HINT_PDA)
seq_puts(seq, "PDA/Palmtop ");
if ( discovery->data.hints[0] & HINT_COMPUTER)
seq_puts(seq, "Computer ");
if ( discovery->data.hints[0] & HINT_PRINTER)
seq_puts(seq, "Printer ");
if ( discovery->data.hints[0] & HINT_MODEM)
seq_puts(seq, "Modem ");
if ( discovery->data.hints[0] & HINT_FAX)
seq_puts(seq, "Fax ");
if ( discovery->data.hints[0] & HINT_LAN)
seq_puts(seq, "LAN Access ");
if ( discovery->data.hints[1] & HINT_TELEPHONY)
seq_puts(seq, "Telephony ");
if ( discovery->data.hints[1] & HINT_FILE_SERVER)
seq_puts(seq, "File Server ");
if ( discovery->data.hints[1] & HINT_COMM)
seq_puts(seq, "IrCOMM ");
if ( discovery->data.hints[1] & HINT_OBEX)
seq_puts(seq, "IrOBEX ");
#endif
seq_printf(seq,", saddr: 0x%08x, daddr: 0x%08x\n\n",
discovery->data.saddr,
discovery->data.daddr);
seq_putc(seq, '\n');
}
return 0;
}
static struct seq_operations discovery_seq_ops = {
.start = discovery_seq_start,
.next = discovery_seq_next,
.stop = discovery_seq_stop,
.show = discovery_seq_show,
};
static int discovery_seq_open(struct inode *inode, struct file *file)
{
IRDA_ASSERT(irlmp != NULL, return -EINVAL;);
return seq_open(file, &discovery_seq_ops);
}
const struct file_operations discovery_seq_fops = {
.owner = THIS_MODULE,
.open = discovery_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#endif