kernel-ark/drivers/ieee1394/hosts.c
Ingo Molnar d378834840 [PATCH] lockdep: annotate ieee1394 skb-queue-head locking
ieee1394 reuses the skb infrastructure of the networking code, and uses two
skb-head queues: ->pending_packet_queue and hpsbpkt_queue.  The latter is used
in the usual fashion: processed from a kernel thread.  The other one,
->pending_packet_queue is also processed from hardirq context (f.e.  in
hpsb_bus_reset()), which is not what the networking code usually does (which
completes from softirq or process context).  This locking assymetry can be
totally correct if done carefully, but it can also be dangerous if networking
helper functions are reused, which could assume traditional networking use.

It would probably be more robust to push this completion into a workqueue -
but technically the code can be 100% correct, and lockdep has to be taught
about it.  The solution is to split the ->pending_packet_queue skb-head->lock
class from the networking lock-class by using a private lock-validator key.

Has no effect on non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Jody McIntyre <scjody@modernduck.com>
Cc: Ben Collins <bcollins@debian.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:08 -07:00

245 lines
6.1 KiB
C

/*
* IEEE 1394 for Linux
*
* Low level (host adapter) management.
*
* Copyright (C) 1999 Andreas E. Bombe
* Copyright (C) 1999 Emanuel Pirker
*
* This code is licensed under the GPL. See the file COPYING in the root
* directory of the kernel sources for details.
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/mutex.h>
#include "csr1212.h"
#include "ieee1394.h"
#include "ieee1394_types.h"
#include "hosts.h"
#include "ieee1394_core.h"
#include "highlevel.h"
#include "nodemgr.h"
#include "csr.h"
#include "config_roms.h"
static void delayed_reset_bus(void * __reset_info)
{
struct hpsb_host *host = (struct hpsb_host*)__reset_info;
int generation = host->csr.generation + 1;
/* The generation field rolls over to 2 rather than 0 per IEEE
* 1394a-2000. */
if (generation > 0xf || generation < 2)
generation = 2;
CSR_SET_BUS_INFO_GENERATION(host->csr.rom, generation);
if (csr1212_generate_csr_image(host->csr.rom) != CSR1212_SUCCESS) {
/* CSR image creation failed, reset generation field and do not
* issue a bus reset. */
CSR_SET_BUS_INFO_GENERATION(host->csr.rom, host->csr.generation);
return;
}
host->csr.generation = generation;
host->update_config_rom = 0;
if (host->driver->set_hw_config_rom)
host->driver->set_hw_config_rom(host, host->csr.rom->bus_info_data);
host->csr.gen_timestamp[host->csr.generation] = jiffies;
hpsb_reset_bus(host, SHORT_RESET);
}
static int dummy_transmit_packet(struct hpsb_host *h, struct hpsb_packet *p)
{
return 0;
}
static int dummy_devctl(struct hpsb_host *h, enum devctl_cmd c, int arg)
{
return -1;
}
static int dummy_isoctl(struct hpsb_iso *iso, enum isoctl_cmd command, unsigned long arg)
{
return -1;
}
static struct hpsb_host_driver dummy_driver = {
.transmit_packet = dummy_transmit_packet,
.devctl = dummy_devctl,
.isoctl = dummy_isoctl
};
static int alloc_hostnum_cb(struct hpsb_host *host, void *__data)
{
int *hostnum = __data;
if (host->id == *hostnum)
return 1;
return 0;
}
/**
* hpsb_alloc_host - allocate a new host controller.
* @drv: the driver that will manage the host controller
* @extra: number of extra bytes to allocate for the driver
*
* Allocate a &hpsb_host and initialize the general subsystem specific
* fields. If the driver needs to store per host data, as drivers
* usually do, the amount of memory required can be specified by the
* @extra parameter. Once allocated, the driver should initialize the
* driver specific parts, enable the controller and make it available
* to the general subsystem using hpsb_add_host().
*
* Return Value: a pointer to the &hpsb_host if successful, %NULL if
* no memory was available.
*/
static DEFINE_MUTEX(host_num_alloc);
/*
* The pending_packet_queue is special in that it's processed
* from hardirq context too (such as hpsb_bus_reset()). Hence
* split the lock class from the usual networking skb-head
* lock class by using a separate key for it:
*/
static struct lock_class_key pending_packet_queue_key;
struct hpsb_host *hpsb_alloc_host(struct hpsb_host_driver *drv, size_t extra,
struct device *dev)
{
struct hpsb_host *h;
int i;
int hostnum = 0;
h = kzalloc(sizeof(*h) + extra, SLAB_KERNEL);
if (!h)
return NULL;
h->csr.rom = csr1212_create_csr(&csr_bus_ops, CSR_BUS_INFO_SIZE, h);
if (!h->csr.rom) {
kfree(h);
return NULL;
}
h->hostdata = h + 1;
h->driver = drv;
skb_queue_head_init(&h->pending_packet_queue);
lockdep_set_class(&h->pending_packet_queue.lock,
&pending_packet_queue_key);
INIT_LIST_HEAD(&h->addr_space);
for (i = 2; i < 16; i++)
h->csr.gen_timestamp[i] = jiffies - 60 * HZ;
for (i = 0; i < ARRAY_SIZE(h->tpool); i++)
HPSB_TPOOL_INIT(&h->tpool[i]);
atomic_set(&h->generation, 0);
INIT_WORK(&h->delayed_reset, delayed_reset_bus, h);
init_timer(&h->timeout);
h->timeout.data = (unsigned long) h;
h->timeout.function = abort_timedouts;
h->timeout_interval = HZ / 20; // 50ms by default
h->topology_map = h->csr.topology_map + 3;
h->speed_map = (u8 *)(h->csr.speed_map + 2);
mutex_lock(&host_num_alloc);
while (nodemgr_for_each_host(&hostnum, alloc_hostnum_cb))
hostnum++;
h->id = hostnum;
memcpy(&h->device, &nodemgr_dev_template_host, sizeof(h->device));
h->device.parent = dev;
snprintf(h->device.bus_id, BUS_ID_SIZE, "fw-host%d", h->id);
h->class_dev.dev = &h->device;
h->class_dev.class = &hpsb_host_class;
snprintf(h->class_dev.class_id, BUS_ID_SIZE, "fw-host%d", h->id);
device_register(&h->device);
class_device_register(&h->class_dev);
get_device(&h->device);
mutex_unlock(&host_num_alloc);
return h;
}
int hpsb_add_host(struct hpsb_host *host)
{
if (hpsb_default_host_entry(host))
return -ENOMEM;
hpsb_add_extra_config_roms(host);
highlevel_add_host(host);
return 0;
}
void hpsb_remove_host(struct hpsb_host *host)
{
host->is_shutdown = 1;
cancel_delayed_work(&host->delayed_reset);
flush_scheduled_work();
host->driver = &dummy_driver;
highlevel_remove_host(host);
hpsb_remove_extra_config_roms(host);
class_device_unregister(&host->class_dev);
device_unregister(&host->device);
}
int hpsb_update_config_rom_image(struct hpsb_host *host)
{
unsigned long reset_delay;
int next_gen = host->csr.generation + 1;
if (!host->update_config_rom)
return -EINVAL;
if (next_gen > 0xf)
next_gen = 2;
/* Stop the delayed interrupt, we're about to change the config rom and
* it would be a waste to do a bus reset twice. */
cancel_delayed_work(&host->delayed_reset);
/* IEEE 1394a-2000 prohibits using the same generation number
* twice in a 60 second period. */
if (time_before(jiffies, host->csr.gen_timestamp[next_gen] + 60 * HZ))
/* Wait 60 seconds from the last time this generation number was
* used. */
reset_delay = (60 * HZ) + host->csr.gen_timestamp[next_gen] - jiffies;
else
/* Wait 1 second in case some other code wants to change the
* Config ROM in the near future. */
reset_delay = HZ;
PREPARE_WORK(&host->delayed_reset, delayed_reset_bus, host);
schedule_delayed_work(&host->delayed_reset, reset_delay);
return 0;
}