linux/drivers/ieee1394/hosts.c
Stefan Richter 9951903e61 ieee1394: shrink tlabel pools, remove tpool semaphores
This patch reduces the size of struct hpsb_host and also removes
semaphores from ieee1394_transactions.c.  On i386, struct hpsb_host
shrinks from 10656 bytes to 6688 bytes.  This is accomplished by
 - using a single wait_queue for hpsb_get_tlabel instead of many
   instances of semaphores,
 - using a single lock to serialize access to all tlabel pools (the
   protected code regions are small, i.e. lock contention very low),
 - omitting the sysfs attribute tlabels_allocations.

Drawback:  In the rare case that a process needs to sleep because all
transaction labels for the node are temporarily exhausted, it is also
woken up if a tlabel for a different node became free, checks for an
available tlabel, and is put to sleep again.  The check is not costly
and the situation occurs extremely rarely.  (Tlabels are typically
only exhausted if there was no context switch to the khpsbpkt thread
which recycles tlables.)  Therefore the benefit of reduced tpool size
outweighs this drawback.

The sysfs attributes tlabels_free and tlabels_mask are not compiled
anymore unless CONFIG_IEEE1394_VERBOSEDEBUG is set.

The by far biggest member of struct hpsb_host, the struct csr_control
csr (5272 bytes on i386), is now placed at the end of struct hpsb_host.

Note, hpsb_get_tlabel calls the macro wait_event_interruptible with a
condition argument which has a side effect (allocation of a tlabel and
manipulation of the packet).  This side effect happens only if the
condition is true.  The patch relies on wait_event_interruptible not
evaluating the condition again after it became true.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2006-09-17 19:17:13 +02:00

241 lines
6 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;
}
/*
* 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;
static DEFINE_MUTEX(host_num_alloc);
/**
* 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.
*/
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;
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;
}