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Commit 459f7923 authored by Stefan Richter's avatar Stefan Richter
Browse files

firewire: clean up fw_card reference counting 



This is a functionally equivalent replacement of the current reference
counting of struct fw_card instances.  It only converts it to common
idioms as suggested by Kristian Høgsberg:
  - struct kref replaces atomic_t as the counter.
  - wait_for_completion is used to wait for all card users to complete.

BTW, it may make sense to count card->flush_timer and card->work as
card users too.

Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent 2147ef20

drivers/firewire/fw-card.c

+20 −10
Original line number Diff line number Diff line
@@ -16,12 +16,15 @@ 
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 */



#include <linux/module.h>

#include <linux/errno.h>

#include <linux/completion.h>

#include <linux/crc-itu-t.h>

#include <linux/delay.h>

#include <linux/device.h>

#include <linux/errno.h>

#include <linux/kref.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/crc-itu-t.h>



#include "fw-transaction.h"

#include "fw-topology.h"

#include "fw-device.h"
@@ -396,7 +399,6 @@ fw_card_initialize(struct fw_card *card, const struct fw_card_driver *driver, 
{

	static atomic_t index = ATOMIC_INIT(-1);



	atomic_set(&card->device_count, 0);

	card->index = atomic_inc_return(&index);

	card->driver = driver;

	card->device = device;
@@ -405,6 +407,8 @@ fw_card_initialize(struct fw_card *card, const struct fw_card_driver *driver, 
	card->color = 0;

	card->broadcast_channel = BROADCAST_CHANNEL_INITIAL;



	kref_init(&card->kref);

	init_completion(&card->done);

	INIT_LIST_HEAD(&card->transaction_list);

	spin_lock_init(&card->lock);

	setup_timer(&card->flush_timer,
@@ -506,6 +510,14 @@ static struct fw_card_driver dummy_driver = { 
	.enable_phys_dma = dummy_enable_phys_dma,

};



void

fw_card_release(struct kref *kref)

{

	struct fw_card *card = container_of(kref, struct fw_card, kref);



	complete(&card->done);

}



void

fw_core_remove_card(struct fw_card *card)

{
@@ -521,12 +533,10 @@ fw_core_remove_card(struct fw_card *card) 
	card->driver = &dummy_driver;



	fw_destroy_nodes(card);

	/*

	 * Wait for all device workqueue jobs to finish.  Otherwise the

	 * firewire-core module could be unloaded before the jobs ran.

	 */

	while (atomic_read(&card->device_count) > 0)

		msleep(100);



	/* Wait for all users, especially device workqueue jobs, to finish. */

	fw_card_put(card);

	wait_for_completion(&card->done);



	cancel_delayed_work_sync(&card->work);

	fw_flush_transactions(card);

drivers/firewire/fw-device.c

+2 −3
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ static void fw_device_release(struct device *dev) 
	fw_node_put(device->node);

	kfree(device->config_rom);

	kfree(device);

	atomic_dec(&card->device_count);

	fw_card_put(card);

}



int fw_device_enable_phys_dma(struct fw_device *device)
@@ -946,8 +946,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event) 
		 */

		device_initialize(&device->device);

		atomic_set(&device->state, FW_DEVICE_INITIALIZING);

		atomic_inc(&card->device_count);

		device->card = card;

		device->card = fw_card_get(card);

		device->node = fw_node_get(node);

		device->node_id = node->node_id;

		device->generation = card->generation;

drivers/firewire/fw-transaction.h

+18 −2
Original line number Diff line number Diff line
@@ -19,14 +19,15 @@ 
#ifndef __fw_transaction_h

#define __fw_transaction_h



#include <linux/completion.h>

#include <linux/device.h>

#include <linux/dma-mapping.h>

#include <linux/firewire-constants.h>

#include <linux/kref.h>

#include <linux/list.h>

#include <linux/spinlock_types.h>

#include <linux/timer.h>

#include <linux/workqueue.h>

#include <asm/atomic.h>



#define TCODE_IS_READ_REQUEST(tcode)	(((tcode) & ~1) == 4)

#define TCODE_IS_BLOCK_PACKET(tcode)	(((tcode) &  1) != 0)
@@ -219,7 +220,8 @@ extern struct bus_type fw_bus_type; 
struct fw_card {

	const struct fw_card_driver *driver;

	struct device *device;

	atomic_t device_count;

	struct kref kref;

	struct completion done;



	int node_id;

	int generation;
@@ -260,6 +262,20 @@ struct fw_card { 
	int bm_generation;

};



static inline struct fw_card *fw_card_get(struct fw_card *card)

{

	kref_get(&card->kref);



	return card;

}



void fw_card_release(struct kref *kref);



static inline void fw_card_put(struct fw_card *card)

{

	kref_put(&card->kref, fw_card_release);

}



/*

 * The iso packet format allows for an immediate header/payload part

 * stored in 'header' immediately after the packet info plus an