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Commit cf417e54 authored by Jay Fenlason's avatar Jay Fenlason Committed by Stefan Richter
Browse files

firewire: add a client_list_lock 



This adds a client_list_lock, which only protects the device's
client_list, so that future versions of the driver can call code that
takes the card->lock while holding the client_list_lock.  Adding this
lock is much simpler than adding __ versions of all the functions that
the future version may need.  The one ordering issue is to make sure
code never takes the client_list_lock with card->lock held.  Since
client_list_lock is only used in three places, that isn't hard.

Signed-off-by: default avatarJay Fenlason <fenlason@redhat.com>

Update fill_bus_reset_event() accordingly.  Include linux/spinlock.h.

Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent 1aa292bb

drivers/firewire/fw-cdev.c

+13 −15
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/poll.h>

#include <linux/preempt.h>

#include <linux/time.h>

#include <linux/spinlock.h>

#include <linux/delay.h>

#include <linux/mm.h>

#include <linux/idr.h>
@@ -132,9 +133,9 @@ static int fw_device_op_open(struct inode *inode, struct file *file) 


	file->private_data = client;



	spin_lock_irqsave(&device->card->lock, flags);

	spin_lock_irqsave(&device->client_list_lock, flags);

	list_add_tail(&client->link, &device->client_list);

	spin_unlock_irqrestore(&device->card->lock, flags);

	spin_unlock_irqrestore(&device->client_list_lock, flags);



	return 0;

}
@@ -205,12 +206,14 @@ fw_device_op_read(struct file *file, 
	return dequeue_event(client, buffer, count);

}



/* caller must hold card->lock so that node pointers can be dereferenced here */

static void

fill_bus_reset_event(struct fw_cdev_event_bus_reset *event,

		     struct client *client)

{

	struct fw_card *card = client->device->card;

	unsigned long flags;



	spin_lock_irqsave(&card->lock, flags);



	event->closure	     = client->bus_reset_closure;

	event->type          = FW_CDEV_EVENT_BUS_RESET;
@@ -220,22 +223,23 @@ fill_bus_reset_event(struct fw_cdev_event_bus_reset *event, 
	event->bm_node_id    = 0; /* FIXME: We don't track the BM. */

	event->irm_node_id   = card->irm_node->node_id;

	event->root_node_id  = card->root_node->node_id;



	spin_unlock_irqrestore(&card->lock, flags);

}



static void

for_each_client(struct fw_device *device,

		void (*callback)(struct client *client))

{

	struct fw_card *card = device->card;

	struct client *c;

	unsigned long flags;



	spin_lock_irqsave(&card->lock, flags);

	spin_lock_irqsave(&device->client_list_lock, flags);



	list_for_each_entry(c, &device->client_list, link)

		callback(c);



	spin_unlock_irqrestore(&card->lock, flags);

	spin_unlock_irqrestore(&device->client_list_lock, flags);

}



static void
@@ -274,11 +278,11 @@ static int ioctl_get_info(struct client *client, void *buffer) 
{

	struct fw_cdev_get_info *get_info = buffer;

	struct fw_cdev_event_bus_reset bus_reset;

	struct fw_card *card = client->device->card;

	unsigned long ret = 0;



	client->version = get_info->version;

	get_info->version = FW_CDEV_VERSION;

	get_info->card = client->device->card->index;



	down_read(&fw_device_rwsem);
@@ -300,18 +304,12 @@ static int ioctl_get_info(struct client *client, void *buffer) 
	client->bus_reset_closure = get_info->bus_reset_closure;

	if (get_info->bus_reset != 0) {

		void __user *uptr = u64_to_uptr(get_info->bus_reset);

		unsigned long flags;



		spin_lock_irqsave(&card->lock, flags);

		fill_bus_reset_event(&bus_reset, client);

		spin_unlock_irqrestore(&card->lock, flags);



		if (copy_to_user(uptr, &bus_reset, sizeof(bus_reset)))

			return -EFAULT;

	}



	get_info->card = card->index;



	return 0;

}
@@ -1009,9 +1007,9 @@ static int fw_device_op_release(struct inode *inode, struct file *file) 
	list_for_each_entry_safe(e, next_e, &client->event_list, link)

		kfree(e);



	spin_lock_irqsave(&client->device->card->lock, flags);

	spin_lock_irqsave(&client->device->client_list_lock, flags);

	list_del(&client->link);

	spin_unlock_irqrestore(&client->device->card->lock, flags);

	spin_unlock_irqrestore(&client->device->client_list_lock, flags);



	fw_device_put(client->device);

	kfree(client);

drivers/firewire/fw-device.c

+2 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/string.h>

#include <linux/rwsem.h>

#include <linux/semaphore.h>

#include <linux/spinlock.h>

#include <asm/system.h>

#include <linux/ctype.h>

#include "fw-transaction.h"
@@ -1004,6 +1005,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event) 
		device->node = fw_node_get(node);

		device->node_id = node->node_id;

		device->generation = card->generation;

		spin_lock_init(&device->client_list_lock);

		INIT_LIST_HEAD(&device->client_list);



		/*

drivers/firewire/fw-device.h

+3 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <linux/cdev.h>

#include <linux/idr.h>

#include <linux/rwsem.h>

#include <linux/spinlock.h>

#include <asm/atomic.h>



enum fw_device_state {
@@ -64,6 +65,8 @@ struct fw_device { 
	bool cmc;

	struct fw_card *card;

	struct device device;

	/* to prevent deadlocks, never take this lock with card->lock held */

	spinlock_t client_list_lock;

	struct list_head client_list;

	u32 *config_rom;

	size_t config_rom_length;