Commit c7b2a99c authored by Stefan Richter's avatar Stefan Richter
Browse files

firewire: nosy: convert to unlocked ioctl 



The required serialization of NOSY_IOC_START and NOSY_IOC_STOP is
already provided by the client_list_lock.

NOSY_IOC_FILTER does not really require serialization since accesses
to tcode_mask are atomic on any sane CPU architecture.  Nevertheless,
make it explicit that we want this to be atomic by means of
client_list_lock (which also surrounds the other tcode_mask access in
the IRQ handler).  While we are at it, change the type of tcode_mask to
u32 for consistency with the user API.

NOSY_IOC_GET_STATS does not require serialization against itself.  But
there is a bug here regarding concurrent updates of the two counters
by the IRQ handler.  Fix it by taking the client_list_lock in this ioctl
too.

Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent b5e47729

drivers/firewire/nosy.c

+17 −12
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ struct pcilynx { 


struct client {

	struct pcilynx *lynx;

	unsigned long tcode_mask;

	u32 tcode_mask;

	struct packet_buffer buffer;

	struct list_head link;

};
@@ -351,17 +351,20 @@ nosy_read(struct file *file, char *buffer, size_t count, loff_t *offset) 
	return packet_buffer_get(&client->buffer, buffer, count);

}



static int

nosy_ioctl(struct inode *inode, struct file *file,

	   unsigned int cmd, unsigned long arg)

static long

nosy_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	struct client *client = file->private_data;

	spinlock_t *client_list_lock = &client->lynx->client_list_lock;

	struct nosy_stats stats;



	switch (cmd) {

	case NOSY_IOC_GET_STATS:

		spin_lock_irq(client_list_lock);

		stats.total_packet_count = client->buffer.total_packet_count;

		stats.lost_packet_count  = client->buffer.lost_packet_count;

		spin_unlock_irq(client_list_lock);



		if (copy_to_user((void *) arg, &stats, sizeof stats))

			return -EFAULT;

		else
@@ -376,7 +379,9 @@ nosy_ioctl(struct inode *inode, struct file *file, 
		return 0;



	case NOSY_IOC_FILTER:

		spin_lock_irq(client_list_lock);

		client->tcode_mask = arg;

		spin_unlock_irq(client_list_lock);

		return 0;



	default:
@@ -388,7 +393,7 @@ nosy_ioctl(struct inode *inode, struct file *file, 
static const struct file_operations nosy_ops = {

	.owner =		THIS_MODULE,

	.read =			nosy_read,

	.ioctl =	nosy_ioctl,

	.unlocked_ioctl =	nosy_ioctl,

	.poll =			nosy_poll,

	.open =			nosy_open,

	.release =		nosy_release,
@@ -409,7 +414,7 @@ packet_handler(struct pcilynx *lynx) 
{

	unsigned long flags;

	struct client *client;

	unsigned long tcode_mask;

	u32 tcode_mask;

	size_t length;

	struct link_packet *packet;

	struct timeval tv;

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