nbd: Remove variable 'pid'

This patch uses nbd->task_recv to determine the value of the previously
used variable 'pid' for sysfs.
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/block/nbd.c

@@ -55,7 +55,6 @@ struct nbd_device {
 	struct gendisk *disk;
 	int blksize;
 	loff_t bytesize;
-	pid_t pid; /* pid of nbd-client, if attached */
 	int xmit_timeout;
 	int disconnect; /* a disconnect has been requested by user */
 
@@ -379,9 +378,9 @@ static ssize_t pid_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
 	struct gendisk *disk = dev_to_disk(dev);
+	struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
 
-	return sprintf(buf, "%ld\n",
-		(long) ((struct nbd_device *)disk->private_data)->pid);
+	return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
 }
 
 static struct device_attribute pid_attr = {
@@ -397,16 +396,16 @@ static int nbd_do_it(struct nbd_device *nbd)
 	BUG_ON(nbd->magic != NBD_MAGIC);
 
 	sk_set_memalloc(nbd->sock->sk);
-	nbd->pid = task_pid_nr(current);
+
+	nbd->task_recv = current;
+
 	ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
 	if (ret) {
 		dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
-		nbd->pid = 0;
+		nbd->task_recv = NULL;
 		return ret;
 	}
 
-	nbd->task_recv = current;
-
 	while (1) {
 		req = nbd_read_stat(nbd);
 		if (IS_ERR(req)) {
@@ -417,6 +416,8 @@ static int nbd_do_it(struct nbd_device *nbd)
 		nbd_end_request(nbd, req);
 	}
 
+	device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
+
 	nbd->task_recv = NULL;
 
 	if (signal_pending(current)) {
@@ -431,8 +432,6 @@ static int nbd_do_it(struct nbd_device *nbd)
 		ret = -ETIMEDOUT;
 	}
 
-	device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
-	nbd->pid = 0;
 	return ret;
 }
 
@@ -708,7 +707,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
 		struct socket *sock;
 		int error;
 
-		if (nbd->pid)
+		if (nbd->task_recv)
 			return -EBUSY;
 		if (!nbd->sock)
 			return -EINVAL;