typos in "Linux Device Drivers Development"

I decided in retirement to fill the gaps in my education, so now I reading book "Linux Device Drivers Development" and noticed lots of annoying typos in code samples

page 65:
/* some where */
spinlock_t my_spinlock;
spin_lock_init(my_spinlock);
static irqreturn_t my_irq_handler(int irq, void *data)
{
 unsigned long status, flags;
 spin_lock_irqsave(&my_spinlock, flags);
 status = access_shared_resources();
 spin_unlock_irqrestore(&gpio->slock, flags); // wut? &my_spinlock
 return IRQ_HANDLED;
}

page 103-104:
struct my_data {
 int my_int_var;
 struct tasklet_struct the_tasklet;
 int dma_request;
};

static irqreturn_t my_irq_handler(int irq, void *dev_id)
{
  struct my_data *md = dev_id;
  /* Let's schedule our tasklet */
  tasklet_schedule(&md.dma_tasklet); // wut? &md->the_tasklet
  return IRQ_HANDLED;
}
 
page 127:
/* Move the cursor ten time, relative from the beginning of the file */
if (lseek(fd, 7, SEEK_SET) < 0)
return 1;

An so on. Seems that code samples looks like Frankenstein ripped from some random kernel places