error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types] .read = dev_read, Linux

I am getting the following error on my kernel code in linux for file operations.

Could you help me identify what's going wrong here?

Code:

struct GraphData{ unsigned long addr; long time;};static int position = 0;struct GraphData buffer[BUFFER_SIZE]; static int dev_open(struct inode *in,struct file *f);static ssize_t dev_read(struct file *f,struct GraphData *out,size_t count);static int dev_release(struct inode *inod,struct file *f);static struct file_operations fops ={  .read = dev_read,  .open = dev_open,  .release = dev_release};static int dev_open(struct inode *in, struct file *f){ printk(KERN_INFO " Device has been opened \n"); return 0;}static int dev_release(struct inode *in, struct file *f){  printk(KERN_INFO "Device successfully closed\n");  return 0;}static ssize_t dev_read(struct file *f,struct GraphData *out, size_t count){  int ret=0,i=0;  for(i=0;i<BUFFER_SIZE;i++)  {    count = copy_to_user(&out[i],&buffer[i],sizeof(buffer[i]));    if(count<0)    {        printk(KERN_ALERT "Copy!");        ret = -1;    }  }  return count;}

Kernel program has file operations, device could be passed a buffer and it stores data into the buffer

User Program

#define SIZE 500struct Buffer{  unsigned long addr;  long time;};int main(){ struct Buffer buf[SIZE]; int i=0; int errorFlag = 0; int fp = open("/proc/Probe",O_RDONLY); errorFlag = read(fp,buf,1);    printf("Page Fault Address           Time\n"); for(i=0;i<SIZE;i++) {    //printf("Read worked the Page fault address is 0x%lx caught at time  %ld\n",buf[i].address,buf[i].time);    printf("0x%lx           %ld\n",buf[i].addr,buf[i].time);}close(fp);return 0;}

The user program opens the file descriptor, reads from device and passes the buffer for kernel devce to copy into.

Error:error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types] .read = dev_read,/home/csvb/OS/assign4/hello2.c:36:12: note: (near initialization for ‘fops.read’)cc1: some warnings being treated as errors