Scull Driver - Read

sahil aggarwal sahil.agg15 at gmail.com
Sun Mar 15 00:47:30 EDT 2015


hi all,

Going through scull driver code, i see read function reads only till
end of 1 quantum, so do kernel call read multiple times if count from
q_pos exceeds quantum size limit.?


Ref: ldd3.

if(count > quantum - q_pos)
count = quantum - q_pos;
if(copy_to_user(buf, dptr->data[s_pos] + q_pos,count)){
retval = -EFAULT;
goto out;
}
*f_pos += count;
retval = count;

Thanks
Regards



More information about the Kernelnewbies mailing list