GET_FUTEX_KEY(9)                       Futex API reference                       GET_FUTEX_KEY(9)



NAME
       get_futex_key - Get parameters which are the keys for a futex

SYNOPSIS
       int get_futex_key(u32 __user * uaddr, int fshared, union futex_key * key, int rw);

ARGUMENTS
       uaddr
           virtual address of the futex

       fshared
           0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED

       key
           address where result is stored.

       rw
           mapping needs to be read/write (values: VERIFY_READ, VERIFY_WRITE)

RETURN
       a negative error code or 0

       The key words are stored in *key on success.

       For shared mappings, it's (page->index, file_inode(vma->vm_file), offset_within_page). For
       private mappings, it's (uaddr, current->mm). We can usually work out the index without
       swapping in the page.

       lock_page might sleep, the caller should not hold a spinlock.

AUTHOR
       Rusty Russell <rusty AT rustcorp.au>
           Author.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                          GET_FUTEX_KEY(9)