get_futex_key (9) Linux Manual Page
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.com.au>
- Author.