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authorRusty Russell <rusty@rustcorp.com.au>2007-05-08 00:26:42 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-08 11:15:03 -0700
commit9adef58b1d4fbb58d7daed931b6790c5a3b7543a (patch)
tree23e5ea2b0a140d244f2ed203b4954309d052e43d /include
parentaa5bd7e929325dbb48be43c3dccf7d1da433e38e (diff)
futex: get_futex_key, get_key_refs and drop_key_refs
lguest uses the convenient futex infrastructure for inter-domain I/O, so expose get_futex_key, get_key_refs (renamed get_futex_key_refs) and drop_key_refs (renamed drop_futex_key_refs). Also means we need to expose the union that these use. No code changes. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/futex.h29
1 files changed, 29 insertions, 0 deletions
diff --git a/include/linux/futex.h b/include/linux/futex.h
index 3f153b4e156..820125c628c 100644
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -100,6 +100,35 @@ long do_futex(u32 __user *uaddr, int op, u32 val, unsigned long timeout,
extern int
handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi);
+/*
+ * Futexes are matched on equal values of this key.
+ * The key type depends on whether it's a shared or private mapping.
+ * Don't rearrange members without looking at hash_futex().
+ *
+ * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
+ * We set bit 0 to indicate if it's an inode-based key.
+ */
+union futex_key {
+ struct {
+ unsigned long pgoff;
+ struct inode *inode;
+ int offset;
+ } shared;
+ struct {
+ unsigned long address;
+ struct mm_struct *mm;
+ int offset;
+ } private;
+ struct {
+ unsigned long word;
+ void *ptr;
+ int offset;
+ } both;
+};
+int get_futex_key(u32 __user *uaddr, union futex_key *key);
+void get_futex_key_refs(union futex_key *key);
+void drop_futex_key_refs(union futex_key *key);
+
#ifdef CONFIG_FUTEX
extern void exit_robust_list(struct task_struct *curr);
extern void exit_pi_state_list(struct task_struct *curr);