diff options
author | Rusty Russell <rusty@rustcorp.com.au> | 2007-05-08 11:26:42 +0400 |
---|---|---|
committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-08 22:15:03 +0400 |
commit | 9adef58b1d4fbb58d7daed931b6790c5a3b7543a (patch) | |
tree | 23e5ea2b0a140d244f2ed203b4954309d052e43d /kernel/futex.c | |
parent | aa5bd7e929325dbb48be43c3dccf7d1da433e38e (diff) | |
download | linux-9adef58b1d4fbb58d7daed931b6790c5a3b7543a.tar.xz |
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 'kernel/futex.c')
-rw-r--r-- | kernel/futex.c | 50 |
1 files changed, 14 insertions, 36 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 5a270b5e3f95..7ae2f50641ed 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -48,6 +48,7 @@ #include <linux/pagemap.h> #include <linux/syscalls.h> #include <linux/signal.h> +#include <linux/module.h> #include <asm/futex.h> #include "rtmutex_common.h" @@ -55,32 +56,6 @@ #define FUTEX_HASHBITS (CONFIG_BASE_SMALL ? 4 : 8) /* - * 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; -}; - -/* * Priority Inheritance state: */ struct futex_pi_state { @@ -175,7 +150,7 @@ static inline int match_futex(union futex_key *key1, union futex_key *key2) * * Should be called with ¤t->mm->mmap_sem but NOT any spinlocks. */ -static int get_futex_key(u32 __user *uaddr, union futex_key *key) +int get_futex_key(u32 __user *uaddr, union futex_key *key) { unsigned long address = (unsigned long)uaddr; struct mm_struct *mm = current->mm; @@ -246,6 +221,7 @@ static int get_futex_key(u32 __user *uaddr, union futex_key *key) } return err; } +EXPORT_SYMBOL_GPL(get_futex_key); /* * Take a reference to the resource addressed by a key. @@ -254,7 +230,7 @@ static int get_futex_key(u32 __user *uaddr, union futex_key *key) * NOTE: mmap_sem MUST be held between get_futex_key() and calling this * function, if it is called at all. mmap_sem keeps key->shared.inode valid. */ -static inline void get_key_refs(union futex_key *key) +inline void get_futex_key_refs(union futex_key *key) { if (key->both.ptr != 0) { if (key->both.offset & 1) @@ -263,12 +239,13 @@ static inline void get_key_refs(union futex_key *key) atomic_inc(&key->private.mm->mm_count); } } +EXPORT_SYMBOL_GPL(get_futex_key_refs); /* * Drop a reference to the resource addressed by a key. * The hash bucket spinlock must not be held. */ -static void drop_key_refs(union futex_key *key) +void drop_futex_key_refs(union futex_key *key) { if (key->both.ptr != 0) { if (key->both.offset & 1) @@ -277,6 +254,7 @@ static void drop_key_refs(union futex_key *key) mmdrop(key->private.mm); } } +EXPORT_SYMBOL_GPL(drop_futex_key_refs); static inline int get_futex_value_locked(u32 *dest, u32 __user *from) { @@ -873,7 +851,7 @@ static int futex_requeue(u32 __user *uaddr1, u32 __user *uaddr2, this->lock_ptr = &hb2->lock; } this->key = key2; - get_key_refs(&key2); + get_futex_key_refs(&key2); drop_count++; if (ret - nr_wake >= nr_requeue) @@ -886,9 +864,9 @@ out_unlock: if (hb1 != hb2) spin_unlock(&hb2->lock); - /* drop_key_refs() must be called outside the spinlocks. */ + /* drop_futex_key_refs() must be called outside the spinlocks. */ while (--drop_count >= 0) - drop_key_refs(&key1); + drop_futex_key_refs(&key1); out: up_read(¤t->mm->mmap_sem); @@ -906,7 +884,7 @@ queue_lock(struct futex_q *q, int fd, struct file *filp) init_waitqueue_head(&q->waiters); - get_key_refs(&q->key); + get_futex_key_refs(&q->key); hb = hash_futex(&q->key); q->lock_ptr = &hb->lock; @@ -925,7 +903,7 @@ static inline void queue_unlock(struct futex_q *q, struct futex_hash_bucket *hb) { spin_unlock(&hb->lock); - drop_key_refs(&q->key); + drop_futex_key_refs(&q->key); } /* @@ -980,7 +958,7 @@ static int unqueue_me(struct futex_q *q) ret = 1; } - drop_key_refs(&q->key); + drop_futex_key_refs(&q->key); return ret; } @@ -999,7 +977,7 @@ static void unqueue_me_pi(struct futex_q *q, struct futex_hash_bucket *hb) spin_unlock(&hb->lock); - drop_key_refs(&q->key); + drop_futex_key_refs(&q->key); } static int futex_wait(u32 __user *uaddr, u32 val, unsigned long time) |