diff options
| -rw-r--r-- | include/linux/futex.h | 29 | ||||
| -rw-r--r-- | kernel/futex.c | 50 |
2 files changed, 43 insertions, 36 deletions
diff --git a/include/linux/futex.h b/include/linux/futex.h index 3f153b4..820125c 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); diff --git a/kernel/futex.c b/kernel/futex.c index 5a270b5..7ae2f50 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) |
