* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
* Copyright (C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
*
+ * PRIVATE futexes by Eric Dumazet
+ * Copyright (C) 2007 Eric Dumazet <dada1@cosmosbay.com>
+ *
* Thanks to Ben LaHaise for yelling "hashed waitqueues" loudly
* enough at me, Linus for the original (flawed) idea, Matthew
* Kirkwood for proof-of-concept implementation.
#include <linux/pagemap.h>
#include <linux/syscalls.h>
#include <linux/signal.h>
+#include <linux/module.h>
+#include <linux/magic.h>
#include <asm/futex.h>
#include "rtmutex_common.h"
#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:
*/
* we can wake only the relevant ones (hashed queues may be shared).
*
* A futex_q has a woken state, just like tasks have TASK_RUNNING.
- * It is considered woken when list_empty(&q->list) || q->lock_ptr == 0.
+ * It is considered woken when plist_node_empty(&q->list) || q->lock_ptr == 0.
* The order of wakup is always to make the first condition true, then
* wake up q->waiters, then make the second condition true.
*/
struct futex_q {
- struct list_head list;
+ struct plist_node list;
wait_queue_head_t waiters;
/* Which hash list lock to use: */
* Split the global futex_lock into every hash list lock.
*/
struct futex_hash_bucket {
- spinlock_t lock;
- struct list_head chain;
+ spinlock_t lock;
+ struct plist_head chain;
};
static struct futex_hash_bucket futex_queues[1<<FUTEX_HASHBITS];
/* Futex-fs vfsmount entry: */
static struct vfsmount *futex_mnt;
+/*
+ * Take mm->mmap_sem, when futex is shared
+ */
+static inline void futex_lock_mm(struct rw_semaphore *fshared)
+{
+ if (fshared)
+ down_read(fshared);
+}
+
+/*
+ * Release mm->mmap_sem, when the futex is shared
+ */
+static inline void futex_unlock_mm(struct rw_semaphore *fshared)
+{
+ if (fshared)
+ up_read(fshared);
+}
+
/*
* We hash on the keys returned from get_futex_key (see below).
*/
&& key1->both.offset == key2->both.offset);
}
-/*
- * Get parameters which are the keys for a futex.
+/**
+ * get_futex_key - Get parameters which are the keys for a futex.
+ * @uaddr: virtual address of the futex
+ * @shared: NULL for a PROCESS_PRIVATE futex,
+ * ¤t->mm->mmap_sem for a PROCESS_SHARED futex
+ * @key: address where result is stored.
+ *
+ * Returns a negative error code or 0
+ * The key words are stored in *key on success.
*
- * For shared mappings, it's (page->index, vma->vm_file->f_dentry->d_inode,
+ * For shared mappings, it's (page->index, vma->vm_file->f_path.dentry->d_inode,
* offset_within_page). For private mappings, it's (uaddr, current->mm).
* We can usually work out the index without swapping in the page.
*
- * Returns: 0, or negative error code.
- * The key words are stored in *key on success.
- *
- * Should be called with ¤t->mm->mmap_sem but NOT any spinlocks.
+ * fshared is NULL for PROCESS_PRIVATE futexes
+ * For other futexes, it points to ¤t->mm->mmap_sem and
+ * caller must have taken the reader lock. but NOT any spinlocks.
*/
-static int get_futex_key(u32 __user *uaddr, union futex_key *key)
+int get_futex_key(u32 __user *uaddr, struct rw_semaphore *fshared,
+ union futex_key *key)
{
unsigned long address = (unsigned long)uaddr;
struct mm_struct *mm = current->mm;
* The futex address must be "naturally" aligned.
*/
key->both.offset = address % PAGE_SIZE;
- if (unlikely((key->both.offset % sizeof(u32)) != 0))
+ if (unlikely((address % sizeof(u32)) != 0))
return -EINVAL;
address -= key->both.offset;
+ /*
+ * PROCESS_PRIVATE futexes are fast.
+ * As the mm cannot disappear under us and the 'key' only needs
+ * virtual address, we dont even have to find the underlying vma.
+ * Note : We do have to check 'uaddr' is a valid user address,
+ * but access_ok() should be faster than find_vma()
+ */
+ if (!fshared) {
+ if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))))
+ return -EFAULT;
+ key->private.mm = mm;
+ key->private.address = address;
+ return 0;
+ }
/*
* The futex is hashed differently depending on whether
* it's in a shared or private mapping. So check vma first.
* mappings of _writable_ handles.
*/
if (likely(!(vma->vm_flags & VM_MAYSHARE))) {
+ key->both.offset |= FUT_OFF_MMSHARED; /* reference taken on mm */
key->private.mm = mm;
key->private.address = address;
return 0;
/*
* Linear file mappings are also simple.
*/
- key->shared.inode = vma->vm_file->f_dentry->d_inode;
- key->both.offset++; /* Bit 0 of offset indicates inode-based key. */
+ key->shared.inode = vma->vm_file->f_path.dentry->d_inode;
+ key->both.offset |= FUT_OFF_INODE; /* inode-based key. */
if (likely(!(vma->vm_flags & VM_NONLINEAR))) {
key->shared.pgoff = (((address - vma->vm_start) >> PAGE_SHIFT)
+ vma->vm_pgoff);
}
return err;
}
+EXPORT_SYMBOL_GPL(get_futex_key);
/*
* Take a reference to the resource addressed by a key.
* Can be called while holding spinlocks.
*
- * 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)
+ if (key->both.ptr == 0)
+ return;
+ switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
+ case FUT_OFF_INODE:
atomic_inc(&key->shared.inode->i_count);
- else
+ break;
+ case FUT_OFF_MMSHARED:
atomic_inc(&key->private.mm->mm_count);
+ break;
}
}
+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)
+ if (!key->both.ptr)
+ return;
+ switch (key->both.offset & (FUT_OFF_INODE|FUT_OFF_MMSHARED)) {
+ case FUT_OFF_INODE:
iput(key->shared.inode);
- else
+ break;
+ case FUT_OFF_MMSHARED:
mmdrop(key->private.mm);
+ break;
}
}
+EXPORT_SYMBOL_GPL(drop_futex_key_refs);
+
+static u32 cmpxchg_futex_value_locked(u32 __user *uaddr, u32 uval, u32 newval)
+{
+ u32 curval;
+
+ pagefault_disable();
+ curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
+ pagefault_enable();
+
+ return curval;
+}
-static inline int get_futex_value_locked(u32 *dest, u32 __user *from)
+static int get_futex_value_locked(u32 *dest, u32 __user *from)
{
int ret;
- inc_preempt_count();
+ pagefault_disable();
ret = __copy_from_user_inatomic(dest, from, sizeof(u32));
- dec_preempt_count();
+ pagefault_enable();
return ret ? -EFAULT : 0;
}
/*
- * Fault handling. Called with current->mm->mmap_sem held.
+ * Fault handling.
+ * if fshared is non NULL, current->mm->mmap_sem is already held
*/
-static int futex_handle_fault(unsigned long address, int attempt)
+static int futex_handle_fault(unsigned long address,
+ struct rw_semaphore *fshared, int attempt)
{
struct vm_area_struct * vma;
struct mm_struct *mm = current->mm;
+ int ret = -EFAULT;
- if (attempt > 2 || !(vma = find_vma(mm, address)) ||
- vma->vm_start > address || !(vma->vm_flags & VM_WRITE))
- return -EFAULT;
+ if (attempt > 2)
+ return ret;
- switch (handle_mm_fault(mm, vma, address, 1)) {
- case VM_FAULT_MINOR:
- current->min_flt++;
- break;
- case VM_FAULT_MAJOR:
- current->maj_flt++;
- break;
- default:
- return -EFAULT;
+ if (!fshared)
+ down_read(&mm->mmap_sem);
+ vma = find_vma(mm, address);
+ if (vma && address >= vma->vm_start &&
+ (vma->vm_flags & VM_WRITE)) {
+ int fault;
+ fault = handle_mm_fault(mm, vma, address, 1);
+ if (unlikely((fault & VM_FAULT_ERROR))) {
+#if 0
+ /* XXX: let's do this when we verify it is OK */
+ if (ret & VM_FAULT_OOM)
+ ret = -ENOMEM;
+#endif
+ } else {
+ ret = 0;
+ if (fault & VM_FAULT_MAJOR)
+ current->maj_flt++;
+ else
+ current->min_flt++;
+ }
}
- return 0;
+ if (!fshared)
+ up_read(&mm->mmap_sem);
+ return ret;
}
/*
if (likely(current->pi_state_cache))
return 0;
- pi_state = kmalloc(sizeof(*pi_state), GFP_KERNEL);
+ pi_state = kzalloc(sizeof(*pi_state), GFP_KERNEL);
if (!pi_state)
return -ENOMEM;
- memset(pi_state, 0, sizeof(*pi_state));
INIT_LIST_HEAD(&pi_state->list);
/* pi_mutex gets initialized later */
pi_state->owner = NULL;
rcu_read_lock();
p = find_task_by_pid(pid);
- if (!p)
- goto out_unlock;
- if ((current->euid != p->euid) && (current->euid != p->uid)) {
- p = NULL;
- goto out_unlock;
- }
- if (p->exit_state != 0) {
- p = NULL;
- goto out_unlock;
- }
- get_task_struct(p);
-out_unlock:
+
+ if (!p || ((current->euid != p->euid) && (current->euid != p->uid)))
+ p = ERR_PTR(-ESRCH);
+ else
+ get_task_struct(p);
+
rcu_read_unlock();
return p;
}
static int
-lookup_pi_state(u32 uval, struct futex_hash_bucket *hb, struct futex_q *me)
+lookup_pi_state(u32 uval, struct futex_hash_bucket *hb,
+ union futex_key *key, struct futex_pi_state **ps)
{
struct futex_pi_state *pi_state = NULL;
struct futex_q *this, *next;
- struct list_head *head;
+ struct plist_head *head;
struct task_struct *p;
- pid_t pid;
+ pid_t pid = uval & FUTEX_TID_MASK;
head = &hb->chain;
- list_for_each_entry_safe(this, next, head, list) {
- if (match_futex(&this->key, &me->key)) {
+ plist_for_each_entry_safe(this, next, head, list) {
+ if (match_futex(&this->key, key)) {
/*
* Another waiter already exists - bump up
* the refcount and return its pi_state:
return -EINVAL;
WARN_ON(!atomic_read(&pi_state->refcount));
+ WARN_ON(pid && pi_state->owner &&
+ pi_state->owner->pid != pid);
atomic_inc(&pi_state->refcount);
- me->pi_state = pi_state;
+ *ps = pi_state;
return 0;
}
/*
* We are the first waiter - try to look up the real owner and attach
- * the new pi_state to it, but bail out when the owner died bit is set
- * and TID = 0:
+ * the new pi_state to it, but bail out when TID = 0
*/
- pid = uval & FUTEX_TID_MASK;
- if (!pid && (uval & FUTEX_OWNER_DIED))
+ if (!pid)
return -ESRCH;
p = futex_find_get_task(pid);
- if (!p)
- return -ESRCH;
+ if (IS_ERR(p))
+ return PTR_ERR(p);
+
+ /*
+ * We need to look at the task state flags to figure out,
+ * whether the task is exiting. To protect against the do_exit
+ * change of the task flags, we do this protected by
+ * p->pi_lock:
+ */
+ spin_lock_irq(&p->pi_lock);
+ if (unlikely(p->flags & PF_EXITING)) {
+ /*
+ * The task is on the way out. When PF_EXITPIDONE is
+ * set, we know that the task has finished the
+ * cleanup:
+ */
+ int ret = (p->flags & PF_EXITPIDONE) ? -ESRCH : -EAGAIN;
+
+ spin_unlock_irq(&p->pi_lock);
+ put_task_struct(p);
+ return ret;
+ }
pi_state = alloc_pi_state();
rt_mutex_init_proxy_locked(&pi_state->pi_mutex, p);
/* Store the key for possible exit cleanups: */
- pi_state->key = me->key;
+ pi_state->key = *key;
- spin_lock_irq(&p->pi_lock);
WARN_ON(!list_empty(&pi_state->list));
list_add(&pi_state->list, &p->pi_state_list);
pi_state->owner = p;
put_task_struct(p);
- me->pi_state = pi_state;
+ *ps = pi_state;
return 0;
}
*/
static void wake_futex(struct futex_q *q)
{
- list_del_init(&q->list);
+ plist_del(&q->list, &q->list.plist);
if (q->filp)
send_sigio(&q->filp->f_owner, q->fd, POLL_IN);
/*
* The lock in wake_up_all() is a crucial memory barrier after the
- * list_del_init() and also before assigning to q->lock_ptr.
+ * plist_del() and also before assigning to q->lock_ptr.
*/
wake_up_all(&q->waiters);
/*
* at the end of wake_up_all() does not prevent this store from
* moving.
*/
- wmb();
+ smp_wmb();
q->lock_ptr = NULL;
}
if (!pi_state)
return -EINVAL;
+ spin_lock(&pi_state->pi_mutex.wait_lock);
new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
/*
* preserve the owner died bit.)
*/
if (!(uval & FUTEX_OWNER_DIED)) {
+ int ret = 0;
+
newval = FUTEX_WAITERS | new_owner->pid;
- inc_preempt_count();
- curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
- dec_preempt_count();
+ curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
+
if (curval == -EFAULT)
- return -EFAULT;
+ ret = -EFAULT;
if (curval != uval)
- return -EINVAL;
+ ret = -EINVAL;
+ if (ret) {
+ spin_unlock(&pi_state->pi_mutex.wait_lock);
+ return ret;
+ }
}
spin_lock_irq(&pi_state->owner->pi_lock);
pi_state->owner = new_owner;
spin_unlock_irq(&new_owner->pi_lock);
+ spin_unlock(&pi_state->pi_mutex.wait_lock);
rt_mutex_unlock(&pi_state->pi_mutex);
return 0;
* There is no waiter, so we unlock the futex. The owner died
* bit has not to be preserved here. We are the owner:
*/
- inc_preempt_count();
- oldval = futex_atomic_cmpxchg_inatomic(uaddr, uval, 0);
- dec_preempt_count();
+ oldval = cmpxchg_futex_value_locked(uaddr, uval, 0);
if (oldval == -EFAULT)
return oldval;
* Wake up all waiters hashed on the physical page that is mapped
* to this virtual address:
*/
-static int futex_wake(u32 __user *uaddr, int nr_wake)
+static int futex_wake(u32 __user *uaddr, struct rw_semaphore *fshared,
+ int nr_wake)
{
struct futex_hash_bucket *hb;
struct futex_q *this, *next;
- struct list_head *head;
+ struct plist_head *head;
union futex_key key;
int ret;
- down_read(¤t->mm->mmap_sem);
+ futex_lock_mm(fshared);
- ret = get_futex_key(uaddr, &key);
+ ret = get_futex_key(uaddr, fshared, &key);
if (unlikely(ret != 0))
goto out;
spin_lock(&hb->lock);
head = &hb->chain;
- list_for_each_entry_safe(this, next, head, list) {
+ plist_for_each_entry_safe(this, next, head, list) {
if (match_futex (&this->key, &key)) {
if (this->pi_state) {
ret = -EINVAL;
spin_unlock(&hb->lock);
out:
- up_read(¤t->mm->mmap_sem);
+ futex_unlock_mm(fshared);
return ret;
}
* to this virtual address:
*/
static int
-futex_wake_op(u32 __user *uaddr1, u32 __user *uaddr2,
+futex_wake_op(u32 __user *uaddr1, struct rw_semaphore *fshared,
+ u32 __user *uaddr2,
int nr_wake, int nr_wake2, int op)
{
union futex_key key1, key2;
struct futex_hash_bucket *hb1, *hb2;
- struct list_head *head;
+ struct plist_head *head;
struct futex_q *this, *next;
int ret, op_ret, attempt = 0;
retryfull:
- down_read(¤t->mm->mmap_sem);
+ futex_lock_mm(fshared);
- ret = get_futex_key(uaddr1, &key1);
+ ret = get_futex_key(uaddr1, fshared, &key1);
if (unlikely(ret != 0))
goto out;
- ret = get_futex_key(uaddr2, &key2);
+ ret = get_futex_key(uaddr2, fshared, &key2);
if (unlikely(ret != 0))
goto out;
* still holding the mmap_sem.
*/
if (attempt++) {
- if (futex_handle_fault((unsigned long)uaddr2,
- attempt)) {
- ret = -EFAULT;
+ ret = futex_handle_fault((unsigned long)uaddr2,
+ fshared, attempt);
+ if (ret)
goto out;
- }
goto retry;
}
* If we would have faulted, release mmap_sem,
* fault it in and start all over again.
*/
- up_read(¤t->mm->mmap_sem);
+ futex_unlock_mm(fshared);
ret = get_user(dummy, uaddr2);
if (ret)
head = &hb1->chain;
- list_for_each_entry_safe(this, next, head, list) {
+ plist_for_each_entry_safe(this, next, head, list) {
if (match_futex (&this->key, &key1)) {
wake_futex(this);
if (++ret >= nr_wake)
head = &hb2->chain;
op_ret = 0;
- list_for_each_entry_safe(this, next, head, list) {
+ plist_for_each_entry_safe(this, next, head, list) {
if (match_futex (&this->key, &key2)) {
wake_futex(this);
if (++op_ret >= nr_wake2)
if (hb1 != hb2)
spin_unlock(&hb2->lock);
out:
- up_read(¤t->mm->mmap_sem);
+ futex_unlock_mm(fshared);
+
return ret;
}
* Requeue all waiters hashed on one physical page to another
* physical page.
*/
-static int futex_requeue(u32 __user *uaddr1, u32 __user *uaddr2,
+static int futex_requeue(u32 __user *uaddr1, struct rw_semaphore *fshared,
+ u32 __user *uaddr2,
int nr_wake, int nr_requeue, u32 *cmpval)
{
union futex_key key1, key2;
struct futex_hash_bucket *hb1, *hb2;
- struct list_head *head1;
+ struct plist_head *head1;
struct futex_q *this, *next;
int ret, drop_count = 0;
retry:
- down_read(¤t->mm->mmap_sem);
+ futex_lock_mm(fshared);
- ret = get_futex_key(uaddr1, &key1);
+ ret = get_futex_key(uaddr1, fshared, &key1);
if (unlikely(ret != 0))
goto out;
- ret = get_futex_key(uaddr2, &key2);
+ ret = get_futex_key(uaddr2, fshared, &key2);
if (unlikely(ret != 0))
goto out;
* If we would have faulted, release mmap_sem, fault
* it in and start all over again.
*/
- up_read(¤t->mm->mmap_sem);
+ futex_unlock_mm(fshared);
ret = get_user(curval, uaddr1);
}
head1 = &hb1->chain;
- list_for_each_entry_safe(this, next, head1, list) {
+ plist_for_each_entry_safe(this, next, head1, list) {
if (!match_futex (&this->key, &key1))
continue;
if (++ret <= nr_wake) {
* requeue.
*/
if (likely(head1 != &hb2->chain)) {
- list_move_tail(&this->list, &hb2->chain);
+ plist_del(&this->list, &hb1->chain);
+ plist_add(&this->list, &hb2->chain);
this->lock_ptr = &hb2->lock;
+#ifdef CONFIG_DEBUG_PI_LIST
+ this->list.plist.lock = &hb2->lock;
+#endif
}
this->key = key2;
- get_key_refs(&key2);
+ get_futex_key_refs(&key2);
drop_count++;
if (ret - nr_wake >= nr_requeue)
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);
+ futex_unlock_mm(fshared);
return ret;
}
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;
static inline void __queue_me(struct futex_q *q, struct futex_hash_bucket *hb)
{
- list_add_tail(&q->list, &hb->chain);
+ int prio;
+
+ /*
+ * The priority used to register this element is
+ * - either the real thread-priority for the real-time threads
+ * (i.e. threads with a priority lower than MAX_RT_PRIO)
+ * - or MAX_RT_PRIO for non-RT threads.
+ * Thus, all RT-threads are woken first in priority order, and
+ * the others are woken last, in FIFO order.
+ */
+ prio = min(current->normal_prio, MAX_RT_PRIO);
+
+ plist_node_init(&q->list, prio);
+#ifdef CONFIG_DEBUG_PI_LIST
+ q->list.plist.lock = &hb->lock;
+#endif
+ plist_add(&q->list, &hb->chain);
q->task = current;
spin_unlock(&hb->lock);
}
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);
}
/*
retry:
lock_ptr = q->lock_ptr;
barrier();
- if (lock_ptr != 0) {
+ if (lock_ptr != NULL) {
spin_lock(lock_ptr);
/*
* q->lock_ptr can change between reading it and
spin_unlock(lock_ptr);
goto retry;
}
- WARN_ON(list_empty(&q->list));
- list_del(&q->list);
+ WARN_ON(plist_node_empty(&q->list));
+ plist_del(&q->list, &q->list.plist);
BUG_ON(q->pi_state);
ret = 1;
}
- drop_key_refs(&q->key);
+ drop_futex_key_refs(&q->key);
return ret;
}
/*
* PI futexes can not be requeued and must remove themself from the
- * hash bucket. The hash bucket lock is held on entry and dropped here.
+ * hash bucket. The hash bucket lock (i.e. lock_ptr) is held on entry
+ * and dropped here.
*/
-static void unqueue_me_pi(struct futex_q *q, struct futex_hash_bucket *hb)
+static void unqueue_me_pi(struct futex_q *q)
{
- WARN_ON(list_empty(&q->list));
- list_del(&q->list);
+ WARN_ON(plist_node_empty(&q->list));
+ plist_del(&q->list, &q->list.plist);
BUG_ON(!q->pi_state);
free_pi_state(q->pi_state);
q->pi_state = NULL;
- spin_unlock(&hb->lock);
+ spin_unlock(q->lock_ptr);
- drop_key_refs(&q->key);
+ drop_futex_key_refs(&q->key);
}
-static int futex_wait(u32 __user *uaddr, u32 val, unsigned long time)
+/*
+ * Fixup the pi_state owner with current.
+ *
+ * Must be called with hash bucket lock held and mm->sem held for non
+ * private futexes.
+ */
+static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
+ struct task_struct *curr)
+{
+ u32 newtid = curr->pid | FUTEX_WAITERS;
+ struct futex_pi_state *pi_state = q->pi_state;
+ u32 uval, curval, newval;
+ int ret;
+
+ /* Owner died? */
+ if (pi_state->owner != NULL) {
+ spin_lock_irq(&pi_state->owner->pi_lock);
+ WARN_ON(list_empty(&pi_state->list));
+ list_del_init(&pi_state->list);
+ spin_unlock_irq(&pi_state->owner->pi_lock);
+ } else
+ newtid |= FUTEX_OWNER_DIED;
+
+ pi_state->owner = curr;
+
+ spin_lock_irq(&curr->pi_lock);
+ WARN_ON(!list_empty(&pi_state->list));
+ list_add(&pi_state->list, &curr->pi_state_list);
+ spin_unlock_irq(&curr->pi_lock);
+
+ /*
+ * We own it, so we have to replace the pending owner
+ * TID. This must be atomic as we have preserve the
+ * owner died bit here.
+ */
+ ret = get_futex_value_locked(&uval, uaddr);
+
+ while (!ret) {
+ newval = (uval & FUTEX_OWNER_DIED) | newtid;
+
+ curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
+
+ if (curval == -EFAULT)
+ ret = -EFAULT;
+ if (curval == uval)
+ break;
+ uval = curval;
+ }
+ return ret;
+}
+
+/*
+ * In case we must use restart_block to restart a futex_wait,
+ * we encode in the 'arg3' shared capability
+ */
+#define ARG3_SHARED 1
+
+static long futex_wait_restart(struct restart_block *restart);
+
+static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
+ u32 val, ktime_t *abs_time)
{
struct task_struct *curr = current;
DECLARE_WAITQUEUE(wait, curr);
struct futex_q q;
u32 uval;
int ret;
+ struct hrtimer_sleeper t;
+ int rem = 0;
q.pi_state = NULL;
retry:
- down_read(&curr->mm->mmap_sem);
+ futex_lock_mm(fshared);
- ret = get_futex_key(uaddr, &q.key);
+ ret = get_futex_key(uaddr, fshared, &q.key);
if (unlikely(ret != 0))
goto out_release_sem;
* a wakeup when *uaddr != val on entry to the syscall. This is
* rare, but normal.
*
- * We hold the mmap semaphore, so the mapping cannot have changed
- * since we looked it up in get_futex_key.
+ * for shared futexes, we hold the mmap semaphore, so the mapping
+ * cannot have changed since we looked it up in get_futex_key.
*/
ret = get_futex_value_locked(&uval, uaddr);
* If we would have faulted, release mmap_sem, fault it in and
* start all over again.
*/
- up_read(&curr->mm->mmap_sem);
+ futex_unlock_mm(fshared);
ret = get_user(uval, uaddr);
* Now the futex is queued and we have checked the data, we
* don't want to hold mmap_sem while we sleep.
*/
- up_read(&curr->mm->mmap_sem);
+ futex_unlock_mm(fshared);
/*
* There might have been scheduling since the queue_me(), as we
__set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&q.waiters, &wait);
/*
- * !list_empty() is safe here without any lock.
+ * !plist_node_empty() is safe here without any lock.
* q.lock_ptr != 0 is not safe, because of ordering against wakeup.
*/
- if (likely(!list_empty(&q.list)))
- time = schedule_timeout(time);
+ if (likely(!plist_node_empty(&q.list))) {
+ if (!abs_time)
+ schedule();
+ else {
+ hrtimer_init(&t.timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ hrtimer_init_sleeper(&t, current);
+ t.timer.expires = *abs_time;
+
+ hrtimer_start(&t.timer, t.timer.expires, HRTIMER_MODE_ABS);
+
+ /*
+ * the timer could have already expired, in which
+ * case current would be flagged for rescheduling.
+ * Don't bother calling schedule.
+ */
+ if (likely(t.task))
+ schedule();
+
+ hrtimer_cancel(&t.timer);
+
+ /* Flag if a timeout occured */
+ rem = (t.task == NULL);
+ }
+ }
__set_current_state(TASK_RUNNING);
/*
/* If we were woken (and unqueued), we succeeded, whatever. */
if (!unqueue_me(&q))
return 0;
- if (time == 0)
+ if (rem)
return -ETIMEDOUT;
+
/*
* We expect signal_pending(current), but another thread may
* have handled it for us already.
*/
- return -EINTR;
+ if (!abs_time)
+ return -ERESTARTSYS;
+ else {
+ struct restart_block *restart;
+ restart = ¤t_thread_info()->restart_block;
+ restart->fn = futex_wait_restart;
+ restart->arg0 = (unsigned long)uaddr;
+ restart->arg1 = (unsigned long)val;
+ restart->arg2 = (unsigned long)abs_time;
+ restart->arg3 = 0;
+ if (fshared)
+ restart->arg3 |= ARG3_SHARED;
+ return -ERESTART_RESTARTBLOCK;
+ }
out_unlock_release_sem:
queue_unlock(&q, hb);
out_release_sem:
- up_read(&curr->mm->mmap_sem);
+ futex_unlock_mm(fshared);
return ret;
}
+
+static long futex_wait_restart(struct restart_block *restart)
+{
+ u32 __user *uaddr = (u32 __user *)restart->arg0;
+ u32 val = (u32)restart->arg1;
+ ktime_t *abs_time = (ktime_t *)restart->arg2;
+ struct rw_semaphore *fshared = NULL;
+
+ restart->fn = do_no_restart_syscall;
+ if (restart->arg3 & ARG3_SHARED)
+ fshared = ¤t->mm->mmap_sem;
+ return (long)futex_wait(uaddr, fshared, val, abs_time);
+}
+
+
/*
* Userspace tried a 0 -> TID atomic transition of the futex value
* and failed. The kernel side here does the whole locking operation:
* if there are waiters then it will block, it does PI, etc. (Due to
* races the kernel might see a 0 value of the futex too.)
*/
-static int futex_lock_pi(u32 __user *uaddr, int detect, unsigned long sec,
- long nsec, int trylock)
+static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
+ int detect, ktime_t *time, int trylock)
{
struct hrtimer_sleeper timeout, *to = NULL;
struct task_struct *curr = current;
struct futex_hash_bucket *hb;
u32 uval, newval, curval;
struct futex_q q;
- int ret, attempt = 0;
+ int ret, lock_taken, ownerdied = 0, attempt = 0;
if (refill_pi_state_cache())
return -ENOMEM;
- if (sec != MAX_SCHEDULE_TIMEOUT) {
+ if (time) {
to = &timeout;
- hrtimer_init(&to->timer, CLOCK_REALTIME, HRTIMER_ABS);
+ hrtimer_init(&to->timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
hrtimer_init_sleeper(to, current);
- to->timer.expires = ktime_set(sec, nsec);
+ to->timer.expires = *time;
}
q.pi_state = NULL;
retry:
- down_read(&curr->mm->mmap_sem);
+ futex_lock_mm(fshared);
- ret = get_futex_key(uaddr, &q.key);
+ ret = get_futex_key(uaddr, fshared, &q.key);
if (unlikely(ret != 0))
goto out_release_sem;
+ retry_unlocked:
hb = queue_lock(&q, -1, NULL);
retry_locked:
+ ret = lock_taken = 0;
+
/*
* To avoid races, we attempt to take the lock here again
* (by doing a 0 -> TID atomic cmpxchg), while holding all
*/
newval = current->pid;
- inc_preempt_count();
- curval = futex_atomic_cmpxchg_inatomic(uaddr, 0, newval);
- dec_preempt_count();
+ curval = cmpxchg_futex_value_locked(uaddr, 0, newval);
if (unlikely(curval == -EFAULT))
goto uaddr_faulted;
- /* We own the lock already */
+ /*
+ * Detect deadlocks. In case of REQUEUE_PI this is a valid
+ * situation and we return success to user space.
+ */
if (unlikely((curval & FUTEX_TID_MASK) == current->pid)) {
- if (!detect && 0)
- force_sig(SIGKILL, current);
ret = -EDEADLK;
goto out_unlock_release_sem;
}
/*
- * Surprise - we got the lock. Just return
- * to userspace:
+ * Surprise - we got the lock. Just return to userspace:
*/
if (unlikely(!curval))
goto out_unlock_release_sem;
uval = curval;
- newval = uval | FUTEX_WAITERS;
- inc_preempt_count();
- curval = futex_atomic_cmpxchg_inatomic(uaddr, uval, newval);
- dec_preempt_count();
+ /*
+ * Set the WAITERS flag, so the owner will know it has someone
+ * to wake at next unlock
+ */
+ newval = curval | FUTEX_WAITERS;
+
+ /*
+ * There are two cases, where a futex might have no owner (the
+ * owner TID is 0): OWNER_DIED. We take over the futex in this
+ * case. We also do an unconditional take over, when the owner
+ * of the futex died.
+ *
+ * This is safe as we are protected by the hash bucket lock !
+ */
+ if (unlikely(ownerdied || !(curval & FUTEX_TID_MASK))) {
+ /* Keep the OWNER_DIED bit */
+ newval = (curval & ~FUTEX_TID_MASK) | current->pid;
+ ownerdied = 0;
+ lock_taken = 1;
+ }
+
+ curval = cmpxchg_futex_value_locked(uaddr, uval, newval);
if (unlikely(curval == -EFAULT))
goto uaddr_faulted;
if (unlikely(curval != uval))
goto retry_locked;
+ /*
+ * We took the lock due to owner died take over.
+ */
+ if (unlikely(lock_taken))
+ goto out_unlock_release_sem;
+
/*
* We dont have the lock. Look up the PI state (or create it if
* we are the first waiter):
*/
- ret = lookup_pi_state(uval, hb, &q);
+ ret = lookup_pi_state(uval, hb, &q.key, &q.pi_state);
if (unlikely(ret)) {
- /*
- * There were no waiters and the owner task lookup
- * failed. When the OWNER_DIED bit is set, then we
- * know that this is a robust futex and we actually
- * take the lock. This is safe as we are protected by
- * the hash bucket lock. We also set the waiters bit
- * unconditionally here, to simplify glibc handling of
- * multiple tasks racing to acquire the lock and
- * cleanup the problems which were left by the dead
- * owner.
- */
- if (curval & FUTEX_OWNER_DIED) {
- uval = newval;
- newval = current->pid |
- FUTEX_OWNER_DIED | FUTEX_WAITERS;
+ switch (ret) {
- inc_preempt_count();
- curval = futex_atomic_cmpxchg_inatomic(uaddr,
- uval, newval);
- dec_preempt_count();
+ case -EAGAIN:
+ /*
+ * Task is exiting and we just wait for the
+ * exit to complete.
+ */
+ queue_unlock(&q, hb);
+ futex_unlock_mm(fshared);
+ cond_resched();
+ goto retry;
- if (unlikely(curval == -EFAULT))
+ case -ESRCH:
+ /*
+ * No owner found for this futex. Check if the
+ * OWNER_DIED bit is set to figure out whether
+ * this is a robust futex or not.
+ */
+ if (get_futex_value_locked(&curval, uaddr))
goto uaddr_faulted;
- if (unlikely(curval != uval))
+
+ /*
+ * We simply start over in case of a robust
+ * futex. The code above will take the futex
+ * and return happy.
+ */
+ if (curval & FUTEX_OWNER_DIED) {
+ ownerdied = 1;
goto retry_locked;
- ret = 0;
+ }
+ default:
+ goto out_unlock_release_sem;
}
- goto out_unlock_release_sem;
}
/*
* Now the futex is queued and we have checked the data, we
* don't want to hold mmap_sem while we sleep.
*/
- up_read(&curr->mm->mmap_sem);
+ futex_unlock_mm(fshared);
WARN_ON(!q.pi_state);
/*
ret = ret ? 0 : -EWOULDBLOCK;
}
- down_read(&curr->mm->mmap_sem);
+ futex_lock_mm(fshared);
spin_lock(q.lock_ptr);
- /*
- * Got the lock. We might not be the anticipated owner if we
- * did a lock-steal - fix up the PI-state in that case.
- */
- if (!ret && q.pi_state->owner != curr) {
- u32 newtid = current->pid | FUTEX_WAITERS;
-
- /* Owner died? */
- if (q.pi_state->owner != NULL) {
- spin_lock_irq(&q.pi_state->owner->pi_lock);
- WARN_ON(list_empty(&q.pi_state->list));
- list_del_init(&q.pi_state->list);
- spin_unlock_irq(&q.pi_state->owner->pi_lock);
- } else
- newtid |= FUTEX_OWNER_DIED;
-
- q.pi_state->owner = current;
-
- spin_lock_irq(¤t->pi_lock);
- WARN_ON(!list_empty(&q.pi_state->list));
- list_add(&q.pi_state->list, ¤t->pi_state_list);
- spin_unlock_irq(¤t->pi_lock);
-
- /* Unqueue and drop the lock */
- unqueue_me_pi(&q, hb);
- up_read(&curr->mm->mmap_sem);
+ if (!ret) {
/*
- * We own it, so we have to replace the pending owner
- * TID. This must be atomic as we have preserve the
- * owner died bit here.
+ * Got the lock. We might not be the anticipated owner
+ * if we did a lock-steal - fix up the PI-state in
+ * that case:
*/
- ret = get_user(uval, uaddr);
- while (!ret) {
- newval = (uval & FUTEX_OWNER_DIED) | newtid;
- curval = futex_atomic_cmpxchg_inatomic(uaddr,
- uval, newval);
- if (curval == -EFAULT)
- ret = -EFAULT;
- if (curval == uval)
- break;
- uval = curval;
- }
+ if (q.pi_state->owner != curr)
+ ret = fixup_pi_state_owner(uaddr, &q, curr);
} else {
/*
* Catch the rare case, where the lock was released
- * when we were on the way back before we locked
- * the hash bucket.
+ * when we were on the way back before we locked the
+ * hash bucket.
*/
- if (ret && q.pi_state->owner == curr) {
- if (rt_mutex_trylock(&q.pi_state->pi_mutex))
- ret = 0;
+ if (q.pi_state->owner == curr &&
+ rt_mutex_trylock(&q.pi_state->pi_mutex)) {
+ ret = 0;
+ } else {
+ /*
+ * Paranoia check. If we did not take the lock
+ * in the trylock above, then we should not be
+ * the owner of the rtmutex, neither the real
+ * nor the pending one:
+ */
+ if (rt_mutex_owner(&q.pi_state->pi_mutex) == curr)
+ printk(KERN_ERR "futex_lock_pi: ret = %d "
+ "pi-mutex: %p pi-state %p\n", ret,
+ q.pi_state->pi_mutex.owner,
+ q.pi_state->owner);
}
- /* Unqueue and drop the lock */
- unqueue_me_pi(&q, hb);
- up_read(&curr->mm->mmap_sem);
}
- if (!detect && ret == -EDEADLK && 0)
- force_sig(SIGKILL, current);
+ /* Unqueue and drop the lock */
+ unqueue_me_pi(&q);
+ futex_unlock_mm(fshared);
return ret != -EINTR ? ret : -ERESTARTNOINTR;
queue_unlock(&q, hb);
out_release_sem:
- up_read(&curr->mm->mmap_sem);
+ futex_unlock_mm(fshared);
return ret;
uaddr_faulted:
* non-atomically. Therefore, if get_user below is not
* enough, we need to handle the fault ourselves, while
* still holding the mmap_sem.
+ *
+ * ... and hb->lock. :-) --ANK
*/
+ queue_unlock(&q, hb);
+
if (attempt++) {
- if (futex_handle_fault((unsigned long)uaddr, attempt)) {
- ret = -EFAULT;
- goto out_unlock_release_sem;
- }
- goto retry_locked;
+ ret = futex_handle_fault((unsigned long)uaddr, fshared,
+ attempt);
+ if (ret)
+ goto out_release_sem;
+ goto retry_unlocked;
}
- queue_unlock(&q, hb);
- up_read(&curr->mm->mmap_sem);
+ futex_unlock_mm(fshared);
ret = get_user(uval, uaddr);
if (!ret && (uval != -EFAULT))
* This is the in-kernel slowpath: we look up the PI state (if any),
* and do the rt-mutex unlock.
*/
-static int futex_unlock_pi(u32 __user *uaddr)
+static int futex_unlock_pi(u32 __user *uaddr, struct rw_semaphore *fshared)
{
struct futex_hash_bucket *hb;
struct futex_q *this, *next;
u32 uval;
- struct list_head *head;
+ struct plist_head *head;
union futex_key key;
int ret, attempt = 0;
/*
* First take all the futex related locks:
*/
- down_read(¤t->mm->mmap_sem);
+ futex_lock_mm(fshared);
- ret = get_futex_key(uaddr, &key);
+ ret = get_futex_key(uaddr, fshared, &key);
if (unlikely(ret != 0))
goto out;
hb = hash_futex(&key);
+retry_unlocked:
spin_lock(&hb->lock);
-retry_locked:
/*
* To avoid races, try to do the TID -> 0 atomic transition
* again. If it succeeds then we can return without waking
* anyone else up:
*/
- if (!(uval & FUTEX_OWNER_DIED)) {
- inc_preempt_count();
- uval = futex_atomic_cmpxchg_inatomic(uaddr, current->pid, 0);
- dec_preempt_count();
- }
+ if (!(uval & FUTEX_OWNER_DIED))
+ uval = cmpxchg_futex_value_locked(uaddr, current->pid, 0);
+
if (unlikely(uval == -EFAULT))
goto pi_faulted;
*/
head = &hb->chain;
- list_for_each_entry_safe(this, next, head, list) {
+ plist_for_each_entry_safe(this, next, head, list) {
if (!match_futex (&this->key, &key))
continue;
ret = wake_futex_pi(uaddr, uval, this);
out_unlock:
spin_unlock(&hb->lock);
out:
- up_read(¤t->mm->mmap_sem);
+ futex_unlock_mm(fshared);
return ret;
* non-atomically. Therefore, if get_user below is not
* enough, we need to handle the fault ourselves, while
* still holding the mmap_sem.
+ *
+ * ... and hb->lock. --ANK
*/
+ spin_unlock(&hb->lock);
+
if (attempt++) {
- if (futex_handle_fault((unsigned long)uaddr, attempt)) {
- ret = -EFAULT;
- goto out_unlock;
- }
- goto retry_locked;
+ ret = futex_handle_fault((unsigned long)uaddr, fshared,
+ attempt);
+ if (ret)
+ goto out;
+ uval = 0;
+ goto retry_unlocked;
}
- spin_unlock(&hb->lock);
- up_read(¤t->mm->mmap_sem);
+ futex_unlock_mm(fshared);
ret = get_user(uval, uaddr);
if (!ret && (uval != -EFAULT))
poll_wait(filp, &q->waiters, wait);
/*
- * list_empty() is safe here without any lock.
+ * plist_node_empty() is safe here without any lock.
* q->lock_ptr != 0 is not safe, because of ordering against wakeup.
*/
- if (list_empty(&q->list))
+ if (plist_node_empty(&q->list))
ret = POLLIN | POLLRDNORM;
return ret;
}
-static struct file_operations futex_fops = {
+static const struct file_operations futex_fops = {
.release = futex_close,
.poll = futex_poll,
};
struct futex_q *q;
struct file *filp;
int ret, err;
+ struct rw_semaphore *fshared;
+ static unsigned long printk_interval;
+
+ if (printk_timed_ratelimit(&printk_interval, 60 * 60 * 1000)) {
+ printk(KERN_WARNING "Process `%s' used FUTEX_FD, which "
+ "will be removed from the kernel in June 2007\n",
+ current->comm);
+ }
ret = -EINVAL;
if (!valid_signal(signal))
goto out;
}
filp->f_op = &futex_fops;
- filp->f_vfsmnt = mntget(futex_mnt);
- filp->f_dentry = dget(futex_mnt->mnt_root);
- filp->f_mapping = filp->f_dentry->d_inode->i_mapping;
+ filp->f_path.mnt = mntget(futex_mnt);
+ filp->f_path.dentry = dget(futex_mnt->mnt_root);
+ filp->f_mapping = filp->f_path.dentry->d_inode->i_mapping;
if (signal) {
err = __f_setown(filp, task_pid(current), PIDTYPE_PID, 1);
}
q->pi_state = NULL;
- down_read(¤t->mm->mmap_sem);
- err = get_futex_key(uaddr, &q->key);
+ fshared = ¤t->mm->mmap_sem;
+ down_read(fshared);
+ err = get_futex_key(uaddr, fshared, &q->key);
if (unlikely(err != 0)) {
- up_read(¤t->mm->mmap_sem);
+ up_read(fshared);
kfree(q);
goto error;
}
filp->private_data = q;
queue_me(q, ret, filp);
- up_read(¤t->mm->mmap_sem);
+ up_read(fshared);
/* Now we map fd to filp, so userspace can access it */
fd_install(ret, filp);
* Wake robust non-PI futexes here. The wakeup of
* PI futexes happens in exit_pi_state():
*/
- if (!pi) {
- if (uval & FUTEX_WAITERS)
- futex_wake(uaddr, 1);
- }
+ if (!pi && (uval & FUTEX_WAITERS))
+ futex_wake(uaddr, &curr->mm->mmap_sem, 1);
}
return 0;
}
void exit_robust_list(struct task_struct *curr)
{
struct robust_list_head __user *head = curr->robust_list;
- struct robust_list __user *entry, *pending;
- unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
+ struct robust_list __user *entry, *next_entry, *pending;
+ unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip;
unsigned long futex_offset;
+ int rc;
/*
* Fetch the list head (which was registered earlier, via
if (fetch_robust_entry(&pending, &head->list_op_pending, &pip))
return;
- if (pending)
- handle_futex_death((void __user *)pending + futex_offset, curr, pip);
-
+ next_entry = NULL; /* avoid warning with gcc */
while (entry != &head->list) {
+ /*
+ * Fetch the next entry in the list before calling
+ * handle_futex_death:
+ */
+ rc = fetch_robust_entry(&next_entry, &entry->next, &next_pi);
/*
* A pending lock might already be on the list, so
* don't process it twice:
if (handle_futex_death((void __user *)entry + futex_offset,
curr, pi))
return;
- /*
- * Fetch the next entry in the list:
- */
- if (fetch_robust_entry(&entry, &entry->next, &pi))
+ if (rc)
return;
+ entry = next_entry;
+ pi = next_pi;
/*
* Avoid excessively long or circular lists:
*/
cond_resched();
}
+
+ if (pending)
+ handle_futex_death((void __user *)pending + futex_offset,
+ curr, pip);
}
-long do_futex(u32 __user *uaddr, int op, u32 val, unsigned long timeout,
+long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
u32 __user *uaddr2, u32 val2, u32 val3)
{
int ret;
+ int cmd = op & FUTEX_CMD_MASK;
+ struct rw_semaphore *fshared = NULL;
- switch (op) {
+ if (!(op & FUTEX_PRIVATE_FLAG))
+ fshared = ¤t->mm->mmap_sem;
+
+ switch (cmd) {
case FUTEX_WAIT:
- ret = futex_wait(uaddr, val, timeout);
+ ret = futex_wait(uaddr, fshared, val, timeout);
break;
case FUTEX_WAKE:
- ret = futex_wake(uaddr, val);
+ ret = futex_wake(uaddr, fshared, val);
break;
case FUTEX_FD:
/* non-zero val means F_SETOWN(getpid()) & F_SETSIG(val) */
ret = futex_fd(uaddr, val);
break;
case FUTEX_REQUEUE:
- ret = futex_requeue(uaddr, uaddr2, val, val2, NULL);
+ ret = futex_requeue(uaddr, fshared, uaddr2, val, val2, NULL);
break;
case FUTEX_CMP_REQUEUE:
- ret = futex_requeue(uaddr, uaddr2, val, val2, &val3);
+ ret = futex_requeue(uaddr, fshared, uaddr2, val, val2, &val3);
break;
case FUTEX_WAKE_OP:
- ret = futex_wake_op(uaddr, uaddr2, val, val2, val3);
+ ret = futex_wake_op(uaddr, fshared, uaddr2, val, val2, val3);
break;
case FUTEX_LOCK_PI:
- ret = futex_lock_pi(uaddr, val, timeout, val2, 0);
+ ret = futex_lock_pi(uaddr, fshared, val, timeout, 0);
break;
case FUTEX_UNLOCK_PI:
- ret = futex_unlock_pi(uaddr);
+ ret = futex_unlock_pi(uaddr, fshared);
break;
case FUTEX_TRYLOCK_PI:
- ret = futex_lock_pi(uaddr, 0, timeout, val2, 1);
+ ret = futex_lock_pi(uaddr, fshared, 0, timeout, 1);
break;
default:
ret = -ENOSYS;
struct timespec __user *utime, u32 __user *uaddr2,
u32 val3)
{
- struct timespec t;
- unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
+ struct timespec ts;
+ ktime_t t, *tp = NULL;
u32 val2 = 0;
+ int cmd = op & FUTEX_CMD_MASK;
- if (utime && (op == FUTEX_WAIT || op == FUTEX_LOCK_PI)) {
- if (copy_from_user(&t, utime, sizeof(t)) != 0)
+ if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI)) {
+ if (copy_from_user(&ts, utime, sizeof(ts)) != 0)
return -EFAULT;
- if (!timespec_valid(&t))
+ if (!timespec_valid(&ts))
return -EINVAL;
- if (op == FUTEX_WAIT)
- timeout = timespec_to_jiffies(&t) + 1;
- else {
- timeout = t.tv_sec;
- val2 = t.tv_nsec;
- }
+
+ t = timespec_to_ktime(ts);
+ if (cmd == FUTEX_WAIT)
+ t = ktime_add(ktime_get(), t);
+ tp = &t;
}
/*
- * requeue parameter in 'utime' if op == FUTEX_REQUEUE.
+ * requeue parameter in 'utime' if cmd == FUTEX_REQUEUE.
+ * number of waiters to wake in 'utime' if cmd == FUTEX_WAKE_OP.
*/
- if (op == FUTEX_REQUEUE || op == FUTEX_CMP_REQUEUE)
+ if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE ||
+ cmd == FUTEX_WAKE_OP)
val2 = (u32) (unsigned long) utime;
- return do_futex(uaddr, op, val, timeout, uaddr2, val2, val3);
+ return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
}
static int futexfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data,
struct vfsmount *mnt)
{
- return get_sb_pseudo(fs_type, "futex", NULL, 0xBAD1DEA, mnt);
+ return get_sb_pseudo(fs_type, "futex", NULL, FUTEXFS_SUPER_MAGIC, mnt);
}
static struct file_system_type futex_fs_type = {
static int __init init(void)
{
- unsigned int i;
+ int i = register_filesystem(&futex_fs_type);
+
+ if (i)
+ return i;
- register_filesystem(&futex_fs_type);
futex_mnt = kern_mount(&futex_fs_type);
+ if (IS_ERR(futex_mnt)) {
+ unregister_filesystem(&futex_fs_type);
+ return PTR_ERR(futex_mnt);
+ }
for (i = 0; i < ARRAY_SIZE(futex_queues); i++) {
- INIT_LIST_HEAD(&futex_queues[i].chain);
+ plist_head_init(&futex_queues[i].chain, &futex_queues[i].lock);
spin_lock_init(&futex_queues[i].lock);
}
return 0;
Code Review / linux-3.10.git / blobdiff