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authorIngo Molnar <mingo@elte.hu>2010-02-25 03:40:22 -0500
committerIngo Molnar <mingo@elte.hu>2010-02-25 03:40:26 -0500
commit996de8c6fe95c5a9fc524241cc8f142ef0605d3d (patch)
tree0f637ab0d80d6d7e213707ac2d8c1cc16b69523c /fs/fcntl.c
parent017c426138122c8e9b9f5057fbd0567c37b35247 (diff)
parent60b341b778cc2929df16c0a504c91621b3c6a4ad (diff)
Merge commit 'v2.6.33' into core/rcu
Merge reason: Update from -rc4 to -final. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'fs/fcntl.c')
-rw-r--r--fs/fcntl.c102
1 files changed, 66 insertions, 36 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 2cf93ec40a67..97e01dc0d95f 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -618,60 +618,90 @@ static DEFINE_RWLOCK(fasync_lock);
618static struct kmem_cache *fasync_cache __read_mostly; 618static struct kmem_cache *fasync_cache __read_mostly;
619 619
620/* 620/*
621 * fasync_helper() is used by almost all character device drivers 621 * Remove a fasync entry. If successfully removed, return
622 * to set up the fasync queue. It returns negative on error, 0 if it did 622 * positive and clear the FASYNC flag. If no entry exists,
623 * no changes and positive if it added/deleted the entry. 623 * do nothing and return 0.
624 *
625 * NOTE! It is very important that the FASYNC flag always
626 * match the state "is the filp on a fasync list".
627 *
628 * We always take the 'filp->f_lock', in since fasync_lock
629 * needs to be irq-safe.
624 */ 630 */
625int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) 631static int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp)
626{ 632{
627 struct fasync_struct *fa, **fp; 633 struct fasync_struct *fa, **fp;
628 struct fasync_struct *new = NULL;
629 int result = 0; 634 int result = 0;
630 635
631 if (on) { 636 spin_lock(&filp->f_lock);
632 new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); 637 write_lock_irq(&fasync_lock);
633 if (!new) 638 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
634 return -ENOMEM; 639 if (fa->fa_file != filp)
640 continue;
641 *fp = fa->fa_next;
642 kmem_cache_free(fasync_cache, fa);
643 filp->f_flags &= ~FASYNC;
644 result = 1;
645 break;
635 } 646 }
647 write_unlock_irq(&fasync_lock);
648 spin_unlock(&filp->f_lock);
649 return result;
650}
651
652/*
653 * Add a fasync entry. Return negative on error, positive if
654 * added, and zero if did nothing but change an existing one.
655 *
656 * NOTE! It is very important that the FASYNC flag always
657 * match the state "is the filp on a fasync list".
658 */
659static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp)
660{
661 struct fasync_struct *new, *fa, **fp;
662 int result = 0;
663
664 new = kmem_cache_alloc(fasync_cache, GFP_KERNEL);
665 if (!new)
666 return -ENOMEM;
636 667
637 /*
638 * We need to take f_lock first since it's not an IRQ-safe
639 * lock.
640 */
641 spin_lock(&filp->f_lock); 668 spin_lock(&filp->f_lock);
642 write_lock_irq(&fasync_lock); 669 write_lock_irq(&fasync_lock);
643 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { 670 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
644 if (fa->fa_file == filp) { 671 if (fa->fa_file != filp)
645 if(on) { 672 continue;
646 fa->fa_fd = fd; 673 fa->fa_fd = fd;
647 kmem_cache_free(fasync_cache, new); 674 kmem_cache_free(fasync_cache, new);
648 } else { 675 goto out;
649 *fp = fa->fa_next;
650 kmem_cache_free(fasync_cache, fa);
651 result = 1;
652 }
653 goto out;
654 }
655 } 676 }
656 677
657 if (on) { 678 new->magic = FASYNC_MAGIC;
658 new->magic = FASYNC_MAGIC; 679 new->fa_file = filp;
659 new->fa_file = filp; 680 new->fa_fd = fd;
660 new->fa_fd = fd; 681 new->fa_next = *fapp;
661 new->fa_next = *fapp; 682 *fapp = new;
662 *fapp = new; 683 result = 1;
663 result = 1; 684 filp->f_flags |= FASYNC;
664 } 685
665out: 686out:
666 if (on)
667 filp->f_flags |= FASYNC;
668 else
669 filp->f_flags &= ~FASYNC;
670 write_unlock_irq(&fasync_lock); 687 write_unlock_irq(&fasync_lock);
671 spin_unlock(&filp->f_lock); 688 spin_unlock(&filp->f_lock);
672 return result; 689 return result;
673} 690}
674 691
692/*
693 * fasync_helper() is used by almost all character device drivers
694 * to set up the fasync queue, and for regular files by the file
695 * lease code. It returns negative on error, 0 if it did no changes
696 * and positive if it added/deleted the entry.
697 */
698int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
699{
700 if (!on)
701 return fasync_remove_entry(filp, fapp);
702 return fasync_add_entry(fd, filp, fapp);
703}
704
675EXPORT_SYMBOL(fasync_helper); 705EXPORT_SYMBOL(fasync_helper);
676 706
677void __kill_fasync(struct fasync_struct *fa, int sig, int band) 707void __kill_fasync(struct fasync_struct *fa, int sig, int band)