From f7347ce4ee7c65415f84be915c018473e7076f31 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 27 Oct 2010 12:38:12 -0400 Subject: fasync: re-organize fasync entry insertion to allow it under a spinlock You currently cannot use "fasync_helper()" in an atomic environment to insert a new fasync entry, because it will need to allocate the new "struct fasync_struct". Yet fcntl_setlease() wants to call this under lock_flocks(), which is in the process of being converted from the BKL to a spinlock. In order to fix this, this abstracts out the actual fasync list insertion and the fasync allocations into functions of their own, and teaches fs/locks.c to pre-allocate the fasync_struct entry. That way the actual list insertion can happen while holding the required spinlock. Signed-off-by: Linus Torvalds [bfields@redhat.com: rebase on top of my changes to Arnd's patch] Tested-by: J. Bruce Fields Signed-off-by: Arnd Bergmann --- include/linux/fs.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/fs.h') diff --git a/include/linux/fs.h b/include/linux/fs.h index 8d7de08ab546..56285e5e1de4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1302,6 +1302,11 @@ struct fasync_struct { /* SMP safe fasync helpers: */ extern int fasync_helper(int, struct file *, int, struct fasync_struct **); +extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *); +extern int fasync_remove_entry(struct file *, struct fasync_struct **); +extern struct fasync_struct *fasync_alloc(void); +extern void fasync_free(struct fasync_struct *); + /* can be called from interrupts */ extern void kill_fasync(struct fasync_struct **, int, int); -- cgit v1.2.3