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authorLinus Torvalds <torvalds@linux-foundation.org>2010-10-27 12:38:12 -0400
committerArnd Bergmann <arnd@arndb.de>2010-10-27 22:06:17 +0200
commitf7347ce4ee7c65415f84be915c018473e7076f31 (patch)
tree613ce14f088ad00bdbc77cdfb686a40a4851180f /include/linux/fs.h
parentc5b1f0d92c36851aca09ac6c7c0c4f9690ac14f3 (diff)
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 <torvalds@linux-foundation.org> [bfields@redhat.com: rebase on top of my changes to Arnd's patch] Tested-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'include/linux/fs.h')
-rw-r--r--include/linux/fs.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8d7de08ab54..56285e5e1de 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);