diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-27 12:38:12 -0400 |
---|---|---|
committer | Arnd Bergmann <arnd@arndb.de> | 2010-10-27 22:06:17 +0200 |
commit | f7347ce4ee7c65415f84be915c018473e7076f31 (patch) | |
tree | 613ce14f088ad00bdbc77cdfb686a40a4851180f /fs/locks.c | |
parent | c5b1f0d92c36851aca09ac6c7c0c4f9690ac14f3 (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 'fs/locks.c')
-rw-r--r-- | fs/locks.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/fs/locks.c b/fs/locks.c index 0391d2ff5a4e..85fd9ce1abae 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1505,6 +1505,7 @@ EXPORT_SYMBOL_GPL(vfs_setlease); int fcntl_setlease(unsigned int fd, struct file *filp, long arg) { struct file_lock *fl; + struct fasync_struct *new; struct inode *inode = filp->f_path.dentry->d_inode; int error; @@ -1512,12 +1513,25 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) if (IS_ERR(fl)) return PTR_ERR(fl); + new = fasync_alloc(); + if (!new) { + locks_free_lock(fl); + return -ENOMEM; + } lock_flocks(); error = __vfs_setlease(filp, arg, &fl); if (error || arg == F_UNLCK) goto out_unlock; - error = fasync_helper(fd, filp, 1, &fl->fl_fasync); + /* + * fasync_insert_entry() returns the old entry if any. + * If there was no old entry, then it used 'new' and + * inserted it into the fasync list. Clear new so that + * we don't release it here. + */ + if (!fasync_insert_entry(fd, filp, &fl->fl_fasync, new)) + new = NULL; + if (error < 0) { /* remove lease just inserted by setlease */ fl->fl_type = F_UNLCK | F_INPROGRESS; @@ -1529,6 +1543,8 @@ int fcntl_setlease(unsigned int fd, struct file *filp, long arg) error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0); out_unlock: unlock_flocks(); + if (new) + fasync_free(new); return error; } |