diff options
author | Alan Stern <stern@rowland.harvard.edu> | 2006-09-19 00:28:06 +0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2006-09-26 08:08:40 +0400 |
commit | 7e9f4b2d3e21e87c26025810413ef1592834e63b (patch) | |
tree | 8fa28b786420fede1f3b656ee21289cc4927c6b2 /lib | |
parent | 81107bf531d2524afbcd61f3b4ad57a71295d591 (diff) | |
download | linux-7e9f4b2d3e21e87c26025810413ef1592834e63b.tar.xz |
Driver core: Don't call put methods while holding a spinlock
The klist utility routines currently call _put methods while holding a
spinlock. This is of course illegal; a put routine could try to
unregister a device and hence need to sleep.
No problems have arisen until now because in many cases klist removals
were done synchronously, so the _put methods were never actually used.
In other cases we may simply have been lucky.
This patch (as784) reworks the klist routines so that _put methods are
called only _after_ the klist's spinlock has been released.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/klist.c | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/lib/klist.c b/lib/klist.c index 9c94f0b163a1..120bd175aa78 100644 --- a/lib/klist.c +++ b/lib/klist.c @@ -123,12 +123,10 @@ EXPORT_SYMBOL_GPL(klist_add_tail); static void klist_release(struct kref * kref) { struct klist_node * n = container_of(kref, struct klist_node, n_ref); - void (*put)(struct klist_node *) = n->n_klist->put; + list_del(&n->n_node); complete(&n->n_removed); n->n_klist = NULL; - if (put) - put(n); } static int klist_dec_and_del(struct klist_node * n) @@ -145,10 +143,14 @@ static int klist_dec_and_del(struct klist_node * n) void klist_del(struct klist_node * n) { struct klist * k = n->n_klist; + void (*put)(struct klist_node *) = k->put; spin_lock(&k->k_lock); - klist_dec_and_del(n); + if (!klist_dec_and_del(n)) + put = NULL; spin_unlock(&k->k_lock); + if (put) + put(n); } EXPORT_SYMBOL_GPL(klist_del); @@ -161,10 +163,7 @@ EXPORT_SYMBOL_GPL(klist_del); void klist_remove(struct klist_node * n) { - struct klist * k = n->n_klist; - spin_lock(&k->k_lock); - klist_dec_and_del(n); - spin_unlock(&k->k_lock); + klist_del(n); wait_for_completion(&n->n_removed); } @@ -260,12 +259,15 @@ static struct klist_node * to_klist_node(struct list_head * n) struct klist_node * klist_next(struct klist_iter * i) { struct list_head * next; + struct klist_node * lnode = i->i_cur; struct klist_node * knode = NULL; + void (*put)(struct klist_node *) = i->i_klist->put; spin_lock(&i->i_klist->k_lock); - if (i->i_cur) { - next = i->i_cur->n_node.next; - klist_dec_and_del(i->i_cur); + if (lnode) { + next = lnode->n_node.next; + if (!klist_dec_and_del(lnode)) + put = NULL; } else next = i->i_head->next; @@ -275,6 +277,8 @@ struct klist_node * klist_next(struct klist_iter * i) } i->i_cur = knode; spin_unlock(&i->i_klist->k_lock); + if (put && lnode) + put(lnode); return knode; } |