pcmcia: avoid sysfs-related lockup for cardbus

In cb_free(), we remove some sysfs files -- other sysfs files might
grab ops_mutex, so we cannot hold it while removing sysfs files. This
fixes http://lkml.org/lkml/2010/1/17/88 .

Tested-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

diff --git a/drivers/pcmcia/cs.c b/drivers/pcmcia/cs.c
index d529e02..9a49c39 100644 (file)
--- a/drivers/pcmcia/cs.c
+++ b/drivers/pcmcia/cs.c
@@ -400,10 +400,19 @@ static void socket_shutdown(struct pcmcia_socket *s)
        s->lock_count = 0;
        kfree(s->fake_cis);
        s->fake_cis = NULL;
+       s->functions = 0;
+
+       /* From here on we can be sure that only we (that is, the
+        * pccardd thread) accesses this socket, and all (16-bit)
+        * PCMCIA interactions are gone. Therefore, release
+        * ops_mutex so that we don't get a sysfs-related lockdep
+        * warning.
+        */
+       mutex_unlock(&s->ops_mutex);
+
 #ifdef CONFIG_CARDBUS
        cb_free(s);
 #endif
-       s->functions = 0;
 
        /* give socket some time to power down */
        msleep(100);
@@ -415,7 +424,6 @@ static void socket_shutdown(struct pcmcia_socket *s)
        }
 
        s->state &= ~SOCKET_INUSE;
-       mutex_unlock(&s->ops_mutex);
 }
 
 static int socket_setup(struct pcmcia_socket *skt, int initial_delay)