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>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/pcmcia/cs.c b/drivers/pcmcia/cs.c
index d529e02c2d54..9a49c394f04f 100644
--- 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)