[PATCH 15/16] pcmcia: avoid sysfs-related lockup for cardbus

[Dominik Brodowski]

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 .

Signed-off-by: Dominik Brodowski <linux at dominikbrodowski.net>
---
 drivers/pcmcia/cs.c |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pcmcia/cs.c b/drivers/pcmcia/cs.c
index ca6975a..8f1a6f6 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)
-- 
1.6.3.3