From f5c2be9e9bd934973d3e51b933bf7c03f85d2010 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Tue, 9 Jun 2015 17:42:58 -0500 Subject: [PATCH] greybus: connection: check for duplicate cport ids Check at connection creation time for an attempt to create a connection with an interface CPort ID that's the same as one that's already been created. Define a new helper function to look for such a duplicate. The check for a duplicate is only performed at initialization time, and CPorts are initialized serially for each bundle, so there's no need to acquire the list lock for this search. Signed-off-by: Alex Elder Signed-off-by: Greg Kroah-Hartman --- drivers/staging/greybus/connection.c | 32 ++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-) diff --git a/drivers/staging/greybus/connection.c b/drivers/staging/greybus/connection.c index 8f528c1640e1..ab6c60ec874c 100644 --- a/drivers/staging/greybus/connection.c +++ b/drivers/staging/greybus/connection.c @@ -11,10 +11,22 @@ static DEFINE_SPINLOCK(gb_connections_lock); +/* This is only used at initialization time; no locking is required. */ +static struct gb_connection * +gb_connection_intf_find(struct greybus_host_device *hd, u16 cport_id) +{ + struct gb_connection *connection; + + list_for_each_entry(connection, &hd->connections, hd_links) + if (connection->intf_cport_id == cport_id) + return connection; + return NULL; +} + static struct gb_connection * gb_connection_hd_find(struct greybus_host_device *hd, u16 cport_id) { - struct gb_connection *connection = NULL; + struct gb_connection *connection; unsigned long flags; spin_lock_irqsave(&gb_connections_lock, flags); @@ -22,7 +34,7 @@ gb_connection_hd_find(struct greybus_host_device *hd, u16 cport_id) if (connection->hd_cport_id == cport_id) goto found; connection = NULL; - found: +found: spin_unlock_irqrestore(&gb_connections_lock, flags); return connection; @@ -159,21 +171,29 @@ struct gb_connection *gb_connection_create(struct gb_bundle *bundle, u16 cport_id, u8 protocol_id) { struct gb_connection *connection; - struct greybus_host_device *hd; + struct greybus_host_device *hd = bundle->intf->hd; int retval; u8 major = 0; u8 minor = 1; + /* + * If a manifest tries to reuse a cport, reject it. We + * initialize connections serially so we don't need to worry + * about holding the connection lock. + */ + if (gb_connection_intf_find(hd, cport_id)) { + pr_err("duplicate interface cport id 0x%04hx\n", cport_id); + return NULL; + } + connection = kzalloc(sizeof(*connection), GFP_KERNEL); if (!connection) return NULL; + connection->hd = hd; connection->protocol_id = protocol_id; connection->major = major; connection->minor = minor; - - hd = bundle->intf->hd; - connection->hd = hd; if (!gb_connection_hd_cport_id_alloc(connection)) { gb_protocol_put(connection->protocol); kfree(connection); -- 2.39.2