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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 <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Alex Elder 2015-06-09 17:42:58 -05:00 committed by Greg Kroah-Hartman
parent 8267616b3e
commit f5c2be9e9b
1 changed files with 26 additions and 6 deletions
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32
drivers/staging/greybus/connection.c
View File

@ -11,10 +11,22 @@
static DEFINE_SPINLOCK(gb_connections_lock); 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 * static struct gb_connection *
gb_connection_hd_find(struct greybus_host_device *hd, u16 cport_id) gb_connection_hd_find(struct greybus_host_device *hd, u16 cport_id)
{ {
struct gb_connection *connection = NULL; struct gb_connection *connection;
unsigned long flags; unsigned long flags;
spin_lock_irqsave(&gb_connections_lock, 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) if (connection->hd_cport_id == cport_id)
goto found; goto found;
connection = NULL; connection = NULL;
found: found:
spin_unlock_irqrestore(&gb_connections_lock, flags); spin_unlock_irqrestore(&gb_connections_lock, flags);
return connection; return connection;
@ -159,21 +171,29 @@ struct gb_connection *gb_connection_create(struct gb_bundle *bundle,
u16 cport_id, u8 protocol_id) u16 cport_id, u8 protocol_id)
{ {
struct gb_connection *connection; struct gb_connection *connection;
struct greybus_host_device *hd; struct greybus_host_device *hd = bundle->intf->hd;
int retval; int retval;
u8 major = 0; u8 major = 0;
u8 minor = 1; 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); connection = kzalloc(sizeof(*connection), GFP_KERNEL);
if (!connection) if (!connection)
return NULL; return NULL;
connection->hd = hd;
connection->protocol_id = protocol_id; connection->protocol_id = protocol_id;
connection->major = major; connection->major = major;
connection->minor = minor; connection->minor = minor;
hd = bundle->intf->hd;
connection->hd = hd;
if (!gb_connection_hd_cport_id_alloc(connection)) { if (!gb_connection_hd_cport_id_alloc(connection)) {
gb_protocol_put(connection->protocol); gb_protocol_put(connection->protocol);
kfree(connection); kfree(connection);