IB: Add caching of ports' LMC

Add an LMC cache to struct ib_device, and add a function
ib_get_cached_lmc() to query the cache.
Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/cache.c

@@ -191,6 +191,24 @@ int ib_find_cached_pkey(struct ib_device *device,
 }
 EXPORT_SYMBOL(ib_find_cached_pkey);
 
+int ib_get_cached_lmc(struct ib_device *device,
+		      u8                port_num,
+		      u8                *lmc)
+{
+	unsigned long flags;
+	int ret = 0;
+
+	if (port_num < start_port(device) || port_num > end_port(device))
+		return -EINVAL;
+
+	read_lock_irqsave(&device->cache.lock, flags);
+	*lmc = device->cache.lmc_cache[port_num - start_port(device)];
+	read_unlock_irqrestore(&device->cache.lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(ib_get_cached_lmc);
+
 static void ib_cache_update(struct ib_device *device,
 			    u8                port)
 {
@@ -251,6 +269,8 @@ static void ib_cache_update(struct ib_device *device,
 	device->cache.pkey_cache[port - start_port(device)] = pkey_cache;
 	device->cache.gid_cache [port - start_port(device)] = gid_cache;
 
+	device->cache.lmc_cache[port - start_port(device)] = tprops->lmc;
+
 	write_unlock_irq(&device->cache.lock);
 
 	kfree(old_pkey_cache);
@@ -305,7 +325,13 @@ static void ib_cache_setup_one(struct ib_device *device)
 		kmalloc(sizeof *device->cache.gid_cache *
 			(end_port(device) - start_port(device) + 1), GFP_KERNEL);
 
-	if (!device->cache.pkey_cache || !device->cache.gid_cache) {
+	device->cache.lmc_cache = kmalloc(sizeof *device->cache.lmc_cache *
+					  (end_port(device) -
+					   start_port(device) + 1),
+					  GFP_KERNEL);
+
+	if (!device->cache.pkey_cache || !device->cache.gid_cache ||
+	    !device->cache.lmc_cache) {
 		printk(KERN_WARNING "Couldn't allocate cache "
 		       "for %s\n", device->name);
 		goto err;
@@ -333,6 +359,7 @@ err_cache:
 err:
 	kfree(device->cache.pkey_cache);
 	kfree(device->cache.gid_cache);
+	kfree(device->cache.lmc_cache);
 }
 
 static void ib_cache_cleanup_one(struct ib_device *device)
@@ -349,6 +376,7 @@ static void ib_cache_cleanup_one(struct ib_device *device)
 
 	kfree(device->cache.pkey_cache);
 	kfree(device->cache.gid_cache);
+	kfree(device->cache.lmc_cache);
 }
 
 static struct ib_client cache_client = {

include/rdma/ib_cache.h

@@ -102,4 +102,17 @@ int ib_find_cached_pkey(struct ib_device    *device,
 			u16                  pkey,
 			u16                 *index);
 
+/**
+ * ib_get_cached_lmc - Returns a cached lmc table entry
+ * @device: The device to query.
+ * @port_num: The port number of the device to query.
+ * @lmc: The lmc value for the specified port for that device.
+ *
+ * ib_get_cached_lmc() fetches the specified lmc table entry stored in
+ * the local software cache.
+ */
+int ib_get_cached_lmc(struct ib_device *device,
+		      u8                port_num,
+		      u8                *lmc);
+
 #endif /* _IB_CACHE_H */

include/rdma/ib_verbs.h

@@ -827,6 +827,7 @@ struct ib_cache {
 	struct ib_event_handler event_handler;
 	struct ib_pkey_cache  **pkey_cache;
 	struct ib_gid_cache   **gid_cache;
+	u8                     *lmc_cache;
 };
 
 struct ib_device {