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>

3 files changed, 43 insertions, 1 deletions

diff --git a/drivers/infiniband/core/cache.c b/drivers/infiniband/core/cache.c
index 50364c0b090c..e05ca2cdc73f 100644
--- a/drivers/infiniband/core/cache.c
+++ b/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 = {
diff --git a/include/rdma/ib_cache.h b/include/rdma/ib_cache.h
index 5bf9834f7dca..f179d233ffc3 100644
--- a/include/rdma/ib_cache.h
+++ b/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 */
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 6bbf1b364400..aeb4fcd86a9e 100644
--- a/include/rdma/ib_verbs.h
+++ b/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 {