RDMA/core: Introduce new GID table query API

Introduce rdma_query_gid_table which enables querying all the GID tables
of a given device and copying the attributes of all valid GID entries to a
provided buffer.

This API provides a faster way to query a GID table using single call and
will be used in libibverbs to improve current approach that requires
multiple calls to open, close and read multiple sysfs files for a single
GID table entry.

Link: https://lore.kernel.org/r/20200923165015.2491894-4-leon@kernel.org
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/core/cache.c b/drivers/infiniband/core/cache.c
index cf49ac0..3a86a10 100644 (file)
--- a/drivers/infiniband/core/cache.c
+++ b/drivers/infiniband/core/cache.c
@@ -1248,6 +1248,67 @@ done:
 EXPORT_SYMBOL(rdma_get_gid_attr);
 
 /**
+ * rdma_query_gid_table - Reads GID table entries of all the ports of a device up to max_entries.
+ * @device: The device to query.
+ * @entries: Entries where GID entries are returned.
+ * @max_entries: Maximum number of entries that can be returned.
+ * Entries array must be allocated to hold max_entries number of entries.
+ * @num_entries: Updated to the number of entries that were successfully read.
+ *
+ * Returns number of entries on success or appropriate error code.
+ */
+ssize_t rdma_query_gid_table(struct ib_device *device,
+                            struct ib_uverbs_gid_entry *entries,
+                            size_t max_entries)
+{
+       const struct ib_gid_attr *gid_attr;
+       ssize_t num_entries = 0, ret;
+       struct ib_gid_table *table;
+       unsigned int port_num, i;
+       struct net_device *ndev;
+       unsigned long flags;
+
+       rdma_for_each_port(device, port_num) {
+               if (!rdma_ib_or_roce(device, port_num))
+                       continue;
+
+               table = rdma_gid_table(device, port_num);
+               read_lock_irqsave(&table->rwlock, flags);
+               for (i = 0; i < table->sz; i++) {
+                       if (!is_gid_entry_valid(table->data_vec[i]))
+                               continue;
+                       if (num_entries >= max_entries) {
+                               ret = -EINVAL;
+                               goto err;
+                       }
+
+                       gid_attr = &table->data_vec[i]->attr;
+
+                       memcpy(&entries->gid, &gid_attr->gid,
+                              sizeof(gid_attr->gid));
+                       entries->gid_index = gid_attr->index;
+                       entries->port_num = gid_attr->port_num;
+                       entries->gid_type = gid_attr->gid_type;
+                       ndev = rcu_dereference_protected(
+                               gid_attr->ndev,
+                               lockdep_is_held(&table->rwlock));
+                       if (ndev)
+                               entries->netdev_ifindex = ndev->ifindex;
+
+                       num_entries++;
+                       entries++;
+               }
+               read_unlock_irqrestore(&table->rwlock, flags);
+       }
+
+       return num_entries;
+err:
+       read_unlock_irqrestore(&table->rwlock, flags);
+       return ret;
+}
+EXPORT_SYMBOL(rdma_query_gid_table);
+
+/**
  * rdma_put_gid_attr - Release reference to the GID attribute
  * @attr:              Pointer to the GID attribute whose reference
  *                     needs to be released.
@@ -1303,7 +1364,7 @@ struct net_device *rdma_read_gid_attr_ndev_rcu(const struct ib_gid_attr *attr)
        struct ib_gid_table_entry *entry =
                        container_of(attr, struct ib_gid_table_entry, attr);
        struct ib_device *device = entry->attr.device;
-       struct net_device *ndev = ERR_PTR(-ENODEV);
+       struct net_device *ndev = ERR_PTR(-EINVAL);
        u8 port_num = entry->attr.port_num;
        struct ib_gid_table *table;
        unsigned long flags;
@@ -1315,8 +1376,7 @@ struct net_device *rdma_read_gid_attr_ndev_rcu(const struct ib_gid_attr *attr)
        valid = is_gid_entry_valid(table->data_vec[attr->index]);
        if (valid) {
                ndev = rcu_dereference(attr->ndev);
-               if (!ndev ||
-                   (ndev && ((READ_ONCE(ndev->flags) & IFF_UP) == 0)))
+               if (!ndev)
                        ndev = ERR_PTR(-ENODEV);
        }
        read_unlock_irqrestore(&table->rwlock, flags);

diff --git a/include/rdma/ib_cache.h b/include/rdma/ib_cache.h
index 66a8f36..bae29f5 100644 (file)
--- a/include/rdma/ib_cache.h
+++ b/include/rdma/ib_cache.h
@@ -110,5 +110,8 @@ const struct ib_gid_attr *rdma_get_gid_attr(struct ib_device *device,
                                            u8 port_num, int index);
 void rdma_put_gid_attr(const struct ib_gid_attr *attr);
 void rdma_hold_gid_attr(const struct ib_gid_attr *attr);
+ssize_t rdma_query_gid_table(struct ib_device *device,
+                            struct ib_uverbs_gid_entry *entries,
+                            size_t max_entries);
 
 #endif /* _IB_CACHE_H */

diff --git a/include/uapi/rdma/ib_user_ioctl_verbs.h b/include/uapi/rdma/ib_user_ioctl_verbs.h
index fb8cdb3..1482008 100644 (file)
--- a/include/uapi/rdma/ib_user_ioctl_verbs.h
+++ b/include/uapi/rdma/ib_user_ioctl_verbs.h
@@ -251,4 +251,12 @@ enum rdma_driver_id {
        RDMA_DRIVER_SIW,
 };
 
+struct ib_uverbs_gid_entry {
+       __aligned_u64 gid[2];
+       __u32 gid_index;
+       __u32 port_num;
+       __u32 gid_type;
+       __u32 netdev_ifindex; /* It is 0 if there is no netdev associated with it */
+};
+
 #endif