IB/core: Add ib_find_exact_cached_pkey()

When P_Key tables potentially contain both full and partial membership
copies for the same P_Key, we need a function to find the index for an
exact (16-bit) P_Key.

This is necessary when the master forwards QP1 MADs sent by guests.
If the guest has sent the MAD with a limited membership P_Key, we need
to to forward the MAD using the same limited membership P_Key.  Since
the master may have both the limited and the full member P_Keys in its
table, we must make sure to retrieve the limited membership P_Key in
this case.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/infiniband/core/cache.c b/drivers/infiniband/core/cache.c
index 4da381b74f54..80f6cf2449fb 100644
--- a/drivers/infiniband/core/cache.c
+++ b/drivers/infiniband/core/cache.c
@@ -199,6 +199,38 @@ int ib_find_cached_pkey(struct ib_device *device,
 }
 EXPORT_SYMBOL(ib_find_cached_pkey);
 
+int ib_find_exact_cached_pkey(struct ib_device *device,
+			      u8                port_num,
+			      u16               pkey,
+			      u16              *index)
+{
+	struct ib_pkey_cache *cache;
+	unsigned long flags;
+	int i;
+	int ret = -ENOENT;
+
+	if (port_num < start_port(device) || port_num > end_port(device))
+		return -EINVAL;
+
+	read_lock_irqsave(&device->cache.lock, flags);
+
+	cache = device->cache.pkey_cache[port_num - start_port(device)];
+
+	*index = -1;
+
+	for (i = 0; i < cache->table_len; ++i)
+		if (cache->table[i] == pkey) {
+			*index = i;
+			ret = 0;
+			break;
+		}
+
+	read_unlock_irqrestore(&device->cache.lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(ib_find_exact_cached_pkey);
+
 int ib_get_cached_lmc(struct ib_device *device,
 		      u8                port_num,
 		      u8                *lmc)