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From: "Björn Töpel" <bjorn.topel@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org
Cc: "Björn Töpel" <bjorn.topel@intel.com>,
	magnus.karlsson@intel.com, bruce.richardson@intel.com,
	bpf@vger.kernel.org
Subject: [PATCH bpf-next v2 2/2] xsk: support BPF_EXIST and BPF_NOEXIST flags in XSKMAP
Date: Wed, 22 May 2019 15:37:42 +0200
Message-ID: <20190522133742.7654-3-bjorn.topel@gmail.com> (raw)
In-Reply-To: <20190522133742.7654-1-bjorn.topel@gmail.com>

From: Björn Töpel <bjorn.topel@intel.com>

The XSKMAP did not honor the BPF_EXIST/BPF_NOEXIST flags when updating
an entry. This patch addressed that.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
---
 kernel/bpf/xskmap.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c
index 318f6a07fa31..7f4f75ff466b 100644
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c
@@ -223,8 +223,6 @@ static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
 		return -EINVAL;
 	if (unlikely(i >= m->map.max_entries))
 		return -E2BIG;
-	if (unlikely(map_flags == BPF_NOEXIST))
-		return -EEXIST;
 
 	sock = sockfd_lookup(fd, &err);
 	if (!sock)
@@ -250,15 +248,29 @@ static int xsk_map_update_elem(struct bpf_map *map, void *key, void *value,
 
 	spin_lock_bh(&m->lock);
 	entry = &m->xsk_map[i];
+	old_xs = *entry;
+	if (old_xs && map_flags == BPF_NOEXIST) {
+		err = -EEXIST;
+		goto out;
+	} else if (!old_xs && map_flags == BPF_EXIST) {
+		err = -ENOENT;
+		goto out;
+	}
 	xsk_map_node_init(node, m, entry);
 	xsk_map_add_node(xs, node);
-	old_xs = xchg(entry, xs);
+	*entry = xs;
 	if (old_xs)
 		xsk_map_del_node(old_xs, entry);
 	spin_unlock_bh(&m->lock);
 
 	sockfd_put(sock);
 	return 0;
+
+out:
+	spin_unlock_bh(&m->lock);
+	sockfd_put(sock);
+	xsk_map_node_free(node);
+	return err;
 }
 
 static int xsk_map_delete_elem(struct bpf_map *map, void *key)
-- 
2.20.1


      parent reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-22 13:37 [PATCH bpf-next v2 0/2] net: xdp: Two XSKMAP improvements Björn Töpel
2019-05-22 13:37 ` [PATCH bpf-next v2 1/2] xsk: remove AF_XDP socket from map when the socket is released Björn Töpel
2019-06-01 22:32   ` Song Liu
2019-06-03  9:25     ` Björn Töpel
2019-06-06  9:33       ` Björn Töpel
2019-05-22 13:37 ` Björn Töpel [this message]

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