Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/ceph/decode.c b/net/ceph/decode.c
new file mode 100644
index 0000000..eea5295
--- /dev/null
+++ b/net/ceph/decode.c
@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/ceph/decode.h>
+
+static int
+ceph_decode_entity_addr_versioned(void **p, void *end,
+				  struct ceph_entity_addr *addr)
+{
+	int ret;
+	u8 struct_v;
+	u32 struct_len, addr_len;
+	void *struct_end;
+
+	ret = ceph_start_decoding(p, end, 1, "entity_addr_t", &struct_v,
+				  &struct_len);
+	if (ret)
+		goto bad;
+
+	ret = -EINVAL;
+	struct_end = *p + struct_len;
+
+	ceph_decode_copy_safe(p, end, &addr->type, sizeof(addr->type), bad);
+
+	ceph_decode_copy_safe(p, end, &addr->nonce, sizeof(addr->nonce), bad);
+
+	ceph_decode_32_safe(p, end, addr_len, bad);
+	if (addr_len > sizeof(addr->in_addr))
+		goto bad;
+
+	memset(&addr->in_addr, 0, sizeof(addr->in_addr));
+	if (addr_len) {
+		ceph_decode_copy_safe(p, end, &addr->in_addr, addr_len, bad);
+
+		addr->in_addr.ss_family =
+			le16_to_cpu((__force __le16)addr->in_addr.ss_family);
+	}
+
+	/* Advance past anything the client doesn't yet understand */
+	*p = struct_end;
+	ret = 0;
+bad:
+	return ret;
+}
+
+static int
+ceph_decode_entity_addr_legacy(void **p, void *end,
+			       struct ceph_entity_addr *addr)
+{
+	int ret = -EINVAL;
+
+	/* Skip rest of type field */
+	ceph_decode_skip_n(p, end, 3, bad);
+
+	/*
+	 * Clients that don't support ADDR2 always send TYPE_NONE, change it
+	 * to TYPE_LEGACY for forward compatibility.
+	 */
+	addr->type = CEPH_ENTITY_ADDR_TYPE_LEGACY;
+	ceph_decode_copy_safe(p, end, &addr->nonce, sizeof(addr->nonce), bad);
+	memset(&addr->in_addr, 0, sizeof(addr->in_addr));
+	ceph_decode_copy_safe(p, end, &addr->in_addr,
+			      sizeof(addr->in_addr), bad);
+	addr->in_addr.ss_family =
+			be16_to_cpu((__force __be16)addr->in_addr.ss_family);
+	ret = 0;
+bad:
+	return ret;
+}
+
+int
+ceph_decode_entity_addr(void **p, void *end, struct ceph_entity_addr *addr)
+{
+	u8 marker;
+
+	ceph_decode_8_safe(p, end, marker, bad);
+	if (marker == 1)
+		return ceph_decode_entity_addr_versioned(p, end, addr);
+	else if (marker == 0)
+		return ceph_decode_entity_addr_legacy(p, end, addr);
+bad:
+	return -EINVAL;
+}
+EXPORT_SYMBOL(ceph_decode_entity_addr);
+