7 files changed, 35 insertions, 9 deletions
diff --git a/src/kernel/coinstats.cpp b/src/kernel/coinstats.cpp
index 06a4b8c974..82d7d8c46b 100644
--- a/src/kernel/coinstats.cpp
+++ b/src/kernel/coinstats.cpp
@@ -48,8 +48,9 @@ uint64_t GetBogoSize(const CScript& script_pub_key)
            script_pub_key.size() /* scriptPubKey */;
 }
 
-CDataStream TxOutSer(const COutPoint& outpoint, const Coin& coin) {
-    CDataStream ss(SER_DISK, PROTOCOL_VERSION);
+DataStream TxOutSer(const COutPoint& outpoint, const Coin& coin)
+{
+    DataStream ss{};
     ss << outpoint;
     ss << static_cast<uint32_t>(coin.nHeight * 2 + coin.fCoinBase);
     ss << coin.out;
diff --git a/src/kernel/coinstats.h b/src/kernel/coinstats.h
index b7c1328e93..54d0e4f664 100644
--- a/src/kernel/coinstats.h
+++ b/src/kernel/coinstats.h
@@ -72,7 +72,7 @@ struct CCoinsStats {
 
 uint64_t GetBogoSize(const CScript& script_pub_key);
 
-CDataStream TxOutSer(const COutPoint& outpoint, const Coin& coin);
+DataStream TxOutSer(const COutPoint& outpoint, const Coin& coin);
 
 std::optional<CCoinsStats> ComputeUTXOStats(CoinStatsHashType hash_type, CCoinsView* view, node::BlockManager& blockman, const std::function<void()>& interruption_point = {});
 } // namespace kernel
diff --git a/src/kernel/context.cpp b/src/kernel/context.cpp
index 15413c1840..1205da869e 100644
--- a/src/kernel/context.cpp
+++ b/src/kernel/context.cpp
@@ -21,12 +21,10 @@ Context::Context()
     LogPrintf("Using the '%s' SHA256 implementation\n", sha256_algo);
     RandomInit();
     ECC_Start();
-    ecc_verify_handle.reset(new ECCVerifyHandle());
 }
 
 Context::~Context()
 {
-    ecc_verify_handle.reset();
     ECC_Stop();
 }
 
diff --git a/src/kernel/context.h b/src/kernel/context.h
index 9746ef994b..f11b7b54f0 100644
--- a/src/kernel/context.h
+++ b/src/kernel/context.h
@@ -7,8 +7,6 @@
 
 #include <memory>
 
-class ECCVerifyHandle;
-
 namespace kernel {
 //! Context struct holding the kernel library's logically global state, and
 //! passed to external libbitcoin_kernel functions which need access to this
@@ -18,8 +16,6 @@ namespace kernel {
 //! State stored directly in this struct should be simple. More complex state
 //! should be stored to std::unique_ptr members pointing to opaque types.
 struct Context {
-    std::unique_ptr<ECCVerifyHandle> ecc_verify_handle;
-
     //! Declare default constructor and destructor that are not inline, so code
     //! instantiating the kernel::Context struct doesn't need to #include class
     //! definitions for all the unique_ptr members.
diff --git a/src/kernel/cs_main.cpp b/src/kernel/cs_main.cpp
new file mode 100644
index 0000000000..c3a08c9695
--- /dev/null
+++ b/src/kernel/cs_main.cpp
@@ -0,0 +1,7 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <sync.h>
+
+RecursiveMutex cs_main;
diff --git a/src/kernel/cs_main.h b/src/kernel/cs_main.h
new file mode 100644
index 0000000000..8d03903b8e
--- /dev/null
+++ b/src/kernel/cs_main.h
@@ -0,0 +1,22 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_KERNEL_CS_MAIN_H
+#define BITCOIN_KERNEL_CS_MAIN_H
+
+#include <sync.h>
+
+/**
+ * Mutex to guard access to validation specific variables, such as reading
+ * or changing the chainstate.
+ *
+ * This may also need to be locked when updating the transaction pool, e.g. on
+ * AcceptToMemoryPool. See CTxMemPool::cs comment for details.
+ *
+ * The transaction pool has a separate lock to allow reading from it and the
+ * chainstate at the same time.
+ */
+extern RecursiveMutex cs_main;
+
+#endif // BITCOIN_KERNEL_CS_MAIN_H
diff --git a/src/kernel/mempool_options.h b/src/kernel/mempool_options.h
index dad6f14c39..beb5fca5e9 100644
--- a/src/kernel/mempool_options.h
+++ b/src/kernel/mempool_options.h
@@ -18,6 +18,8 @@ class CBlockPolicyEstimator;
 
 /** Default for -maxmempool, maximum megabytes of mempool memory usage */
 static constexpr unsigned int DEFAULT_MAX_MEMPOOL_SIZE_MB{300};
+/** Default for -maxmempool when blocksonly is set */
+static constexpr unsigned int DEFAULT_BLOCKSONLY_MAX_MEMPOOL_SIZE_MB{5};
 /** Default for -mempoolexpiry, expiration time for mempool transactions in hours */
 static constexpr unsigned int DEFAULT_MEMPOOL_EXPIRY_HOURS{336};
 /** Default for -mempoolfullrbf, if the transaction replaceability signaling is ignored */