From 9b92d87d37e3892b0096cd728b46154aed1e2d86 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Thu, 19 Oct 2017 16:19:35 -0500
Subject: [PATCH] buffer: remove list _mempool member

This broke the C++ ABI by changing the list structure size.  Also, it's
not necessary as we can infer the mempool by looking at the other list
contents.  We don't (currently) have a need to map an empty list to a
particular mempool and have that state stick.

Fixes: http://tracker.ceph.com/issues/21573
Signed-off-by: Sage Weil <sage@redhat.com>
---
 src/common/buffer.cc | 34 +++++++++++++++++++---------------
 src/include/buffer.h |  4 ++--
 2 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/src/common/buffer.cc b/src/common/buffer.cc
index e5091a0921777..06ab0abe60167 100644
--- a/src/common/buffer.cc
+++ b/src/common/buffer.cc
@@ -960,6 +960,13 @@ public:
 
   bool buffer::ptr::at_buffer_tail() const { return _off + _len == _raw->len; }
 
+  int buffer::ptr::get_mempool() const {
+    if (_raw) {
+      return _raw->mempool;
+    }
+    return mempool::mempool_buffer_anon;
+  }
+
   void buffer::ptr::reassign_to_mempool(int pool) {
     if (_raw) {
       _raw->reassign_to_mempool(pool);
@@ -1512,7 +1519,6 @@ public:
   {
     std::swap(_len, other._len);
     std::swap(_memcopy_count, other._memcopy_count);
-    std::swap(_mempool, other._mempool);
     _buffers.swap(other._buffers);
     append_buffer.swap(other.append_buffer);
     //last_p.swap(other.last_p);
@@ -1685,9 +1691,16 @@ public:
     return is_aligned(CEPH_PAGE_SIZE);
   }
 
+  int buffer::list::get_mempool() const
+  {
+    if (_buffers.empty()) {
+      return mempool::mempool_buffer_anon;
+    }
+    return _buffers.back().get_mempool();
+  }
+
   void buffer::list::reassign_to_mempool(int pool)
   {
-    _mempool = pool;
     if (append_buffer.get_raw()) {
       append_buffer.get_raw()->reassign_to_mempool(pool);
     }
@@ -1698,7 +1711,6 @@ public:
 
   void buffer::list::try_assign_to_mempool(int pool)
   {
-    _mempool = pool;
     if (append_buffer.get_raw()) {
       append_buffer.get_raw()->try_assign_to_mempool(pool);
     }
@@ -1797,10 +1809,7 @@ public:
   void buffer::list::reserve(size_t prealloc)
   {
     if (append_buffer.unused_tail_length() < prealloc) {
-      append_buffer = buffer::create(prealloc);
-      if (_mempool >= 0) {
-	append_buffer.get_raw()->reassign_to_mempool(_mempool);
-      }
+      append_buffer = buffer::create_in_mempool(prealloc, get_mempool());
       append_buffer.set_length(0);   // unused, so far.
     }
   }
@@ -1900,11 +1909,9 @@ public:
     unsigned gap = append_buffer.unused_tail_length();
     if (!gap) {
       // make a new append_buffer!
-      append_buffer = raw_combined::create(CEPH_BUFFER_APPEND_SIZE);
+      append_buffer = raw_combined::create(CEPH_BUFFER_APPEND_SIZE, 0,
+					   get_mempool());
       append_buffer.set_length(0);   // unused, so far.
-      if (_mempool >= 0) {
-	append_buffer.get_raw()->reassign_to_mempool(_mempool);
-      }
     }
     append(append_buffer, append_buffer.append(c) - 1, 1);	// add segment to the list
   }
@@ -1930,11 +1937,8 @@ public:
       size_t need = ROUND_UP_TO(len, sizeof(size_t)) + sizeof(raw_combined);
       size_t alen = ROUND_UP_TO(need, CEPH_BUFFER_ALLOC_UNIT) -
 	sizeof(raw_combined);
-      append_buffer = raw_combined::create(alen, 0);
+      append_buffer = raw_combined::create(alen, 0, get_mempool());
       append_buffer.set_length(0);   // unused, so far.
-      if (_mempool >= 0) {
-	append_buffer.get_raw()->reassign_to_mempool(_mempool);
-      }
     }
   }
 
diff --git a/src/include/buffer.h b/src/include/buffer.h
index 08a9212e18117..fa8689cc6b7d3 100644
--- a/src/include/buffer.h
+++ b/src/include/buffer.h
@@ -290,6 +290,7 @@ namespace buffer CEPH_BUFFER_API {
       return have_raw() && (start() > 0 || end() < raw_length());
     }
 
+    int get_mempool() const;
     void reassign_to_mempool(int pool);
     void try_assign_to_mempool(int pool);
 
@@ -353,7 +354,6 @@ namespace buffer CEPH_BUFFER_API {
     unsigned _len;
     unsigned _memcopy_count; //the total of memcopy using rebuild().
     ptr append_buffer;  // where i put small appends.
-    int _mempool = -1;
 
   public:
     class iterator;
@@ -687,7 +687,6 @@ namespace buffer CEPH_BUFFER_API {
       _memcopy_count = other._memcopy_count;
       last_p = begin();
       append_buffer.swap(other.append_buffer);
-      _mempool = other._mempool;
       other.clear();
       return *this;
     }
@@ -696,6 +695,7 @@ namespace buffer CEPH_BUFFER_API {
     const ptr& front() const { return _buffers.front(); }
     const ptr& back() const { return _buffers.back(); }
 
+    int get_mempool() const;
     void reassign_to_mempool(int pool);
     void try_assign_to_mempool(int pool);
 
-- 
2.39.5