File ceph-librbd-fix-atomic-shared-pointer.patch of Package ceph

From 7e3f243eae129634359dac1943f85155f6ff3e61 Mon Sep 17 00:00:00 2001
From: Adam Emerson <aemerson@redhat.com>
Date: Mon, 2 Dec 2024 20:21:37 -0500
Subject: [PATCH] librbd: Fix atomic shared pointer situation

The `std::atomic_store<std::shared_ptr>` overload was deprecated in
C++20.

Also, to quote from
https://en.cppreference.com/w/cpp/memory/shared_ptr/atomic

> These functions are typically implemented using mutexes, stored in a
> global hash table where the pointer value is used as the key.

This is terrible.

Sadly, GCC11, which we still have to use for all our test builds,
doesn't support the `std::atomic<std::shared_ptr>` overload, so we
keep the regular `std::shared_ptr` around for it in an `#ifdef`.

Since `atomic_store` can accept any `std::atomic<T>*` as its first
argument, we don't have to change the accesses.

Signed-off-by: Adam Emerson <aemerson@redhat.com>
---
 src/librbd/ImageCtx.h | 4 ++++
 1 file changed, 4 insertions(+)

--- a/src/librbd/ImageCtx.h
+++ b/src/librbd/ImageCtx.h
@@ -363,7 +363,11 @@ namespace librbd {
                                    ceph::mutex **timer_lock);
 
   private:
+#if defined(__cpp_lib_atomic_shared_ptr)
+    std::atomic<std::shared_ptr<neorados::IOContext>> data_io_context;
+#else
     std::shared_ptr<neorados::IOContext> data_io_context;
+#endif //
   };
 }