On 26/02/2025 23:51, Peter Xu wrote:
> On Wed, Feb 26, 2025 at 02:30:42PM +0800, Li Zhijian wrote:
>> control_save_page() is for RDMA only, unfold it to make the code more
>> clear.
>> In addition:
>> - Similar to other branches style in ram_save_target_page(), involve RDMA
>> only if the condition 'migrate_rdma()' is true.
>> - Further simplify the code by removing the RAM_SAVE_CONTROL_NOT_SUPP.
>>
>> Signed-off-by: Li Zhijian <lizhij...@fujitsu.com>
>
> [...]
>
>> @@ -56,7 +55,7 @@ static inline
>> int rdma_control_save_page(QEMUFile *f, ram_addr_t block_offset,
>> ram_addr_t offset, size_t size)
>> {
>> - return RAM_SAVE_CONTROL_NOT_SUPP;
>> + g_assert_not_reached();
>> }
>
> Not sure if some compiler will be unhappy on the retval not provided, but
> anyway we'll see..
There is no problem in fedora 40(gcc 14.2.1) and ubuntu2204(gcc 11.4.0) with
--disable-rdma.
I also noticed we have a few existing same usage:
1708 bool ram_write_tracking_compatible(void)
1709 {
1710 g_assert_not_reached();
1711 }
1712
1713 int ram_write_tracking_start(void)
1714 {
1715 g_assert_not_reached();
1716 }
1717
1718 void ram_write_tracking_stop(void)
1719 {
1720 g_assert_not_reached();
1721 }
I also asked the AI/Deepseek-R1, pasted a piece of his answer
```
3. Why No Warning for Missing return? 🚨
Typical case: A non-void function missing a return triggers -Wreturn-type
warnings (enabled by -Wall).
This case: The noreturn annotation ensures no execution path exists beyond
g_assert_not_reached(). Because the compiler recognizes this, no warning is
necessary.
Conclusion
GCC trusts the noreturn annotation of g_assert_not_reached(), recognizing that
the function’s control flow ends there. Thus, no warning is emitted. For code
safety, ensure assertions are active or add fallback code if needed.
```
>
> Reviewed-by: Peter Xu <pet...@redhat.com>
>
>> #endif
>> #endif
>> --
>> 2.44.0
>>
>
