Re: [PATCH v19 0/8] MR3103: server: Create and use a desktop shared mapping for GetCursorPos.

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about server/mapping.c:
> - size = (size + page_mask) & ~((mem_size_t)page_mask);
> -
> - if ((unix_fd = create_temp_file( size )) == -1) return -1;
> - if (!(fd = create_anonymous_fd( &mapping_fd_ops, unix_fd, &session_mapping->obj, FILE_SYNCHRONOUS_IO_NONALERT )))
> - {
> -
>    close( unix_fd );
> -
>    return -1;
> - }
> - if ((new_session.shared = mmap( NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, unix_fd, 0 )) == MAP_FAILED)
> - {
> -
>    release_object( fd );
> -
>    return -1;
> - }
> - allow_fd_caching( fd );
> -
> - SHARED_WRITE_BEGIN( new_session.shared, session_shm_t )

No need to write-lock the new session as nothing can be using the new session yet.

Not using `SHARED_WRITE_BEGIN` for any potentially long-running code makes the shared memory users easier to reason about.