CVE-2024-58091 drm/fbdev-dma: Add shadow buffering for deferred I/O

In the Linux kernel, the following vulnerability has been resolved: drm/fbdev-dma: Add shadow buffering for deferred I/O DMA areas are not necessarily backed by struct page, so we cannot rely on it for deferred I/O. Allocate a shadow buffer for drivers that require deferred I/O and use it as...