framebuffer_alloc

/** * framebuffer_alloc - creates a new frame buffer info structure * * @size: size of driver private data, can be zero * @dev: pointer to the device for this fb, this can be NULL * * Creates a new frame buffer info structure. Also reserves @size bytes * for driver private data (info->par). info->par (if any) will be * aligned to sizeof(long). * * Returns the new structure, or NULL if an error occured. * */struct fb_info *framebuffer_alloc(size_t size, struct device *dev){#define BYTES_PER_LONG (BITS_PER_LONG/8)#define PADDING (BYTES_PER_LONG - (sizeof(struct fb_info) % BYTES_PER_LONG))int fb_info_size = sizeof(struct fb_info);struct fb_info *info;char *p;if (size)fb_info_size += PADDING;p = kzalloc(fb_info_size + size, GFP_KERNEL);if (!p)return NULL;info = (struct fb_info *) p;if (size)info->par = p + fb_info_size;info->device = dev;#ifdef CONFIG_FB_BACKLIGHTmutex_init(&info->bl_curve_mutex);#endifreturn info;#undef PADDING#undef BYTES_PER_LONG}

其实从函数的注释说明已经可以理解的很清楚了，这个函数的核心的作用是申请一块空间，并转换为struct fb_info 指针返回，在这个申请过程私有数据空间size并非是必须的，需要的话可以有但并非必须。

需要注意的是kzalloc申请过程做了初始化工作并在其后的过程中给指针的成员device做了赋值工作。