[RFC v2 8/9] kmsg: add ioctl for kmsg* devices operating on buffers

From: Marcin Niesluchowski There is no possibility to clear additional kmsg buffers, get size of them or know what size should be passed to read file operation (too small size causes it to retrun -EINVAL). Add following ioctls which solve those issues: * KMSG_CMD_GET_BUF_SIZE *

[RFC v2 8/9] kmsg: add ioctl for kmsg* devices operating on buffers

From: Marcin Niesluchowski There is no possibility to clear additional kmsg buffers, get size of them or know what size should be passed to read file operation (too small size causes it to retrun -EINVAL). Add following ioctls which solve those issues: *