Hi Michael, Thanks a lot for for intense review of the documentation. Much appreciated. I've addressed all but the below issues, following your suggestions. On 01/20/2015 02:58 PM, Michael Kerrisk (man-pages) wrote: >> + and KDBUS_CMD_ENDPOINT_MAKE (see above). >> + >> + Following items are expected for KDBUS_CMD_BUS_MAKE: >> + KDBUS_ITEM_MAKE_NAME >> + Contains a string to identify the bus name. > > So, up to here, I've seen no definition of 'kdbus_item', which leaves me > asking questions like: what subfield is KDBUS_ITEM_MAKE_NAME stored in? > which subfield holds the pointer to the string? > > Somewhere earlier, kdbus_item needs to be exaplained in more detail, > I think. Hmm, you're quoting text from section 5, and section 4 actually describes the concept of items quite well I believe? >> + __s64 priority; >> + With KDBUS_RECV_USE_PRIORITY set in flags, receive the next message in >> + the queue with at least the given priority. If no such message is waiting >> + in the queue, -ENOMSG is returned. > > ### > How do I simply select the highest priority message, without knowing what > its priority is? The wording is indeed unclear here. KDBUS_RECV_USE_PRIORITY causes the messages to be dequeued by their priority. The 'priority' field is simply a filter that request a minimum priority. By setting this field to the highest possible value, you effectively bypass the filter. I've added a better description now. >> + -ENOMEM The kernel memory is exhausted >> + -ENOTTY Illegal ioctl command issued for the file descriptor > > Why ENOTTY here, rather than EINVAL? The latter is, I beleive, the usual > ioctl() error for invalid commands, I believe (If you keep ENOTTY, add an > explanation in this document.) Hmm, no. -ENOTTY is commonly used as return code when calling ioctls that can't be handled by the FDs they're called on. 'man errno(3)' even states: "ENOTTY Inappropriate I/O control operation (POSIX.1)". >> + -EINVAL Unsupported item attached to command >> + >> +For all ioctls that carry a struct as payload: >> + >> + -EFAULT The supplied data pointer was not 64-bit aligned, or was >> + inaccessible from the kernel side. >> + -EINVAL The size inside the supplied struct was smaller than expected >> + -EMSGSIZE The size inside the supplied struct was bigger than expected > > Why two different errors for smaller and larger than expected? (If you keep things this > way, pelase explain the reason in this document.) Providing a struct that is smaller than the minimum doesn't give the ioctl a valid set of information to process the request. Hence, I think -EINVAL is appropriate. However, -EMSGSIZE is something that users might hit when they make message payloads too big, and I think it's good to have a change to distinguish the two cases in error handling. I added something in the document now. Again, thanks a lot for reading the documentation so accurately! Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
