Hi Daniel, [...] >>>>> When a jump into the new program has been performed, >>>>> +it won't return to the old one anymore. >>>>> + >>>>> +If no eBPF program is found at the given index of the program array, >>>> >>>> I find this language a little unclear. The array does not contain eBPF >>>> programs, but rather file descriptors. So, what does "not found" here >>>> really mean? (I added a FIXME.) >>> >>> Ok, it's a bit more complicated to explain I guess. So from user space >>> side, a lookup on that map type is not allowed. When user space adds a >>> new file descriptor into the prog map, the kernel internally translates >>> that to the actual program holds reference, etc. The tail call helper is >>> mapped into a eBPF instruction, so no real helper call here. That instruction >>> will then have a register setting as if we'd have a function call, so it >>> has the lookup key and uses it directly to find the array slot. From >>> there, it has access to the actual underlying program. "Not found" means >>> conditions mentioned as earlier above. >> >> Okay I've changed that paragraph to now read: >> >> If no eBPF program is found at the given index of the pro‐ >> gram array (because the map slot doesn't contain a valid >> program file descriptor, the specified lookup index/key is >> out of bounds, or the limit of 32 nested calls has been >> exceed) execution continues with the current eBPF program. >> This can be used as a fall-through for default cases. >> >> Okay? > > Works for me, thanks! Thanks for checking. > I'll drop you some more patches on remaining items, at the very latest after > LinuxCon NA & Plumbers. Thanks. The page is already looking a lot better than the version that went out with the last man-pages release. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
