On Wed, Dec 11, 2013 at 07:55:26AM +0000, Al Viro wrote:
This sucker should return 0. Insufficiently large buffer will be handled by caller, TYVM, if you give that caller a chance to do so. Returning 1 from ->show() is a bug in almost all cases, and definitely so in this one.
Just in case somebody decides that above is worth copying: It Is Not. Original code is buggy, plain and simple. This one trades the older bug ("fail with -EINVAL whenever the buffer is too small") with just as buggy "silently skip an entry entirely whenever the buffer is too small".
Don't Do That.
Pardon - Joe has made seq_overflow return -1 instead of true. Correction to the above, then - s/This trades.*./This is just as buggy./
Conclusion is still the same - Don't Do That. Returning -1 on insufficiently large buffer is a bug, plain and simple.
And this patch series is completely misguided - it doesn't fix any bugs *and* it provides a misleading example for everyone. See the reaction right in this thread, proposing to spread the same bug to currently working iterators.