Hello, On Mon, Aug 13, 2012 at 02:55:11PM -0700, Kent Overstreet wrote: > > If the condition is detectable, WARN_ON_ONCE() please. > > I know I said I liked this idea, but I changed my mind. > > Sticking a WARN_ON_ONCE() there is saying that passing __GFP_WAIT from > under generic_make_request() is always wrong - it might as well be a > BUG_ON() except warn is better for the user. WARN_ON_ONCE(), as opposed to BUG_ON(), doesn't mean that something isn't always wrong. It's just better to always use WARN variant if the system doesn't *need* to be put down immediately to avoid, say, massive data corruption - limping machine is simply better than dead one. > If that's true, then an assertion is completely wrong because we can > just do the right thing instead - mask out __GFP_WAIT if > current->bio_list != NULL and document that it can fail in that > situation. That's worse because it confuses the reader. Taking something which is as well-known as __GFP_WAIT and then silently ignoring it isn't a good idea. Please just add a WARN_ON. Thanks. -- tejun -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
