Hi, having had a look at current mainline sources, frankly I've (well, initially...) got trouble understanding what this patch is doing.
It's replacing an aggressive error-type bail-out (-EINVAL) for NULL request_fn with an inoccuous-looking "return ret;", yet that ret content currently *implicitly* is a >= 0 value (resulting from processing by earlier code which may or may not get incomprehensibly rewritten in future). I don't understand the reasons for this huge change in return value handling (since it's now not assigning a specific return value for this modified bail-out case). OK, well... you could say that since all this function ever was interested in is the result value of queue_var_store() (except for error bail-out cases), doing an interim "return ret;" (which is exactly what the function tail is also doing) is exactly right. But still simple textual appearance of the resulting patch hunks seems strangely asymmetric which may easily be a canary for structurally wrong layering of this function. Not to mention the now required extra spin_unlock_irq() in interim return handler... Well, after further analysis I would come to the conclusion that in general queue_requests_store() does a LOT more than it should - since blk-sysfs.c's only (expected!) purpose is to do parameterization of request_queue behaviour as gathered from sysfs attribute space, all that function should ever be concerned with is parsing that sysfs value and then calling a blk helper for configuration of that very attribute value which would *internally* do all the strange internal queue magic that is currently being updated *open-coded* at this supposedly *sysfs*-specific place. Ugh. Main question here: what would one do if one decided to rip out sysfs and use something entirely different for parameterization? Yeah indeed - thought so... So yeah, I'd definitely say that that function is lacking some cleanup which would possibly then even lead (or: would have led ;) to a much more nicely symmetric textual appearance of the patch hunk of the small but quite likely useful change that you currently intend to have here. Thanks, Andreas Mohr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
