On Sat, Nov 26, 2011 at 10:53 PM, Chris Wilson chris@chris-wilson.co.uk wrote:
On Sat, 26 Nov 2011 22:29:12 +0600, Rakib Mullick rakib.mullick@gmail.com wrote:
Yes, no real problem with current code. I was just thinking from code cleanup's pov. Is BUG_ON really needed in i915_add_request() ?
No, just documentation as a reminder that the request should be preallocated, ideally so that we can fail gracefully without touching hardware and leaving it in an inconsistent state wrt to our bookkeeping. (This is more apparent in the overlay code which could hang the chip/driver if we hit a malloc error too late.)
The BUG_ON has certainly outlived its usefulness.
Actually, I'm not seeing how BUG_ON could trigger (though, I've wrongly mentioned in previous thread, if request == NULL, BUG_ON could trigger), it's usefulness will never come into action. Other callers of i915_add_request also makes sure that, it gets called only if (request).
Although, kfree(NULL) is permitted, we shouldn't use it unnecessarily. Anyway, since the issue is not a big deal and no real bug, it could be droped.
Thanks, Rakib