Re: [PATCH 4/4] staging: lustre: obdclass: change object lookup to no wait mode

[Dilger, Andreas]

On May 16, 2018, at 02:00, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> 
> On Tue, May 15, 2018 at 04:02:55PM +0100, James Simmons wrote:
>> 
>>>> 	/*
>>>> 	 * Allocate new object. This may result in rather complicated
>>>> 	 * operations, including fld queries, inode loading, etc.
>>>> 	 */
>>>> 	o = lu_object_alloc(env, dev, f, conf);
>>>> -	if (IS_ERR(o))
>>>> +	if (unlikely(IS_ERR(o)))
>>>> 		return o;
>>>> 
>>> 
>>> This is an unrelated and totally pointless.  likely/unlikely annotations
>>> hurt readability, and they should only be added if it's something which
>>> is going to show up in benchmarking.  lu_object_alloc() is already too
>>> slow for the unlikely() to make a difference and anyway IS_ERR() has an
>>> unlikely built in so it's duplicative...
>> 
>> Sounds like a good checkpatch case to test for :-)
> 
> The likely/unlikely annotations have their place in fast paths so a
> checkpatch warning would get annoying...

I think James was suggesting a check for unlikely(IS_ERR()), or possibly
a check for unlikely() on something that is already unlikely() after CPP
expansion.

Cheers, Andreas
--
Andreas Dilger
Lustre Principal Architect
Intel Corporation