Messages in this thread | | | Date | Wed, 09 Sep 2015 06:30:42 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH 1/3] sysfs: Fix is_visible() support for binary attributes |
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On 09/09/2015 06:14 AM, Emilio López wrote: > On 09/09/15 01:12, Guenter Roeck wrote: >> On 09/08/2015 08:58 PM, Greg KH wrote: >>> On Tue, Sep 08, 2015 at 06:10:16PM -0700, Guenter Roeck wrote: >>>> Hi Emilio, >>>> >>>> On 09/08/2015 05:51 PM, Emilio López wrote: >>>>> Hi Greg & Guenter, >>>>> >>>> [ ... ] >>>>>>>> >>>>>>>> Unless I am missing something, this is not explained anywhere, >>>>>>>> but it is >>>>>>>> not entirely trivial to understand. I think it should be documented. >>>>> >>>>> I agree. I couldn't find any mention of what this int was supposed >>>>> to be by looking at Documentation/ (is_visible is not even mentioned >>>>> :/) or include/linux/sysfs.h. Once we settle on something I'll >>>>> document it before sending a v2. >>>>> >>>> In the include file ? No strong preference, though. >>>> >>>>> By the way, I wrote a quick coccinelle script to match is_visible() >>>>> users which reference the index (included below), and it found >>>>> references to drivers which do not seem to use any binary >>>>> attributes, so I believe changing the index meaning shouldn't be an >>>>> issue. >>>>> >>>> Good. >>>> >>>>>>> I agree, make i the number of the bin attribute and that should solve >>>>>>> this issue. >>>>>>> >>>>>> No, that would conflict with the "normal" use of is_visible for >>>>>> non-binary >>>>>> attributes, and make the index all but useless, since the >>>>>> is_visible function >>>>>> would have to search through all the attributes anyway to figure >>>>>> out which one >>>>>> is being checked. >>>>> >>>>> Yeah, using the same indexes would be somewhat pointless, although >>>>> not many seem to be using it anyway (only 14 files matched). Others >>>>> seem to be comparing the attr* instead. An alternative would be to >>>>> use negative indexes for binary attributes and positive indexes for >>>>> normal attributes. >>>>> >>>> ... and I probably wrote or reviewed a significant percentage of >>>> those ;-). >>>> >>>> Using negative numbers for binary attributes is an interesting idea. >>>> Kind of unusual, though. Greg, any thoughts on that ? >>> >>> Ick, no, that's a mess, maybe we just could drop the index alltogether? >>> >> >> No, please don't. Having to manually compare dozens of index pointers >> would be >> even more of a mess. > > So, what about keeping it the way it is in the patch, and documenting it thoroughly? Otherwise, we could introduce another "is_bin_visible" function to do this same thing but just on binary attributes, but I'd rather not add a new function pointer if possible. >
I would prefer to keep and document it.
Guenter
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