Re: [PATCH 1/2] IB/hfi1: Fix a parameter of find_first_bit.

[Christophe JAILLET]

Le 26/08/2016 Ã 15:35, Doug Ledford a Ãcrit :
> On 8/26/2016 12:49 AM, Christophe JAILLET wrote:
> > The 2nd parameter of 'find_first_bit' is the number of bits to search.
> > In this case, we are passing 'sizeof(unsigned long)' which is likely to
> > be 4 or 8.
> If the size can be 4 or 8, then using 64 universally is not correct.
> Why not use sizeof() * 8 (or << 3)?
I agree with you...

BTW, the log message is wrong. 'port_mask' is a u64. (not an unsigned 
long). So the sizeof should always be 8.
(cut and paste error from another patch, sorry)

> > It is likely that the number of bits of 'port_mask' was expected 
> > here. This
> > variable is a 'u64', so use 64 instead.
> >
> > It has been spotted by the following coccinelle script:
> > @@
> > expression ret, x;
> >
> > @@
> > *  ret = \(find_first_bit \| find_first_zero_bit\) (x, sizeof(...));
> >
> > Signed-off-by: Christophe JAILLET 
> > <christophe.jaillet-39ZsbGIQGT5GWvitb5QawA@xxxxxxxxxxxxxxxx>
> > ---
> > Not sure that using 64 directly is the best option.
> > Maybe '8 * sizeof(port_mask)' as used in the same file for
> > 'for_each_set_bit' would be better
> > ---
... as noted here

Would you like a v2 patch or, will you update it by yourself?

Best regards,
CJ

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