Re: [PATCH 002 of 6] Introduce rq_for_each_segment replacingrq_for_each_bio

From: Satyam Sharma
Date: Sat Aug 18 2007 - 10:36:36 EST




On Sat, 18 Aug 2007, Jan Engelhardt wrote:

> On Aug 18 2007 20:07, Satyam Sharma wrote:
> >On Fri, 17 Aug 2007, Geert Uytterhoeven wrote:
> >
> >> On Thu, 16 Aug 2007, NeilBrown wrote:
> >> [...]
> >> > dev_dbg(&dev->sbd.core,
> >> > "%s:%u: bio %u: %u segs %u sectors from %lu\n",
> >> > - __func__, __LINE__, i, bio_segments(bio),
> >> > - bio_sectors(bio), sector);
> >> > - bio_for_each_segment(bvec, bio, j) {
> >> > + __func__, __LINE__, i, bio_segments(iter.bio),
> >> > + bio_sectors(iter.bio),
> >> > + (unsigned long)iter.bio->bi_sector);
> >> ^^^^^^^^^^^^^^^
> >> Superfluous cast: PS3 is 64-bit only, and casts are evil.
>
> bi_sector is sector_t. The cast is ok, because printf will warn, and rightfully
> so since sector_t may just change its shape underneath. It would not be so much
> of a problem if printf() was not a varargs function, but it is, and hence,
> passing an object bigger than the format specifier can make problems.

Oh yeah, that's why the _cast_ _is_ needed in the first place, by the way.
I was mentioning why the cast itself should be (unsigned long long) otoh.
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