Re: [PATCH 09/10] Change table chaining layout

[Jens Axboe <jens.axboe@oracle.com>]

On Tue, Oct 23 2007, Linus Torvalds wrote:
> My biggest complaint right now is that a lot of users of the sg *filling* 
> functions were mindlessly converted, so we have code like
> 
> 	cryptoloop.c:             sg_set_page(&sg_in, in_page);
> 	cryptoloop.c:             sg_in.offset = in_offs;
> 	cryptoloop.c:             sg_in.length = sz;
> 
> which is just really stupid, and we should have a function for that. But 
> worse is code like this:
> 
> 	ub.c:     sg_set_page(sg, virt_to_page(sc->top_sense));
> 	ub.c:     sg->offset = (unsigned long)sc->top_sense & (PAGE_SIZE-1);
> 	ub.c:     sg->length = UB_SENSE_SIZE;
> 
> which again was converted "line by line" and we actually *do* have a 
> function to do the above three lines as
> 
> 	sg_set_buf(sg, sc->top_sense, UB_SENSE_SIZE);
> 
> where that *single* line is just tons shorter but more importantly, more 
> readable, than the mess that is a brute-force conversion.

I modified sg_set_page() to take a length and offset argument, and
converted these silly sg_set_page(.., virt_to_page(foo)) to just use
sg_set_buf() instead:

 30 files changed, 93 insertions(+), 152 deletions(-)

and it's definitely a win. Added to the pending bits...

-- 
Jens Axboe