On Tue, 1 May 2007 20:58:02 -0700 (PDT) Christoph Lameter <[EMAIL PROTECTED]> wrote:
> On Tue, 1 May 2007, Nate Diller wrote: > > > well, leave it to me to reply too quickly, sorry. i think we should > > leave simple_prepare_write() the way it is, since it's a library > > function itself. the other two callsites in your patch are buffers, > > which may themselves be smaller than a page so you would need a > > special function for just those two uses, there's no other way to > > avoid making two calls to flush_dcache_page(). if it's tremendously > > important to you to eliminate open coding of these, maybe make a > > 'static int buffer_prepare_write()' or some such in fs/buffer.c > > All three sites zap two parts of a page. If we had a > zero_user_page2 like this > > zero_user_page2(page, start1, end1, start2, end2, kmap) > > then all 3 sites could use the same funtion. > > libfs.c: > > zero_user_page_segments(page, 0, from, to, PAGE_CACHE_SIZE, KM_USER0); > > buffer.c: > > zero_user_page_segments(page, from, block_start, to, block_end, KM_USER0) > > zero_user_page_segments(page, blockstart, from, to, block_end, KM_USER0) > yup. And perhaps zero_user_page() becomes a caller to zero_user_page_segments() if we're sure that the compiler will dtrt. > > I did not look through the whole kernel but this zapping segments is > likely frequent given the nature of the blocklayer. > > The 3 call sites pretty ugly on their own. I think it would be good > to have one clearly commented version of this somewhere. Call sites > will be much clearer since you do not have the kmap_ obfuscation nor > the calculation of the length of each segment. Sure. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
