Re: Block device request merging - repeated requests.

From: Jens Axboe (axboe@suse.de)
Date: Tue Feb 01 2000 - 08:42:25 EST


On Tue, Feb 01 2000, David Woodhouse wrote:
> I see no CURRENT->b_rsector or b_blocknr.
>
> I assume you mean CURRENT->bh->{b_rsector,b_blocknr} ?

Yes, of course.

> Which? What's the difference? They are documented as "Real buffer location on
> disk" and "block number" respectively, which doesn't really help me choose
> between them.

I found that b_rsector is the 512 byte sector number and b_blocknr is
relative to the block size of the device. b_blocknr is set with
getblk() for example, and here you pass the actual location of the
device. ll_rw_block() sets b_rsector to b_blocknr * (b_size >> 9),
so there you have it.

-- 
*  Jens Axboe <axboe@suse.de>
*  Linux CD-ROM Maintainer
*  http://www.kernel.dk

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