Messages in this thread |  | | Date | Tue, 5 Nov 1996 18:53:05 +0000 (GMT) | From | Peter Denison <> | Subject | Re: Block device interface could use some work |
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On Mon, 4 Nov 1996, Theodre Ts'o wrote:
[ Block device driver abstraction ] > After looking at the code (fortunately, I had not just eaten), I've come > to the conclusion that the block driver code could use some serious > rototilling. Unlike the tty or SCSI abstraction, there are > device-dependent sections of code in blk.h, ll_rw_blk.h, and other > routines spread across the block device abstraction. The abstraction > boundary itself is not particularily clean, as the SCSI devices, the > CD-ROM devices, and the IDE device drivers feel free to violate the > abstraction boundary and directly muck with the request queue directly, > for performance reasons. (What this probably means is that some of the > things they are trying to do should be incorporated into the blk.h > abstraction.) As a final example, the end_request() function is a > statically defined function defined in blk.h, which is replicated for > each device driver. Here, here. I wouldn't regard myself as competent enough to do it, but I certainly could use it being done. In trying to write the driver for Promise IDE cards, I have come across the problem that I need to issue a request for more than 127 sectors to the interface in two halves. I could not work out how to fit that in to the current "scheme of things".
> The bottom line is that the Linux block driver abstraction is screaming > for a re-write. I currently have too many Linux projects on my plate > (including the aforementioned USELINUX tutorial which caused me to > notice this problem in the first place), so I'm settling for writing a > note to linux-kernel pointing out the problem. Perhaps some of the > people who are currently maintaining block devices would be willing to > take a look at this? Linus? What do you think? > > - Ted > I'll help if I can, but I'll need some direction from those "in the know"
-- Peter Denison <peterd@pnd-pc.demon.co.uk> Currently (still) working on a driver for Promise cards under Linux.
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