Messages in this thread | | | Date | Tue, 16 Sep 2003 21:55:15 +0200 | From | Jens Axboe <> | Subject | Re: 2.7 block ramblings (was Re: DMA for ide-scsi?) |
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On Tue, Sep 16 2003, Jeff Garzik wrote: > On Mon, Sep 15, 2003 at 09:34:45AM +0200, Jens Axboe wrote: > > On Sat, Sep 13 2003, Jeff Garzik wrote: > > > Oh, and I'm pondering the best way to deliver out-of-bang ATA taskfiles > > > and SCSI cdbs to a device. (for the uninitiated, this is lower level > > > than block devices / cdrom devices / etc.) > > > > > > ... AF_BLOCK is not out of the question ;-) > > > > Eh... I wont comment on that. I think we are way into Garzik lala land > > there :) > > > > I'd prefer just keeping sg_io_hdr, but dumping sg. A fully fledged bsg > > (block sg) implementation. That way programs continue to work like > > before on ATAPI/SCSI, for ATA we can use it as a task file transport. > > I don't propose dumping the ugly "submit cdb/taskfile" ioctls, but we do > need to deprecate them. The ioctls are awful for throughput, async > queueing, and the like. And of course in general, ioctls are evil :) > > And we should deprecate them with a solution that aligns what with Linus > described in Dec 2001 on lkml: a chrdev where userland write(2)s cdbs > and taskfiles, and read(2)s the results. This is where my thinking > picked up: if we are creating a chrdev to send "packets" and receive > responses to those packets............ <insert conclusion here>
== bsg, block sg. Did you read what I wrote? :). I started implementing this and have something that barely works. You just bind a block device to a /dev/sg* char device and use read/write on that. Aka sg.
I don't want ioctls command submission interfaces more than you do.
-- Jens Axboe
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