Re: [PATCH] 2.5.14 IDE 56

Martin Dalecki (dalecki@evision-ventures.com)
Wed, 08 May 2002 13:23:28 +0200


Uz.ytkownik Alan Cox napisa?:
>>Make hdX gone and use the scsi device major/minor number stuff instead.
>>And then just making the ATA driver looking like if it where some
>>incapable SCSI would actually reduce tons of code from kudzu and
>>friends without the need for any adjustment there.
>
>
> The SCSI layer is significant overhead even in 2.5. Right now for example
> it appears to be the primary bottleneck for the aacraid drivers. ATA6 is
> also more capable than SCSI in several areas regardless of the notional
> market positioning.
>
> Linus talked about having a /dev/disc/... which once you have 32bit dev_t
> makes complete sense. What you don't do however is throw IDE through the
> SCSI midlayer, you merely make the /dev/disc/ point call into the right
> drivers - be they raid, scsi or ide. That also lets the scsi emulation
> crap get ripped out of the megaraid and aacraid drivers which will up
> performance.
>
> Alan

Alan... you have taken me wrong. What I mean is just the following.
Take away some minors from use by SCSI (or more propably a common repository)
and use the same ioctl numbers where possible. Perhaps implement
some ioctl here and there... not more!

Not the whole: "we are just another SCSI device on the driver level".
That would not make sense indeed. Since in esp. the SCSI mid-layer isn't
taht pritty too...

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