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Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation
From: |
Christoph Hellwig |
Subject: |
Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation |
Date: |
Thu, 29 Oct 2009 05:37:08 +0100 |
User-agent: |
Mutt/1.3.28i |
On Wed, Oct 28, 2009 at 08:25:22PM +0100, Hannes Reinecke wrote:
> I don't think we really need two modes.
> My preferred interface here is to pass down scatter-gather lists down
> with every xfer; this way it'll be the responsibility of the driver to
> create the lists in the first place. If it has hardware scatter-gather
> support it can just pass them down, if not it can as easily create a
> scatter-gather list with just one element as a bounce buffer.
Yes. If this really causes performance problems for esp we can add
bounce buffering in that driver later.
> So something like
> - Get next request
> - Attach iovec/bounc-buffer
> - handle request (command/write/read)
> - complete request (callback)
Btw, from some previuous attempts to sort out this code here are some
thing that I think would be beneficial:
- try to create generic scsi device/request structures that the hba
driver can access, and which contain additional private data for
scsi-disk/generic. Information in the generic one would include
the information about the data transfer, the tag and the command
block.
- try to get rid of the tag indexing stuff by just using a pointer to
the generic scsi request in the hba drivers. That should get rid
of a lot of useless list searching.
- [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Hannes Reinecke, 2009/10/27
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Gerd Hoffmann, 2009/10/27
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Hannes Reinecke, 2009/10/28
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Avi Kivity, 2009/10/28
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Christoph Hellwig, 2009/10/28
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Gerd Hoffmann, 2009/10/28
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Gerd Hoffmann, 2009/10/28
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Hannes Reinecke, 2009/10/28
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation,
Christoph Hellwig <=
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Gerd Hoffmann, 2009/10/29
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Gerd Hoffmann, 2009/10/29
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Christoph Hellwig, 2009/10/29
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Anthony Liguori, 2009/10/29
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Christoph Hellwig, 2009/10/29
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Anthony Liguori, 2009/10/29
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Gerd Hoffmann, 2009/10/30
- Re: [Qemu-devel] [PATCH 0/4] megaraid_sas HBA emulation, Hannes Reinecke, 2009/10/30