Messages in this thread |  | | Date | Tue, 27 Nov 2001 18:34:18 -0700 | From | "Jeff V. Merkey" <> | Subject | Block I/O Enchancements, 2.5.1-pre2 |
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On Tue, Nov 27, 2001 at 05:04:46PM -0800, Linus Torvalds wrote: > > On Wed, 28 Nov 2001, Paul Mackerras wrote: > > > > Is there a description of the new block layer and its interface to > > block device drivers somewhere? That would be helpful, since Ben > > Herrenschmidt and I are going to have to convert several > > powermac-specific drivers. > > Jens has something written up, which he sent to me as an introduction to > the patch. I'll send that out unless he does a cleaned-up version, but I'd > actually prefer for him to do the sending. Jens? > > Linus >
Linus/Jens,
I've just completed my review of submit_bio and the changes to generic_make_request and I have some questions for whomever can answer.
1. The changes made to submit_bh indicate I can now send long chains of variable block size requests to the I/O layer similiar to the capability of Windows 2000 and NetWare I/O subsystems.
2. The elevator layer is merging these requests, and making a single sweep request for contiguous sector runs.
3. In theory, I should be able to support page cache capability for NWFS and possibly NTFS in Linux the way these wierd non-Unix OS's work.
4. This interface may **NOT** support non-block aligned requests across all the drivers. I also need to be able to submit a request chain 512-2048-512-1024-4096 where the first IO requested may by on a non-block aligned boundry. i.e. Device is configured for 1024 byte blocks, I start the request as 512 @ LBA 1 -> 1024 @ LBA 2, etc. The code looks like it will work.
I would love to test this wonderful code and will hopefully this evening, however, all the SCSI drivers appear to be broken, as well as the 3Ware. :-)
Please advise,
Jeff
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