Messages in this thread | | | Date | Wed, 16 Mar 2011 15:33:21 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 1/4] scatterlist: new helper functions |
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On Tue, 15 Mar 2011 21:18:14 -0700 (PDT) Alex Dubov <oakad@yahoo.com> wrote:
> > > > > I don't think so. > > > > Splitting (or merging) a request and playing with sg lists > > inside a > > driver is a bad idea. Such should be done in the block > > layer. > > > > I still don't see why the block layer can't do that for the > > driver. > > > > I believe that the helper functions for such should not be > > added. > > > > > In a particular case of flash-like devices, letting the block layer > split requests into memory sequential blocks too often results in > unnecessary fragmentation of writes/erases. > > If only one sg entry is requested from the block layer, it will be (more > often than not) only 1 or 2 pages in length, even if total size of > prospective write request spans multiple erase blocks. > > So there are really only two options for legacy memorystick driver: > 1. Play with scatterlists explicitly. > 2. Make it an MTD backend, rather then stand-alone block device. > > The second option makes more sense, but it is not necessarily the optimal > approach for implementation of this particular media format. >
Thanks.
Do you believe that any other driver is likely to ue the sg infrastructure which this patch adds? Should those additions be internal to the memstick code, at least for now?
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