Messages in this thread | | | Date | Mon, 26 May 2003 08:07:10 +0300 | From | Mika Penttilä <> | Subject | Re: [patch] cache flush bug in mm/filemap.c (all kernels >= 2.5.30(at least)) |
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I don't think the flush_dcache_page thing is done almost anywhere in the block/driver level right now. And we shouldn't be doing io reads to pagecache pages with user mappings anyway normally. direct-io is a different thing.
--Mika
David S. Miller wrote:
>On Fri, 2003-05-23 at 11:34, Russell King wrote: > > >>So no, I don't think it is a device driver issue at all. >> >>DaveM? >> >> > >Oh yes, this part is. If you don't ensure this, everything >breaks. > >At the end of an I/O operation, say to a page cache page, that >data ought to be visible equally to a userspace vs. a kernel >space mapping to that page. > >For example, this is why we use language about "cpu visibility" in the >DMA api documentation and not "kernel cpu visibility" :-) And because >PIO transfers are basically pseudo-DMA they need to make the same exact >guarentees. > >If you've been living in a world where you didn't think this is >necessary, I certainly feel bad for you :-) > > >
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