Messages in this thread | | | Subject | Re: [patch] cache flush bug in mm/filemap.c (all kernels >= 2.5.30(at least)) | From | "David S. Miller" <> | Date | 25 May 2003 20:19:32 -0700 |
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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 :-)
-- David S. Miller <davem@redhat.com> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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