Messages in this thread | | | Subject | Re: USB mass storage and ARM cache coherency | From | Benjamin Herrenschmidt <> | Date | Thu, 25 Feb 2010 08:13:56 +1100 |
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On Wed, 2010-02-24 at 11:19 -0500, Alan Stern wrote: > > It is but I'm not confident the responsibility for doing that > cleanup > > is at the HCD level. That would impact a lot of HCD activities that > > don't need such flushing since the use of the page is purely > in-kernel. > > That's right. The HCD merely puts data wherever it's told to. It > doesn't know whether the destination is in the page cache, in > userspace, or anywhere else. The same is true for usb-storage.
I'm surprised that usb-storage has an issue here. It shouldn't afaik, since it's just a SCSI driver (or not anymore ?) and the BIO or filesystems handle things there no ? I haven't seen a single call to flush_dcache_page() in any of drivers/scsi, drivers/ata or drivers/ide when I looked...
Cheers, Ben.
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